This document summarizes the optimization of supercritical fluid extraction (SFE) of triterpenic acids from Eucalyptus globulus bark using experimental design. SFE was carried out at different temperatures, pressures, and ethanol contents. A factorial design of experiments and response surface methodology were used to analyze the influence of variables on extraction yield and quality, and to optimize the process. The best conditions found were 200 bar, 40°C and 5% ethanol, yielding 1.2% extract, 50% triterpenic acid concentration, and 79.2% recovery compared to Soxhlet extraction. Pressure and ethanol content had significant effects on extraction, while temperature had little effect.
An investigation on the potential of extracting natural dyes from beetroot an...eSAT Journals
Abstract
Today, owing to the environmental and health drawbacks associated with synthetics dyes, stringent standards are imposed by many countries including Mauritius. Following this issue, great enthusiasm is evoked in the rival of natural colourants which are nowadays gaining popularity due to their green approach. Two well-known, readily available and low cost natural dyes bearing plants in Mauritius namely beetroot (Beta Vulgaris) and turmeric (Curcuma Longa) were opted in this study. A comparative study between the extraction of betalains and curcuminoids from the two plants were systematically evaluated between conventional magnetic stirring (MS) and novel microwave assisted extraction techniques (MAE). The optimum operating conditions to yield maximum hues from the two plant species were 50 % aqueous ethanol, agitation speed of 160 rpm, microwave power of 320 W, particle sizes of 0.45 mm and a solid to solvent ratio (SSR) of 1/35. Under the optimised conditions, the results demonstrated that the extraction yields for MAE were higher and more efficient than the conventional one. Consequently, for MS extraction of beetroot and turmeric, the maximum yields recovered were 69.55 % and 48.00 %, whilst the yield for MAE extraction rose to 89.64 % and 79.73 % respectively. Using the experimental data, this research also explored Peleg’s and Elovich’s kinetic models of dyes extraction.
Keywords: Beetroot, Turmeric, Magnetic stirring, Microwave, Extraction
Optimization of Biodiesel Production from Jatropha Oil using Response Surface...ZY8
1) The document describes research optimizing the production of biodiesel from Jatropha oil through alkali-catalyzed transesterification.
2) A central composite design was used to optimize reaction conditions including methanol-to-oil ratio, sodium hydroxide concentration, and reaction time.
3) The optimal conditions found were a methanol-to-oil ratio of 6.0, 1.0% sodium hydroxide concentration, and a 90 minute reaction time, producing a 99.87% fatty acid methyl ester content.
Extraction of Natural Dyes from Forest Trees and their Application in Textilesijsrd.com
The environment - friendly natural dyes are recently enjoying resurgence in popularity because of the concern with the carcinogenic, mutagenic and sensitizing characteristics of many synthetic dyes. Showing concern towards the nature and to avoid pollution of our environment two forest plants Bixa orellana and Caesalpinia sappan were selected as natural dye sources. In this study, from the bark of C. sappan, seeds of B. orellana and combination of B. orellana and C. sappan, the dyes were extracted. The phytochemical compounds present in the extracts were analyzed as carotenoids in B. orellana and anthocyanin, phenolic acids, flavonoids in C. sappan using TLC. The extracts were then applied to cotton fabric using various natural and chemical mordants which were then tested for their color fastness against rubbing and washing to know the efficiency of the dye. This study will help in improving the natural dye resources and replace them with synthetic dyes, consequently leading to a safe environment.
GREEN SOLVENTS BASED ON CHOLINE CHLORIDE FOR THE EXTRACTION OF SPRUCE BARK (P...Michal Jablonsky
Spruce bark is a rich source of extractives, such as condensed tannins, suberin, resin acids and terpenes. Deep eutectic solvents (DESs), a new type of green solvents, were used in this study for obtaining a spruce bark extract with valuable properties. Choline chloride-based eutectic solvents with carboxylic acids and glycerol were used as extractants. The extractions were performed for 1 h at 60 °C under continuous stirring. The antioxidant activities were evaluated using an antioxidant system with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The content of the total phenolics in the extracts was determined spectrometrically according to the Folin-Ciocalteu procedure and expressed as gallic acid equivalent (GAE). The results indicated promising possibilities for the development and usage of eutectic solvents for bark pretreatment. All the tested extracts showed phenolic contents that ranged from 41 to 463 mg GAE/100 g extract. No correlation between the total phenolic content and antioxidant activity was observed. This study demonstrated that DESs are environmentally suitable solvents for extracting phenolic compounds from spruce bark.
The document summarizes a study that investigated the effects of Strobilanthes crispus extract on lipid profiles, antioxidant status, and toxicity in hypercholesterolemic rabbits. Specific objectives were to determine the extract's effects on total cholesterol, triglycerides, LDL, HDL, lipid peroxidation, liver enzymes, and atherosclerotic lesions. Rabbits were fed one of four diets for 12 weeks: control, high-cholesterol, high-cholesterol with 0.2% extract, or high-cholesterol with simvastatin. Blood and tissue samples were analyzed for biomarkers.
The document summarizes research on extracting rotenone from Derris elliptica roots. It discusses the plant's background and uses of rotenone. The study aims to optimize extraction parameters like solvent, particle size and ratio to maximize rotenone yield and content. Experiments use a central composite design and response surface methodology to identify significant factors. Rotenone concentration is determined using HPLC while biological activity is assessed via brine shrimp lethality assays. Statistical analysis of the results helps evaluate the effects of different extraction parameters.
Optimization of neem seed oil extraction process using response surface metho...Alexander Decker
The document describes an experiment that used response surface methodology to optimize the extraction of neem seed oil using solvent extraction. Central composite design was used to evaluate the effects of three factors (solvent composition, temperature, and extraction time) on oil yield and quality characteristics. Forty-two experimental runs were conducted. Regression models developed showed solvent composition and extraction time had significant effects on maximizing oil yield. The maximum predicted oil yield of 43.48% was obtained at 80.77% n-hexane, 34.93°C temperature, and 6 hours extraction time. Validation experiments showed oil yields ranging from 32.85% to 37.20%, matching the simulated values.
Optimization of microwave assisted hydrodistillation of lemongrass (cymbopogo...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
An investigation on the potential of extracting natural dyes from beetroot an...eSAT Journals
Abstract
Today, owing to the environmental and health drawbacks associated with synthetics dyes, stringent standards are imposed by many countries including Mauritius. Following this issue, great enthusiasm is evoked in the rival of natural colourants which are nowadays gaining popularity due to their green approach. Two well-known, readily available and low cost natural dyes bearing plants in Mauritius namely beetroot (Beta Vulgaris) and turmeric (Curcuma Longa) were opted in this study. A comparative study between the extraction of betalains and curcuminoids from the two plants were systematically evaluated between conventional magnetic stirring (MS) and novel microwave assisted extraction techniques (MAE). The optimum operating conditions to yield maximum hues from the two plant species were 50 % aqueous ethanol, agitation speed of 160 rpm, microwave power of 320 W, particle sizes of 0.45 mm and a solid to solvent ratio (SSR) of 1/35. Under the optimised conditions, the results demonstrated that the extraction yields for MAE were higher and more efficient than the conventional one. Consequently, for MS extraction of beetroot and turmeric, the maximum yields recovered were 69.55 % and 48.00 %, whilst the yield for MAE extraction rose to 89.64 % and 79.73 % respectively. Using the experimental data, this research also explored Peleg’s and Elovich’s kinetic models of dyes extraction.
Keywords: Beetroot, Turmeric, Magnetic stirring, Microwave, Extraction
Optimization of Biodiesel Production from Jatropha Oil using Response Surface...ZY8
1) The document describes research optimizing the production of biodiesel from Jatropha oil through alkali-catalyzed transesterification.
2) A central composite design was used to optimize reaction conditions including methanol-to-oil ratio, sodium hydroxide concentration, and reaction time.
3) The optimal conditions found were a methanol-to-oil ratio of 6.0, 1.0% sodium hydroxide concentration, and a 90 minute reaction time, producing a 99.87% fatty acid methyl ester content.
Extraction of Natural Dyes from Forest Trees and their Application in Textilesijsrd.com
The environment - friendly natural dyes are recently enjoying resurgence in popularity because of the concern with the carcinogenic, mutagenic and sensitizing characteristics of many synthetic dyes. Showing concern towards the nature and to avoid pollution of our environment two forest plants Bixa orellana and Caesalpinia sappan were selected as natural dye sources. In this study, from the bark of C. sappan, seeds of B. orellana and combination of B. orellana and C. sappan, the dyes were extracted. The phytochemical compounds present in the extracts were analyzed as carotenoids in B. orellana and anthocyanin, phenolic acids, flavonoids in C. sappan using TLC. The extracts were then applied to cotton fabric using various natural and chemical mordants which were then tested for their color fastness against rubbing and washing to know the efficiency of the dye. This study will help in improving the natural dye resources and replace them with synthetic dyes, consequently leading to a safe environment.
GREEN SOLVENTS BASED ON CHOLINE CHLORIDE FOR THE EXTRACTION OF SPRUCE BARK (P...Michal Jablonsky
Spruce bark is a rich source of extractives, such as condensed tannins, suberin, resin acids and terpenes. Deep eutectic solvents (DESs), a new type of green solvents, were used in this study for obtaining a spruce bark extract with valuable properties. Choline chloride-based eutectic solvents with carboxylic acids and glycerol were used as extractants. The extractions were performed for 1 h at 60 °C under continuous stirring. The antioxidant activities were evaluated using an antioxidant system with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The content of the total phenolics in the extracts was determined spectrometrically according to the Folin-Ciocalteu procedure and expressed as gallic acid equivalent (GAE). The results indicated promising possibilities for the development and usage of eutectic solvents for bark pretreatment. All the tested extracts showed phenolic contents that ranged from 41 to 463 mg GAE/100 g extract. No correlation between the total phenolic content and antioxidant activity was observed. This study demonstrated that DESs are environmentally suitable solvents for extracting phenolic compounds from spruce bark.
The document summarizes a study that investigated the effects of Strobilanthes crispus extract on lipid profiles, antioxidant status, and toxicity in hypercholesterolemic rabbits. Specific objectives were to determine the extract's effects on total cholesterol, triglycerides, LDL, HDL, lipid peroxidation, liver enzymes, and atherosclerotic lesions. Rabbits were fed one of four diets for 12 weeks: control, high-cholesterol, high-cholesterol with 0.2% extract, or high-cholesterol with simvastatin. Blood and tissue samples were analyzed for biomarkers.
The document summarizes research on extracting rotenone from Derris elliptica roots. It discusses the plant's background and uses of rotenone. The study aims to optimize extraction parameters like solvent, particle size and ratio to maximize rotenone yield and content. Experiments use a central composite design and response surface methodology to identify significant factors. Rotenone concentration is determined using HPLC while biological activity is assessed via brine shrimp lethality assays. Statistical analysis of the results helps evaluate the effects of different extraction parameters.
Optimization of neem seed oil extraction process using response surface metho...Alexander Decker
The document describes an experiment that used response surface methodology to optimize the extraction of neem seed oil using solvent extraction. Central composite design was used to evaluate the effects of three factors (solvent composition, temperature, and extraction time) on oil yield and quality characteristics. Forty-two experimental runs were conducted. Regression models developed showed solvent composition and extraction time had significant effects on maximizing oil yield. The maximum predicted oil yield of 43.48% was obtained at 80.77% n-hexane, 34.93°C temperature, and 6 hours extraction time. Validation experiments showed oil yields ranging from 32.85% to 37.20%, matching the simulated values.
Optimization of microwave assisted hydrodistillation of lemongrass (cymbopogo...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document summarizes a study that investigated the effects of drum rotation speed and steam pressure on properties of drum-dried pitaya (dragon fruit) peel powder. Pitaya peel is typically discarded but contains antioxidants, fiber and betacyanin pigments. The study dried pitaya peel using a laboratory drum dryer at rotation speeds of 1-3 rpm and steam pressures of 1-3 bar. Higher rotation speed increased yield percentage but also moisture content. Higher steam pressure decreased yield, moisture content and water activity. The best conditions for betacyanin retention and product stability were 1 rpm and 2 bar, yielding powder with 80.21 mg/g betacyanin and 10.66% moisture. Overall
The document discusses research on optimizing the extraction of rotenone from Derris elliptica roots. It aims to determine processing parameters that maximize the yield of rotenoids resin, rotenone content, and biological activity (LC50). Preliminary experiments identified suitable ranges for solvent type, solvent-to-solid ratio, and raw material particle size. A 2k factorial design was used to evaluate these parameters. Results showed ethanol extraction at a lower solvent ratio and smaller particle size maximized yields, while acetone extraction was best at a higher ratio and larger particle size. Verification experiments confirmed the optimized parameters.
Synthesis and Characterization of Polymeric Drug Binder from Tobacco WastePremier Publishers
In Indian agriculture, tobacco has a prominent place. So, it is but natural that tobacco waste or dust is generated at various stages of post-harvest processing of tobacco and also while manufacturing various products. As rational production and processing of tobacco plant must include the entire biomass, both the main product leaves as well as stalks that remain after harvest. Residues (stalks and small leaves) and significant amounts of leaf scrap and waste generated during processing of tobacco, can serve as a very important secondary raw material from after final processing, a great number of products could be obtained in industry considering that these stalks contain a certain amount of cellulose. The waste obtained after nicotine extraction was utilized for cellulose extraction. The extracted cellulose was converted to value-added product such as cellulose acetate. Prepared cellulose acetate is characterized by Fourier transform infrared spectroscopy (FTIR).
A comparative study of biopolymers and alum in the separation and recovery of...Soumyadeep Mukherjee
This study compares the effectiveness of various biopolymers and alum in recovering pulp fibers from paper mill wastewater through flocculation. Guar gum was found to be the most effective biopolymer, recovering 3.86 mg/L of fibers. Alum displayed the highest particle removal rate. Guar gum, alum, xanthan gum, and locust bean gum removed 94.68%, 97.46%, 92.39%, and 92.46% of turbidity, respectively, at a settling velocity of 0.5 cm/min. Response surface methodology was used to optimize conditions like pH, dose, and mixing speed to obtain the lowest sludge volume index for guar gum. The results indicate similar performance
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
This study evaluated the effectiveness of low-cost biosorbents for removing methylene blue dye from aqueous solutions. Coconut fiber, banana fiber, and sawdust were tested individually and in combinations under stirring and stagnant conditions. The results showed that sawdust removed 99% of dye under stirring and 99.5% under stagnation. Continuous addition of biosorbents removed more dye (99%) than batch or fed-batch methods. A mixed biosorbent of sawdust, banana fiber, and coconut fiber removed over 98% of dye from solutions with concentrations up to 0.4 mg/mL. Lengthy coconut fibers removed 99.5% of dye within 48 hours under stagnant conditions.
IRJET - Novel Method of Lignin Separation from Almond Shells Applying Multipl...IRJET Journal
This document presents a novel method for isolating lignin from almond shells using multiple solvent contacts. Almond shells were treated with various solvent combinations in a reflux setup, including ethanol-water and 3% NaOH solution. FTIR analysis showed the isolated lignin samples matched literature lignin spectra. Two-stage contacting with 3% NaOH solution at both stages yielded the highest lignin amount at 28.33%, concluding it is the most effective isolation method. The study demonstrates the potential for utilizing almond shell waste through lignin extraction.
Textile industries produce huge amounts of polluted
effluents, whereby over 80% of textile dyes are constituted of
Benzedrine based dyes or aromatic hazardous substances azo
groups that are normally discharged to surface and ground water
aquifers. Through the scientific awareness to reach an ecofriendly
system, this research part deals on the optimum
extraction condition of the new neem natural dye, where the
optimization parameters have technical and commercial
importance on cost and color yield. This has been carried out
using water and different concentrations of water-acetone and
water ethanol mixtures at different temperatures, pH values and
time intervals. Data observed that the optimum extraction
condition was achieved with 50% (v/v) acetone, 18% (w/v) neem
amount at pH 9 at 70oC for 60 min where 50% (v/v) wateracetone
exhibited 60 % absorbance percentage compared to (31
and 9) % of 40% (v/v) water-ethanol and water respectively. The
absorbance values are influenced by the properties of solvents
such as, the dipole moment, dielectric constant, and refractive
index values. Aqueous extraction gave less amount of pigment
and was time consuming, promoting the degradation of color
compounds while the other co-solvents increased the extract
solubility, giving high extraction capacity. pH 9 increased the
diffusion coefficients of color component and the temperature at
70oC for 60 min enhanced the de-aggregation of its molecules.
Finally, FTIR analysis investigated the presence of mainly yield
quercetin (flavonoid) compounds in neem extract which is known
to have antibacterial and antifungal properties giving chance to
be applied for antimicrobial textile dyeing in the second part of
this study.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Effect of fast CO2 pressure changes on the yield of lovage (Levisticum offici...Egidijus Dauksas
1) The study investigated the effect of fast CO2 pressure changes on the extraction yield of compounds from lovage and celery plants.
2) It was found that applying frequent pressure changes in the extraction vessel increased the rate of extracting CO2-soluble materials from different parts of lovage and celery plants, compared to constant pressure extraction.
3) However, after sufficient CO2 had passed through the system, the total extraction yields were similar regardless of using constant or fluctuating pressures. The composition of extracts was analyzed and key compounds were identified.
Mass Transfer, Kinetic, Equilibrium, and Thermodynamic Study on Removal of Di...Ratnakaram Venkata Nadh
Three distinct agricultural waste materials, viz., casuarina fruit powder (CFP), sorghum stem powder
(SSP), and banana stem powder (BSP) were used as low-cost adsorbents for the removal of toxic lead(II)
from aqueous solutions. Acid treated adsorbents were characterized by scanning electron microscopy (SEM),
energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). The
effects of parameters like adsorbent dose, pH, temperature, initial metal ion concentration, and time of
adsorption on the removal of Pb(II) were analyzed for each adsorbent individually and the efficiency order
was BSP > SSP > CFP. Based on the extent of compatibility to Freundlich/Langmuir/Dubinin–Radushkevich/
Temkin adsorption isotherms and different models (pseudo-first and second order, Boyd, Weber’s, and
Elovich), chemisorption primarily involved in the case of BSP and SSP, whereas simultaneous occurrence of
chemisorption and physisorption was proposed in the case of CFP correlating with the thermodynamic study
results conducted at different temperatures. Based on the observations, it was proposed that three kinetic
stages involve in the adsorption process, viz., diffusion of sorbate to sorbent, intra particle diffusion, and then
establishment of equilibrium. These adsorbents have a promising role towards the removal of Pb(II) from
industrial wastewater to contribute environmental protection
Tea (Camellia sinensis) Waste for the reduction of Malathion and Phorate in ...Agriculture Journal IJOEAR
Abstract— Diminution of Malathion and Phorate from aqueous solutions by tea waste biomass was examined in a batch experimental setup. Waste tea powder, obtained from University canteen, S.V. University, Tirupati, India has been used as an effective material for the reduction of Malathion and Phorate from aqueous solutions. Characterization of the adsorbent was studied using SEM micrograph and Fourier Transform Infrared spectral analysis. From the FTIR spectrum it is observed that the change in peak position at 3390 cm−1 in the spectrum of the Phorate and Malathion loaded tea powder indicates the binding of these pesticides with hydroxyl groups. The working solutions of the pesticides are in the range of 0.1µg – 1.0µg for Malathion and 0.05µg – 0.5µg for phorate. It was observed that percentage adsorption increased with pH of the liquid phase and reached an optimum value of 95 % for Malathion and 94 % for phorate at pH 7.4 ± 0.2 and pH 7.5 ± 0.2, respectively. The dosage of the adsorbent had showed considerable effect on the adsorption of Malathion and Phorate.
Applications of Ultrasound to modify and dried fruitsPoojaHorti
This document discusses applications of ultrasound to modify and improve dried fruits. It begins with definitions of ultrasound and discusses fruits that are suitable for drying. It explains that ultrasound drying can reduce energy consumption and drying times for fruits compared to conventional drying methods. Various ultrasound drying methods are described, including ultrasound-assisted convective drying, osmotic dehydration, vacuum drying, and freeze drying. Case studies demonstrate how ultrasound pretreatments and drying can increase the drying rate of fruits like strawberries, improve the quality of dried fruits, and retain polyphenols in apples. The conclusion is that ultrasound is effective for accelerating fruit drying processes and maintaining fruit quality compared to conventional drying.
An Experimental Investigation on Treatment of Tannery Effluent Using Azadirac...IJEAB
A preliminary investigation was carried out for the feasibile use of Azadirachta indica leafs powder as a natural coagulant to the treatment of tannery effluent. In this paper, Azadirachta indica leafs powder of 1, 2, 3 and 4mg/L dosages were used. Floc formation in coagulation process had been studied in the laboratory scale to determine the optimum dosage of natural coagulant. The above dosages were used in pre-treated tannery effluent with coagulants were considered to evaluate the percentage removal efficiency on the major pollutants of concern in in tannery effluent such as turbidity, TSS, TDS, COD and BOD. From the observed results, dosage of 3 mg/L gives better removal efficiencies with respect to turbidity, TSS, TDS, COD and BOD and appears to be suitable for tannery effluent treatment, when compared with other dosages.
The development of sustainable bioplastics for new applications in packaging ...Agriculture Journal IJOEAR
Abstract— The advantage of biodegradable plastics is their degradation under the influence of biological systems into substances naturally present in the environment, which are then placed in a natural circulation cycle of matter. Moreover, the biodegradable plastics waste not require additional segregation and separation from households, and are collected together with other organic waste and subjected to recycling under aerobic or anaerobic conditions. Use of bioplastics reduces the harmful effects of waste on the environment, but does not eliminate it completely.
The article presents the results of (bio) degradation studies under industrial and laboratory (MicroOxymax) composting conditions as well as at atmospheric conditions of commercial disposable dishes from the Nature Works® PLA. Were also carried out investigation of abiotic degradation under laboratory conditions. It was found, from the macro- and microscopic observations, that the tested cups (bio) degraded in the selected environments, wherein in a greater extent under industrial composting conditions than in MicroOxymax. The GPC results, which show significantly reduce in the molar mass of the tested samples after specified incubation times in all environments, indicates that the hydrolytic degradation process occurs predominantly.
Statistical Modelling of Drying Characteristics of Unripe Plantain (Musa Para...Dr. Amarjeet Singh
This work is designed to carry out the statistical modelling of the drying characteristics of unripe plantain (Musa paradisiaca) slices and to study the effect of drying temperature and slice thickness on drying characteristics. The test samples were dried in a laboratory scale oven dryer at varying temperatures of 700C, 800C and 900C, and different slice thicknesses of 2mm, 3mm and 4mm.The result obtained indicated that drying temperature and slice thickness had significant effect on drying rate and hence moisture profile. The moisture ratio – drying time data obtained were fitted to ten thin layer drying models. The fit quality obtained with each model was evaluated using statistical tests namely; coefficient of determination (R2), root mean square error (RMSE), reduced chi-square (X2), and standard error of estimate (SEE). Although most of the models fitted quite well to the experimental data, Page and Modified Page models showed the highest average R2 and the lowest average RMSE, X2 and SEE values. Page and modified Page models were selected and found suitable to represent the drying characteristics of unripe plantain slices and predict drying times.
This document discusses optimization and kinetic studies on extracting oil from the marine macroalgae Ulva lactuca for biodiesel production. Six pre-treatment methods were tested to disrupt the algal cells and increase oil extraction efficiency. Parameters like moisture content, particle size, temperature, and solvent composition were optimized to obtain a high oil yield of 10.88% from 30g of algal biomass. Kinetic studies using a first order model determined the extraction has an activation energy of 63.031 kJ/mol. The results show U. lactuca is a suitable feedstock for biodiesel production.
OPTIMIZATION OF SOME MINERAL CONTENTS OF DRIED OSMO-PRETREATED GREEN BELL PEP...Oyeniyi Samuel
This document summarizes a study that used Response Surface Methodology to optimize the mineral content of dried osmotically pretreated green bell peppers. Bell peppers were treated with varying concentrations of salt solutions for different durations, then dried. The mineral contents of magnesium, potassium, and manganese were analyzed. Optimization found the maximum magnesium content was 29.18 mg/100g with 25% salt solution for 180 minutes, maximum potassium was 46.13 mg/100g with 5% salt for 60 minutes, and maximum manganese was 10.96 mg/100g with 15% salt for 150 minutes. Pretreated dried peppers had higher mineral contents than untreated dried peppers.
Antioxidant activity of hedera helix l. extracts and the main phytoconstituentspharmaindexing
This document summarizes a study that evaluated the antioxidant activity of extracts from Hedera helix stems and identified phytochemicals in the most active extract. Ethyl acetate, methanol, dichloromethane and n-hexane extracts were tested for antioxidant effects using DPPH radical scavenging assays. The ethyl acetate extract showed the highest antioxidant activity at 84.95% due to compounds like flavonoids, tannins and triterpenes. Phytochemical analysis confirmed the presence of these compounds in the ethyl acetate extract, suggesting they contribute to its antioxidant properties.
This document describes a study comparing the acetylation of cellulose extracted from Eucalyptus Camaldulensis Dehn wood using microwave irradiation versus conventional heating. Cellulose was acetylated using acetic anhydride with pyridine as a catalyst. The reaction was performed using microwave irradiation for 6 hours and conventional heating for 7 hours. The acetylated products were characterized using FT-IR spectroscopy. The results showed that microwave irradiation led to a faster and cleaner reaction compared to conventional heating. Microwave irradiation is proposed as a more efficient method for acetylating cellulose.
Abstract— Biofuel production from microalgae biomass appears as a promising long term alternative. Dunaliella tertiolecta is a microalgae with high tolerance to salinity, temperature, and light, making it relatively easy to grow. The aim of this study was to establish a pilot-scale culture to evaluate the biomass yield and bioethanol production. The cell culture of D. tertiolecta was started in 20 ml tubes and escalated to 20 L containers. The biomass yield was 0.153 g L-1 of dry basis (db) and its characterization showed protein (37% db) as major component followed by carbohydrates (35.6), lipids (13% db) and ash (6.5%). The carbohydrate fraction was composed of starch (27.1% db) and fiber (8.5 %) and its neutral sugar characterization yield glucose (91% molar). The main components of the lipid fraction were linolenic and palmitic acids. The biomass was subjected to an acid pre-treatment for the saccharification of complex carbohydrates, and the hydrolyzed biomass was fermented by Saccharomyces cerevisiae. It was possible to produce 0.615 ml g-1 of ethanol. In conclusion, D. tertiolecta has the potential for bioethanol production, making it a promising option for the biofuels future.
Eucalyptus pellita has been posited as a primary raw material in Indonesia due to its fast growth. In some areas, however, trees with heart rot were found. Thus, the wood with heart rot was analysed chemically both in sound (sapwood, outer heartwood, inner heartwood) and degraded parts (heart rot-affected wood/HRAW). The results revealed that there was a different trend in the wood chemical composition between bottom and centre parts. In bottom parts, wood with bigger diameter of heart rot, the slight changes in polysaccharides and lignin amounts was observed in HRAW compared to sound wood parts. On the contrary, comparatively high lignin and low polysaccharide levels in HRAW were measured in centre parts. HRAW was also characterized with high content of inorganic materials and high pH values but low in extractive content, mostly ethanol soluble extractives or its polar fraction. Increasing of phenolic contents was more pronounced in HRAW of lower part than that of upper of the stem. The difference trend of chemical composition between bottom and centre parts suggesting the cause of heart rot could be several wood degraders.
This document summarizes a study that investigated the effects of drum rotation speed and steam pressure on properties of drum-dried pitaya (dragon fruit) peel powder. Pitaya peel is typically discarded but contains antioxidants, fiber and betacyanin pigments. The study dried pitaya peel using a laboratory drum dryer at rotation speeds of 1-3 rpm and steam pressures of 1-3 bar. Higher rotation speed increased yield percentage but also moisture content. Higher steam pressure decreased yield, moisture content and water activity. The best conditions for betacyanin retention and product stability were 1 rpm and 2 bar, yielding powder with 80.21 mg/g betacyanin and 10.66% moisture. Overall
The document discusses research on optimizing the extraction of rotenone from Derris elliptica roots. It aims to determine processing parameters that maximize the yield of rotenoids resin, rotenone content, and biological activity (LC50). Preliminary experiments identified suitable ranges for solvent type, solvent-to-solid ratio, and raw material particle size. A 2k factorial design was used to evaluate these parameters. Results showed ethanol extraction at a lower solvent ratio and smaller particle size maximized yields, while acetone extraction was best at a higher ratio and larger particle size. Verification experiments confirmed the optimized parameters.
Synthesis and Characterization of Polymeric Drug Binder from Tobacco WastePremier Publishers
In Indian agriculture, tobacco has a prominent place. So, it is but natural that tobacco waste or dust is generated at various stages of post-harvest processing of tobacco and also while manufacturing various products. As rational production and processing of tobacco plant must include the entire biomass, both the main product leaves as well as stalks that remain after harvest. Residues (stalks and small leaves) and significant amounts of leaf scrap and waste generated during processing of tobacco, can serve as a very important secondary raw material from after final processing, a great number of products could be obtained in industry considering that these stalks contain a certain amount of cellulose. The waste obtained after nicotine extraction was utilized for cellulose extraction. The extracted cellulose was converted to value-added product such as cellulose acetate. Prepared cellulose acetate is characterized by Fourier transform infrared spectroscopy (FTIR).
A comparative study of biopolymers and alum in the separation and recovery of...Soumyadeep Mukherjee
This study compares the effectiveness of various biopolymers and alum in recovering pulp fibers from paper mill wastewater through flocculation. Guar gum was found to be the most effective biopolymer, recovering 3.86 mg/L of fibers. Alum displayed the highest particle removal rate. Guar gum, alum, xanthan gum, and locust bean gum removed 94.68%, 97.46%, 92.39%, and 92.46% of turbidity, respectively, at a settling velocity of 0.5 cm/min. Response surface methodology was used to optimize conditions like pH, dose, and mixing speed to obtain the lowest sludge volume index for guar gum. The results indicate similar performance
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
This study evaluated the effectiveness of low-cost biosorbents for removing methylene blue dye from aqueous solutions. Coconut fiber, banana fiber, and sawdust were tested individually and in combinations under stirring and stagnant conditions. The results showed that sawdust removed 99% of dye under stirring and 99.5% under stagnation. Continuous addition of biosorbents removed more dye (99%) than batch or fed-batch methods. A mixed biosorbent of sawdust, banana fiber, and coconut fiber removed over 98% of dye from solutions with concentrations up to 0.4 mg/mL. Lengthy coconut fibers removed 99.5% of dye within 48 hours under stagnant conditions.
IRJET - Novel Method of Lignin Separation from Almond Shells Applying Multipl...IRJET Journal
This document presents a novel method for isolating lignin from almond shells using multiple solvent contacts. Almond shells were treated with various solvent combinations in a reflux setup, including ethanol-water and 3% NaOH solution. FTIR analysis showed the isolated lignin samples matched literature lignin spectra. Two-stage contacting with 3% NaOH solution at both stages yielded the highest lignin amount at 28.33%, concluding it is the most effective isolation method. The study demonstrates the potential for utilizing almond shell waste through lignin extraction.
Textile industries produce huge amounts of polluted
effluents, whereby over 80% of textile dyes are constituted of
Benzedrine based dyes or aromatic hazardous substances azo
groups that are normally discharged to surface and ground water
aquifers. Through the scientific awareness to reach an ecofriendly
system, this research part deals on the optimum
extraction condition of the new neem natural dye, where the
optimization parameters have technical and commercial
importance on cost and color yield. This has been carried out
using water and different concentrations of water-acetone and
water ethanol mixtures at different temperatures, pH values and
time intervals. Data observed that the optimum extraction
condition was achieved with 50% (v/v) acetone, 18% (w/v) neem
amount at pH 9 at 70oC for 60 min where 50% (v/v) wateracetone
exhibited 60 % absorbance percentage compared to (31
and 9) % of 40% (v/v) water-ethanol and water respectively. The
absorbance values are influenced by the properties of solvents
such as, the dipole moment, dielectric constant, and refractive
index values. Aqueous extraction gave less amount of pigment
and was time consuming, promoting the degradation of color
compounds while the other co-solvents increased the extract
solubility, giving high extraction capacity. pH 9 increased the
diffusion coefficients of color component and the temperature at
70oC for 60 min enhanced the de-aggregation of its molecules.
Finally, FTIR analysis investigated the presence of mainly yield
quercetin (flavonoid) compounds in neem extract which is known
to have antibacterial and antifungal properties giving chance to
be applied for antimicrobial textile dyeing in the second part of
this study.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Effect of fast CO2 pressure changes on the yield of lovage (Levisticum offici...Egidijus Dauksas
1) The study investigated the effect of fast CO2 pressure changes on the extraction yield of compounds from lovage and celery plants.
2) It was found that applying frequent pressure changes in the extraction vessel increased the rate of extracting CO2-soluble materials from different parts of lovage and celery plants, compared to constant pressure extraction.
3) However, after sufficient CO2 had passed through the system, the total extraction yields were similar regardless of using constant or fluctuating pressures. The composition of extracts was analyzed and key compounds were identified.
Mass Transfer, Kinetic, Equilibrium, and Thermodynamic Study on Removal of Di...Ratnakaram Venkata Nadh
Three distinct agricultural waste materials, viz., casuarina fruit powder (CFP), sorghum stem powder
(SSP), and banana stem powder (BSP) were used as low-cost adsorbents for the removal of toxic lead(II)
from aqueous solutions. Acid treated adsorbents were characterized by scanning electron microscopy (SEM),
energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). The
effects of parameters like adsorbent dose, pH, temperature, initial metal ion concentration, and time of
adsorption on the removal of Pb(II) were analyzed for each adsorbent individually and the efficiency order
was BSP > SSP > CFP. Based on the extent of compatibility to Freundlich/Langmuir/Dubinin–Radushkevich/
Temkin adsorption isotherms and different models (pseudo-first and second order, Boyd, Weber’s, and
Elovich), chemisorption primarily involved in the case of BSP and SSP, whereas simultaneous occurrence of
chemisorption and physisorption was proposed in the case of CFP correlating with the thermodynamic study
results conducted at different temperatures. Based on the observations, it was proposed that three kinetic
stages involve in the adsorption process, viz., diffusion of sorbate to sorbent, intra particle diffusion, and then
establishment of equilibrium. These adsorbents have a promising role towards the removal of Pb(II) from
industrial wastewater to contribute environmental protection
Tea (Camellia sinensis) Waste for the reduction of Malathion and Phorate in ...Agriculture Journal IJOEAR
Abstract— Diminution of Malathion and Phorate from aqueous solutions by tea waste biomass was examined in a batch experimental setup. Waste tea powder, obtained from University canteen, S.V. University, Tirupati, India has been used as an effective material for the reduction of Malathion and Phorate from aqueous solutions. Characterization of the adsorbent was studied using SEM micrograph and Fourier Transform Infrared spectral analysis. From the FTIR spectrum it is observed that the change in peak position at 3390 cm−1 in the spectrum of the Phorate and Malathion loaded tea powder indicates the binding of these pesticides with hydroxyl groups. The working solutions of the pesticides are in the range of 0.1µg – 1.0µg for Malathion and 0.05µg – 0.5µg for phorate. It was observed that percentage adsorption increased with pH of the liquid phase and reached an optimum value of 95 % for Malathion and 94 % for phorate at pH 7.4 ± 0.2 and pH 7.5 ± 0.2, respectively. The dosage of the adsorbent had showed considerable effect on the adsorption of Malathion and Phorate.
Applications of Ultrasound to modify and dried fruitsPoojaHorti
This document discusses applications of ultrasound to modify and improve dried fruits. It begins with definitions of ultrasound and discusses fruits that are suitable for drying. It explains that ultrasound drying can reduce energy consumption and drying times for fruits compared to conventional drying methods. Various ultrasound drying methods are described, including ultrasound-assisted convective drying, osmotic dehydration, vacuum drying, and freeze drying. Case studies demonstrate how ultrasound pretreatments and drying can increase the drying rate of fruits like strawberries, improve the quality of dried fruits, and retain polyphenols in apples. The conclusion is that ultrasound is effective for accelerating fruit drying processes and maintaining fruit quality compared to conventional drying.
An Experimental Investigation on Treatment of Tannery Effluent Using Azadirac...IJEAB
A preliminary investigation was carried out for the feasibile use of Azadirachta indica leafs powder as a natural coagulant to the treatment of tannery effluent. In this paper, Azadirachta indica leafs powder of 1, 2, 3 and 4mg/L dosages were used. Floc formation in coagulation process had been studied in the laboratory scale to determine the optimum dosage of natural coagulant. The above dosages were used in pre-treated tannery effluent with coagulants were considered to evaluate the percentage removal efficiency on the major pollutants of concern in in tannery effluent such as turbidity, TSS, TDS, COD and BOD. From the observed results, dosage of 3 mg/L gives better removal efficiencies with respect to turbidity, TSS, TDS, COD and BOD and appears to be suitable for tannery effluent treatment, when compared with other dosages.
The development of sustainable bioplastics for new applications in packaging ...Agriculture Journal IJOEAR
Abstract— The advantage of biodegradable plastics is their degradation under the influence of biological systems into substances naturally present in the environment, which are then placed in a natural circulation cycle of matter. Moreover, the biodegradable plastics waste not require additional segregation and separation from households, and are collected together with other organic waste and subjected to recycling under aerobic or anaerobic conditions. Use of bioplastics reduces the harmful effects of waste on the environment, but does not eliminate it completely.
The article presents the results of (bio) degradation studies under industrial and laboratory (MicroOxymax) composting conditions as well as at atmospheric conditions of commercial disposable dishes from the Nature Works® PLA. Were also carried out investigation of abiotic degradation under laboratory conditions. It was found, from the macro- and microscopic observations, that the tested cups (bio) degraded in the selected environments, wherein in a greater extent under industrial composting conditions than in MicroOxymax. The GPC results, which show significantly reduce in the molar mass of the tested samples after specified incubation times in all environments, indicates that the hydrolytic degradation process occurs predominantly.
Statistical Modelling of Drying Characteristics of Unripe Plantain (Musa Para...Dr. Amarjeet Singh
This work is designed to carry out the statistical modelling of the drying characteristics of unripe plantain (Musa paradisiaca) slices and to study the effect of drying temperature and slice thickness on drying characteristics. The test samples were dried in a laboratory scale oven dryer at varying temperatures of 700C, 800C and 900C, and different slice thicknesses of 2mm, 3mm and 4mm.The result obtained indicated that drying temperature and slice thickness had significant effect on drying rate and hence moisture profile. The moisture ratio – drying time data obtained were fitted to ten thin layer drying models. The fit quality obtained with each model was evaluated using statistical tests namely; coefficient of determination (R2), root mean square error (RMSE), reduced chi-square (X2), and standard error of estimate (SEE). Although most of the models fitted quite well to the experimental data, Page and Modified Page models showed the highest average R2 and the lowest average RMSE, X2 and SEE values. Page and modified Page models were selected and found suitable to represent the drying characteristics of unripe plantain slices and predict drying times.
This document discusses optimization and kinetic studies on extracting oil from the marine macroalgae Ulva lactuca for biodiesel production. Six pre-treatment methods were tested to disrupt the algal cells and increase oil extraction efficiency. Parameters like moisture content, particle size, temperature, and solvent composition were optimized to obtain a high oil yield of 10.88% from 30g of algal biomass. Kinetic studies using a first order model determined the extraction has an activation energy of 63.031 kJ/mol. The results show U. lactuca is a suitable feedstock for biodiesel production.
OPTIMIZATION OF SOME MINERAL CONTENTS OF DRIED OSMO-PRETREATED GREEN BELL PEP...Oyeniyi Samuel
This document summarizes a study that used Response Surface Methodology to optimize the mineral content of dried osmotically pretreated green bell peppers. Bell peppers were treated with varying concentrations of salt solutions for different durations, then dried. The mineral contents of magnesium, potassium, and manganese were analyzed. Optimization found the maximum magnesium content was 29.18 mg/100g with 25% salt solution for 180 minutes, maximum potassium was 46.13 mg/100g with 5% salt for 60 minutes, and maximum manganese was 10.96 mg/100g with 15% salt for 150 minutes. Pretreated dried peppers had higher mineral contents than untreated dried peppers.
Antioxidant activity of hedera helix l. extracts and the main phytoconstituentspharmaindexing
This document summarizes a study that evaluated the antioxidant activity of extracts from Hedera helix stems and identified phytochemicals in the most active extract. Ethyl acetate, methanol, dichloromethane and n-hexane extracts were tested for antioxidant effects using DPPH radical scavenging assays. The ethyl acetate extract showed the highest antioxidant activity at 84.95% due to compounds like flavonoids, tannins and triterpenes. Phytochemical analysis confirmed the presence of these compounds in the ethyl acetate extract, suggesting they contribute to its antioxidant properties.
This document describes a study comparing the acetylation of cellulose extracted from Eucalyptus Camaldulensis Dehn wood using microwave irradiation versus conventional heating. Cellulose was acetylated using acetic anhydride with pyridine as a catalyst. The reaction was performed using microwave irradiation for 6 hours and conventional heating for 7 hours. The acetylated products were characterized using FT-IR spectroscopy. The results showed that microwave irradiation led to a faster and cleaner reaction compared to conventional heating. Microwave irradiation is proposed as a more efficient method for acetylating cellulose.
Abstract— Biofuel production from microalgae biomass appears as a promising long term alternative. Dunaliella tertiolecta is a microalgae with high tolerance to salinity, temperature, and light, making it relatively easy to grow. The aim of this study was to establish a pilot-scale culture to evaluate the biomass yield and bioethanol production. The cell culture of D. tertiolecta was started in 20 ml tubes and escalated to 20 L containers. The biomass yield was 0.153 g L-1 of dry basis (db) and its characterization showed protein (37% db) as major component followed by carbohydrates (35.6), lipids (13% db) and ash (6.5%). The carbohydrate fraction was composed of starch (27.1% db) and fiber (8.5 %) and its neutral sugar characterization yield glucose (91% molar). The main components of the lipid fraction were linolenic and palmitic acids. The biomass was subjected to an acid pre-treatment for the saccharification of complex carbohydrates, and the hydrolyzed biomass was fermented by Saccharomyces cerevisiae. It was possible to produce 0.615 ml g-1 of ethanol. In conclusion, D. tertiolecta has the potential for bioethanol production, making it a promising option for the biofuels future.
Eucalyptus pellita has been posited as a primary raw material in Indonesia due to its fast growth. In some areas, however, trees with heart rot were found. Thus, the wood with heart rot was analysed chemically both in sound (sapwood, outer heartwood, inner heartwood) and degraded parts (heart rot-affected wood/HRAW). The results revealed that there was a different trend in the wood chemical composition between bottom and centre parts. In bottom parts, wood with bigger diameter of heart rot, the slight changes in polysaccharides and lignin amounts was observed in HRAW compared to sound wood parts. On the contrary, comparatively high lignin and low polysaccharide levels in HRAW were measured in centre parts. HRAW was also characterized with high content of inorganic materials and high pH values but low in extractive content, mostly ethanol soluble extractives or its polar fraction. Increasing of phenolic contents was more pronounced in HRAW of lower part than that of upper of the stem. The difference trend of chemical composition between bottom and centre parts suggesting the cause of heart rot could be several wood degraders.
Preparation and Characterization of Activated Carbon from Hura Crepitans Linn...theijes
Activated carbons were thermally prepared from Hura Crepitan L. seed shells. Zinc chloride (ZnCl2) and Phosphoric acid (H3PO4) were separately used as the activating agents. The activated carbons obtained were characterized by determining the percentage yield, moisture content, ash content and percentage fixed carbon. The adsorption of methylene blue by the activated carbon was done using 0.1 to 0.5g of the activated carbon. The results revealed that the percentage yield and ash content of H3PO4 impregnated activated carbon was higher than ZnCl2 impregnated activated carbon. On the other hand ZnCl2 impregnated activated carbon had higher moisture content and percentage fixed carbon. It was also revealed that ZnCl2 impregnated activated carbon had greater adsorption capacity than H3PO4 impregnated activated carbon. However it was found that the higher the adsorbent (activated carbon) dosage, the higher the adsorption capacity.
1) The study investigated the polyphenolic content of rose hip (Rosa canina L.) tea extracts obtained using ultrasound-assisted extraction (UAE) and Soxhlet extraction with different solvents.
2) The highest extract yield was obtained using UAE with water at 619.37 mg/g dried matter. The highest total phenolic content was obtained using Soxhlet extraction with a 50% methanol mixture at 59.69 mg gallic acid equivalent/g dried matter.
3) UAE and Soxhlet extraction with various solvents, including water, ethanol, methanol, and mixtures, were tested on three commercial brands of rose hip tea. Total phenolic content and extract yields
This document describes the development of a solid phase microextraction-gas chromatography (SPME-GC) method to analyze the compounds released from Eucalyptus camaldulensis (River Red Gum) leaves and track this dissolved organic carbon (DOC) in aquatic environments. The researchers optimized the SPME extraction conditions using standards representative of compounds likely present in River Red Gum leaf leachate. They then applied the optimized method to analyze artificial DOC solutions prepared from River Red Gum leaf leachate to demonstrate the potential of the method for fingerprinting and tracing natural DOC sources in rivers.
This document summarizes a study on the biosorption of styrene from wastewater using sugarcane waste (bagasse) as an adsorbent. Equilibrium isotherms and kinetics were determined for the biosorption process. The effects of parameters like temperature, pH, particle size, and bagasse concentration on biosorption were examined. The maximum styrene uptake of 88% was achieved at pH 12.1, temperature of 35°C, particle size of 420-500 μm, and bagasse concentration of 1 g/L. Adsorption equilibrium data fit the Langmuir and Freundlich isotherm models well. Kinetics followed pseudo-second order kinetics. Increased temperature
The document reports on a study of extracting passion fruit seed oil using supercritical CO2. Experimental data was collected for extraction conducted at varying pressures, temperatures, and CO2 flow rates. An increase in pressure, temperature, and flow rate increased the extraction yield, with a maximum yield of 18.5% obtained. Mass transfer coefficients for passion fruit oil were determined to be 8.496 x 10-5 s-1 at specific conditions. Rheological studies observed dilatant fluid behavior in all tests. Bayesian inference was used to model mass transfer and account for parameter uncertainty.
Sorption kinetics and equilibrium studies on the removal of toxic cr(vi) ions...Alexander Decker
This document summarizes a study on using modified Indian almond nut shells to remove toxic chromium (CrVI) ions from aqueous solutions. Characterization of the nut shells showed they have good surface area and pore properties for adsorption. Batch experiments were conducted to determine the effects of various parameters on CrVI removal, including nut shell particle size, contact time, initial concentration, sorbent dose, and pH. Adsorption kinetics and equilibrium were analyzed using common isotherm models. The modified nut shells were found to effectively remove CrVI from solutions, with optimized parameters being a particle size of 0.18mm, sorbent dose of 200mg, initial concentration of 11mg/L, contact time of 30 minutes
Sorption kinetics and equilibrium studies on the removal of toxic cr(vi) ions...Alexander Decker
This document summarizes a study on the removal of toxic chromium ions from aqueous solutions using modified Indian almond nut shells. Key findings include:
- Modified Terminalia catappa nut shell (TTCNS) was characterized and found to have mesoporous structure suitable for liquid phase adsorption. Maximum adsorption of chromium ions occurred with 0.18mm TTCNS particles.
- Batch experiments optimized parameters like contact time (30 minutes), pH (2), initial concentration (11 mg/L), and adsorbent dose (200 mg) for maximum chromium removal.
- Adsorption kinetics followed pseudo-second order model and equilibrium data fit well with Langmuir isotherm model,
The document discusses using low-cost walnut shells to remove two common pesticides, carbofuran and chloropyriphos, from aqueous solutions. Walnut shells were treated chemically and thermally to increase their surface area and porosity for effective adsorption. Batch and column adsorption methods were used to study the adsorption of pesticides under different conditions. Adsorption parameters like pH, contact time, concentration, and kinetics were analyzed. The treated walnut shells showed high adsorption capacity of 97-99% within 30 minutes. The adsorption process was found to be dependent on pH. The document also characterized the adsorbent material using SEM, FT-IR, and surface area analysis
Production of Biofuels from the Seeds and Waste of the Mexican Poppy adoniaanastas
This document summarizes research on extracting both esters and biogas from Mexican poppy (Argemone mexicana). Key findings include:
- A. mexicana seed contains 30% oil that can be converted to methyl ester through transesterification, producing 1000 ml of ester and 200 ml of glycerol from 1 L of oil. Methanol gave better ester separation than ethanol.
- The calorific value of A. mexicana seed waste was 4621 Kcal/Kg with a C/N ratio of 11. Biogas production under sunlight was 10 times higher than at room temperature. Biogas contained 52% methane.
- Physical properties of the
The chemical separation is used to reduce the quantity of potentially toxic or hazardous materials discharged to the environment. In addition, separations that lead to recycle, recovery, or reuse of materials also prevent discharge. It is can assists in resolving some of the environmental challenges, so it became more important for researchers, in particular, environmental specialists. Hence, this article aimed to collection information about the chemical separation to help the researchers to resolve the environmental problems. Overall, it can concluded that the extraction is the first step to separate the desired substance from the raw materials and there are various methods for extraction such as sublimation, distillation method and solvent extraction. Correspondently, there are many types of separation processes, the most widely used method is the chromatography method.
International Refereed Journal of Engineering and Science (IRJES)irjes
This document summarizes a study investigating the adsorption capacity of activated carbon prepared from palm kernel shell for removing methylene blue dye from aqueous solution. The palm kernel shell was carbonized and activated to produce porous activated carbon. Testing showed the activated carbon had a surface area of 127 m2/g and micropore volume of 0.11 cm3/g. Adsorption experiments were conducted with methylene blue solutions and found that 94-80% of the dye was adsorbed within 10 minutes, with maximum adsorption reached at 50 minutes. Equilibrium adsorption data fit well to the Langmuir isotherm model, with a maximum adsorption capacity of 3.22 mg/g predicted by the model
Isolation and characterization of steroids from petroleum ether extract of st...Alexander Decker
1. Three steroids were isolated from the stem bark of Parinari curatellifolia through a series of column chromatographies.
2. The steroids were characterized as β-sitosterol, stigmast-4-en-3-one, and stigmasterol based on NMR, MS, and IR spectroscopy.
3. This is the first report of these steroids being isolated from P. curatellifolia.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
IRJET- Removal of Acetaminophen from Waste Water using Low Cost AdsorbentIRJET Journal
The document summarizes a study on removing the pharmaceutical acetaminophen from wastewater using low-cost adsorbents developed from agricultural waste. Activated carbons were prepared from banana leaves, garlic stems, and babool seeds. The maximum removal efficiency of 84.9% was achieved using activated banana leaves adsorbent. Kinetic studies showed activated banana leaves adsorbent achieved removal equivalent to commercial activated carbon. Therefore, activated banana leaves have potential to be a good low-cost adsorbent for removing acetaminophen from wastewater.
IRJET- Hydrothermal Pretreatment Enhanced Enzymatic Hydrolysis and Glucose Pr...IRJET Journal
This document summarizes a study that investigated the use of hydrothermal pretreatment to enhance the enzymatic hydrolysis and glucose production from lignocellulosic biomass. Specifically:
- Sawdust samples from hardwood and softwood were treated with sodium hydroxide solution at 80±5°C for varying times. The 180 minute treatment yielded the highest cellulose content (84.9% for hardwood, 83.5% for softwood) and lowest lignin content.
- The pretreated samples were then hydrolyzed with crude enzymes from Trichoderma and Aspergillus niger fungi. The maximum glucose yields were 7.4% and 6% respectively.
- Total solid
The document discusses several pesticides and fungicides used in crop protection, including their names, chemical formulas, mechanisms of action, and physical properties. It provides information on Diels-Alder reactions, endosulfan, malathion, dimethoate, pyrethroids, mancozeb, chlorothalonil, and considerations for 1st and 2nd generation pesticides.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
2. 106
R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
Fig. 1. Main triterpenic acids identified in E. globulus bark.
particular, SC-CO2 has been successfully employed in the extraction of numerous vegetable matrices [15,16,28–35] mainly due
to its favorable transport properties [36–40] and tunable solvent
strength, allied to low price and non-toxicity. Several reviews on
the SFE modeling and applications have been published over the
years [34,35,41,42].
The SC-CO2 has been successfully applied in the extraction of
triterpenes from several vegetable raw materials as, for instance,
betulin from the bark of Betula platyphylla [25] or ursolic and
oleanolic acids from the seeds of Plantago major L. [26]. We have
recently published [14] some preliminary results on the SFE of
TTAs from E. globulus deciduous bark with pure and modified CO2 ,
where it is demonstrated the chief influence of pressure and the
important role played by ethanol (cosolvent) upon the extraction
yields. Regarding the same species, a detailed study using pure SCCO2 has been also published, where the influence of solubility is
modeled and specifically focused [15]. The kinetic behavior of the
SFE of E. globulus has been also addressed in a different paper [16],
where extraction curves were measured and modeled using simple
expressions from the literature in order to devise the relevant mass
transfer limitations of the process.
These results induced us to carry out a detailed experimental
programme with the objective of evaluating the individual and
combined effects of the SFE operating conditions (pressure, temperature, and cosolvent content) upon the yield and quality of the
extracts of E. globulus deciduous bark. Such quality was measured
in terms of the concentration of TTAs in the final extracts. For this
purpose, a design of experiments (DOE) was followed in order to
identify the main factors and interactions influencing the measured
responses. The response surface methodology (RSM) was adopted
to establish validated response functions.
2. Materials and methods
2.1. Bark samples
Deciduous bark of E. globulus was randomly harvested from
a 20-year-old clone plantation cultivated in Eixo (40◦ 37 13.56 N,
8◦ 34 08.43 W), region of Aveiro, Portugal. The bark was then dried
in an oven at 40 ◦ C during approximately 72 h, reaching final moisture content between 2 and 5%, milled to granulometry lower than
2 mm prior to extraction, and stored in hermetically sealed bags
until use. Deciduous bark was selected as substrate, since it is
mostly outer bark (which favors the TTAs concentration) and avoids
felling a large number of trees to ensure a continuous supply of raw
material of controlled origin for a long-term study.
2.2. Chemicals
Nonacosan-1-ol (98% purity) and ˇ-sitosterol (99% purity)
were purchased from Fluka Chemie (Madrid, Spain); ursolic
acid (98% purity), betulinic acid (98% purity), and oleanolic
acid (98% purity) were purchased from Aktin Chemicals
(Chengdu, China); betulonic acid (95% purity) was purchased
from CHEMOS GmbH (Regenstauf, Germany); palmitic acid
(99% purity), dichloromethane (99% purity), pyridine (99%
purity),
bis(trimethylsilyl)trifluoroacetamide
(99%
purity),
trimethylchlorosilane (99% purity), and tetracosane (99% purity)
were supplied by Sigma Chemical Co. (Madrid, Spain). Carbon
dioxide was supplied with a purity of 99.95% from Praxair (Porto,
Portugal).
2.3. Soxhlet extraction
Samples of E. globulus deciduous bark (around 25 g) were
Soxhlet-extracted with dichloromethane for 7 h. The solvent was
evaporated to dryness, the extracts were weighed, and the results
were expressed in percent of dry bark. The results from Soxhlet
extraction were used as reference to measure the efficiency of the
supercritical extractions. Dichloromethane was chosen because it
is a fairly specific solvent for lipophilic extractives.
2.4. Supercritical fluid extractions
Supercritical extraction experiments were performed in an
apparatus purchased from Applied Separations (USA) (see
Fig. S1 in Supplementary Data). In this system, the liquid CO2 taken
from a cylinder is compressed to the desired extraction pressure
by means of a cooled liquid pump after which it goes through a
Coriolis mass flow meter used to measure the CO2 flow rate. The
liquid stream is then heated to the operating temperature in a
vessel placed before the extractor column. The solvent in the supercritical state then flows through the extractor where the sample
was previously loaded. Afterwards, the effluent from the extractor is depressurized in a heated backpressure regulator valve and
bubbled in ethanol to capture the extract for subsequent GC–MS
analysis. The spent CO2 is vented to the atmosphere. The addition
of cosolvent to the system is accomplished by a liquid pump (LabAlliance Model 1500) coupled to the gas line between the mass flow
meter and the heating vessel placed before the extractor column, in
order to mix both CO2 and cosolvent before feeding the extraction
vessel. The cosolvent flow rate is controlled by the liquid pump.
In each run, 70–80 g of milled bark was introduced in the extraction vessel. A constant CO2 mass flow rate of 6 g min−1 was used in
all extractions during 6 h, totalizing 2.2 kg of spent carbon dioxide.
Table 1 lists the remaining experimental conditions: temperature,
T, pressure, P, and cosolvent (ethanol:EtOH) added to CO2 . The solvent was evaporated first in a rotary evaporator, then in a nitrogen
stream and finally in a vacuum oven at 60 ◦ C for 6 h. The extracts
were weighed and the results expressed in percentage of dry bark.
3. R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
Table 1
Codification and levels of the three independent variables considered for the SFE
factorial design of experiments.
Variable
Level correspondence
Low (−1)
Pressure (XP )
Temperature (XT )
Ethanol content (XEtOH )
Medium (0)
High (+1)
100 bar
40 ◦ C
0.0%
150 bar
50 ◦ C
2.5%
200 bar
60 ◦ C
5.0%
2.5. Design of experiments and response surface methodology
RSM is a useful used tool for analyzing the relationships between
measured responses (dependent variables) and factors (independent variables), allowing to minimize experimentation and leading
to correlations that can be used for optimization purposes [43],
mainly when rigorous modeling is difficult to apply. In recent years
it is being adopted to the SFE of solutes from distinct matrixes (e.g.,
references [12,44,45]).
In this work, it was studied the influence of temperature
(40–60 ◦ C), pressure (100–200 bar) and cosolvent addition (0–5%
wt.) upon the extraction yield, triterpenic acids recovery, and their
respective concentrations in extracts. The remaining independent
variables (e.g., solvent flow rate, extraction time, and bark particle
size) were kept constant during the experimental procedures. In
Table 1, the levels of the independent variables under investigation
are listed. In the whole, 26 experiments have been carried out in
this essay. Nonetheless, in order to perform with advantage a full
33 factorial design of experiments, 6 results from a previous publication [15] have been also included to complement and enrich the
statistical analysis of our work.
The three levels defined in Table 1 for each factor were codified
according to Eq. (1), so that their ranges of variation lie between −1
and 1:
Xk =
xk − x0
xk
(1)
where Xk is the coded value of the independent variable xk , x0 is its
real value at the center point, and xk is the step change in variable
k. In a system involving three significant independent variables, the
mathematical relationship of each response on these variables is
approximated by the general quadratic polynomial:
2
2
2
Y = ˇ0 + ˇ1 XP + ˇ2 XT + ˇ3 XEtOH + ˇ11 XP + ˇ22 XT + ˇ33 XEtOH
+ ˇ12 XP XT + ˇ13 XP XEtOH + ˇ23 XT XEtOH
(2)
where Y is the response, ˇ0 is a constant, ˇ1 , ˇ2 and ˇ3 are the
linear coefficients, ˇ12 , ˇ13 and ˇ23 are the interaction or crossed
coefficients, and ˇ11 , ˇ22 and ˇ33 are the quadratic coefficients.
STATISTICA software (version 5.1, StatSoft Inc., Tulsa, USA) was
used for statistical treatment of the results. Analysis of variance
(ANOVA) was employed to assess the statistically significant factors
and interactions using Fisher’s test and its associated probability p(F), while t-tests were performed to judge the significance
of the estimated coefficients in each model. The determination
2
coefficients, R2 , and their adjusted values, Radj , were used to evaluate the goodness of fit of the regression models.
In order to check the reproducibility of our experiments and the
applicability of the models for subsequent predictions, additional
runs were performed: (i) replicates at [200 bar, 60 ◦ C, 0.0% EtOH;
runs 32 and 33 in Table 2] and [200 bar, 60 ◦ C, 5.0% EtOH; runs
34 and 35 in Table 2] for the reproducibility assessment, and one
run at [170 bar, 50 ◦ C, 2.5% EtOH, run 31, see Table 2] to construct
the validation set of the model. This set includes also three experiments retrieved from previous work [15], at [140 bar, 0% EtOH, and
40/50/60 ◦ C; runs 28–30 in Table 2].
107
2.6. GC–MS analyses
Before each GC–MS analysis, nearly 20 mg of dried sample were
converted into trimethylsilyl (TMS) derivatives according to the literature [11]. GC–MS analyses were performed using a Trace Gas
Chromatograph 2000 Series equipped with a Thermo Scientific
DSQ II mass spectrometer, using helium as carrier gas (35 cm s−1 ),
equipped with a DB-1 J&W capillary column (30 m × 0.32 mm i.d.,
0.25 m film thickness). The chromatographic conditions were as
follows: initial temperature: 80 ◦ C for 5 min; temperature rate of
4 ◦ C min−1 up to 260 ◦ C and 2 ◦ C min−1 till the final temperature
of 285 ◦ C; maintained at 285 ◦ C for 10 min; injector temperature:
250 ◦ C; transfer-line temperature: 290 ◦ C; split ratio: 1:50. The MS
was operated in the electron impact mode with electron impact
energy of 70 eV and data collected at a rate of 1 scan s−1 over a
range of m/z 33–700. The ion source was maintained at 250 ◦ C.
For quantitative analysis, the GC–MS instrument was calibrated with pure reference compounds, representative of the
major lipophilic extractives components (namely, palmitic acid,
nonacosan-1-ol, ˇ-sitosterol, betulinic acid, ursolic acid and,
oleanolic acid), relative to tetracosane, the internal standard used.
The respective multiplication factors needed to obtain correct
quantification of the peak areas were calculated as an average of
six GC–MS runs. Compounds were identified, as TMS derivatives,
by comparing their mass spectra with the GC–MS spectral library
(Wiley, NIST Mass Spectral Library 1999), with data from the literature [11,46,47] and, in some cases, by injection of standards.
Each sample was injected in triplicate. The results presented are
the average of the concordant values obtained for each sample (<5%
variation between injections of the same sample).
3. Results and discussion
The main objective of this work is to study the SC-CO2 extraction of E. globulus deciduous bark maximizing TTAs yield and
their concentration in extracts. Taking into account the structures of the TTAs (Fig. 1), particularly the different polarities
between free TTAs (ursolic, oleanolic, betulinic, and betulonic
acids) and acetylated TTAs (3-acetylursolic, 3-acetyloleanolic acids
and 3-acetylbetulinic), they exhibit distinct solubilities in SC-CO2 .
Accordingly, five responses of interest were studied in parallel
based on the 33 full factorial DOE, specifically total extraction yield,
TTAs yield, their respective free and acetylated yields, and TTAs
concentration.
The results of the 35 SFE runs considered in this work are collected in Table 2, along with the three independent variables in
coded form. Globally, there are 21 new experiments for the DOE, 4
for reproducibility test, and 1 for the validation of the models; the
remaining 6 results were taken from de Melo et al. [15].
Within the experimental space considered, the total extraction
yield ranged from 0.04% (wt.) in run 7 [100 bar, 60 ◦ C, 0% EtOH] to
1.2% (wt.) in run 21 [200 bar, 40 ◦ C, 5% EtOH]. Regarding the extraction of TTAs, experimental runs led to a minimum of 0.05 g/kg of
bark and a maximum of 4.95 g/kg of bark, which correspond to 0.7
and 76.8% of the reference value measured by conventional Soxhlet,
respectively. The TTAs concentration in the extracts ranged from
5.7% in runs 4 [100 bar, 50 ◦ C, 0% EtOH] and 16 [100 bar, 60 ◦ C, 2.5%
EtOH] to 43.0% and 43.1% obtained in runs 27 [200 bar, 60 ◦ C, 5%
EtOH] and 24 [200 bar, 50 ◦ C, 5% EtOH], respectively.
In order to investigate the main factors and interactions influencing the five responses of interest, and to evaluate their trends
upon variation of the factors within the ranges considered, polynomial regressions were fitted following the RSM. The regression
coefficients obtained for each response using coded variables, are
listed in Table 3. The statistically significant coefficients at 95%
4. 108
R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
Table 2
Results of the SFE of E. globulus bark samples considered in this work.
Exp
Objectivea
XP
XT
XEtOH
Extraction yield (%, wt.)
Yield TTA (mg/kgbark )
TTA concent. (%, wt.)
Free
1b
2
3b
4b
5
6b
7b
8
9b
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28b
29b
30b
31
32
33
34
35
a
b
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
DOE
Valid.
Valid.
Valid.
Valid.
Reprod.
Reprod.
Reprod.
Reprod.
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−1
0
1
−0.2
−0.2
−0.2
0.4
1
1
1
1
−1
−1
−1
0
0
0
1
1
1
−1
−1
−1
0
0
0
1
1
1
−1
−1
−1
0
0
0
1
1
1
−1
0
1
0
1
1
1
1
−1
−1
−1
−1
−1
−1
−1
−1
−1
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
−1
−1
−1
0
−1
−1
1
1
Total
67.1
339.4
403.0
22.6
353.5
690.6
17.7
169.1
495.1
535.3
1252.8
1339.2
261.0
894.2
1330.6
26.4
738.4
1083.0
1164.5
1783.9
2744.2
747.8
1412.4
2285.5
136.2
1207.3
2227.5
296.7
286.7
176.8
1040.0
498.6
520.1
2000.5
2103.5
0.27
0.46
0.57
0.09
0.46
0.53
0.04
0.33
0.77
0.50
0.81
0.86
0.34
0.66
0.83
0.14
0.71
0.92
0.70
0.91
1.23
0.56
0.92
1.03
0.14
0.79
1.00
0.43
0.41
0.26
0.68
0.74
0.76
0.94
1.01
Acetylated
368.3
764.5
1437.3
28.4
729.9
1300.9
27.8
425.6
1044.7
1158.6
2080.0
1987.4
630.9
1461.8
2082.2
51.2
1390.5
1922.7
1715.7
1785.9
2205.1
1060.1
1599.1
2156.2
200.0
1436.0
2114.8
657.9
599.9
325.0
1368.4
998.2
1101.6
1811.2
1978.2
435.4
1103.9
1840.3
51.0
1083.4
1991.5
45.6
594.7
1539.7
1693.9
3332.8
3326.6
891.9
2356.0
3412.8
77.6
2128.9
3005.7
2880.3
3569.8
4949.4
1807.8
3011.6
4441.7
336.2
2643.3
4342.3
954.6
886.6
501.8
2408.4
1496.8
1621.7
3811.7
4081.7
16.12
23.89
32.04
5.67
23.62
37.61
11.39
18.02
20.00
33.92
41.35
38.84
26.12
35.67
40.97
5.71
29.85
32.56
41.15
39.14
40.24
32.28
32.66
43.12
24.02
33.37
43.00
22.2
21.6
19.3
35.4
20.1
21.2
40.5
40.4
DOE = design of experiments; Valid. = validation set; Reprod. = reproducibility set.
Retrieved from [15].
confidence level are highlighted in bold. Concerning the fitting adequacy, the obtained models represented well the experimental data
(R2 in the range of 0.857–0.983). The regression for the TTAs concentration was the only which led to determination coefficients
2
below 0.9, namely R2 = 0.857 and Radj = 0.782. If compared within
2
each response, the adjusted determination coefficients (Radj ), that
take into account both R2 and the degrees of freedom, did not differ notably from their corresponding R2 . It is known that when
2
R2 and Radj differ considerably the model is prone to include nonsignificant terms [43].
The coefficients that were not significant (t-test, 17 degrees of
freedom, p > 0.05) were removed from the general polynomial, Eq.
(2). Then the final models were refitted to data and converted to
uncoded variables, namely, extraction pressure (in bar), temperature (in ◦ C), and content of ethanol added to SC-CO2 (%, wt.).
The reduced experimental equations are shown in Table 4. In all
Table 3
Regression coefficients of the quadratic model given by Eq. (2), their individual significance at 95% confidence level, and respective determination coefficients for the full
model (FM). (Values in bold represent significant coefficients.)
Regressed
coefficients of Eq. (2)
Total extraction yield
TTAs extraction yield
Free TTAs
TTAs concentration
Acetylated TTAs
Total
FM
ˇ0
ˇ1
ˇ2
ˇ3
ˇ12
ˇ13
ˇ23
ˇ11
ˇ22
ˇ33
R2
R2 adj
p
FM
P
FM
p
FM
p
FM
p
0.688148
0.275556
−0.08167
0.208889
0.098333
0.0325
−0.0625
−0.08778
0.017222
−0.04111
<0.001
<0.001
<0.001
<0.001
<0.001
0.140
0.008
0.009
0.569
0.184
865.6926
534.45
−196.039
619.5111
75.48333
310.6167
−166.167
−40.2611
−14.7944
74.75556
<0.001
<0.001
<0.001
<0.001
0.047
<0.001
<0.001
0.430
0.770
0.152
1486.411
611.6833
−271.639
452.5278
201.3333
11.825
−73.6583
−103.017
0.95
−285.017
<0.001
<0.001
<0.001
<0.001
0.003
0.844
0.230
0.235
0.991
0.003
2352.211
1146.128
−467.794
1072.039
276.8
322.4667
−239.733
−143.45
−13.4833
−210.517
<0.001
<0.001
<0.001
<0.001
0.004
0.001
0.011
0.242
0.911
0.093
33.93259
7.333333
−4.93167
7.812222
2.875833
−2.29667
0.208333
−1.68778
−1.71278
−2.92444
<0.001
<0.001
0.001
<0.001
0.072
0.144
0.891
0.437
0.430
0.186
0.965
0.947
0.983
0.974
0.947
0.919
0.973
0.959
0.857
0.782
5. R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
109
Table 4
Reduced experimental models (RM) fitted to the responses of the 27 DOE runs of Table 2.
Response
Extraction yield
(%, wt.)
Free TTAs
(mg/kgbark )
Acetylated TTAs
(mg/kgbark )
Total TTAs
(mg/kgbark )
TTAs concentration
(mg/kgbark )
Equation
Reduced experimental models
2
R2
R2 adj
Y1 = 0.43343 − 0.031412T + 0.0062111P + 0.20826EtOH − 0.000035111EtOH + 0.000019667P −
0.0025000T EtOH
Y2 = 869.43 − 25.632T − 3.0717P + 207.40CoSolv − 6.6467T EtOH + 2.4849PEtOH
(3)
0.956
0.943
(4)
0.980
0.974
Y3 = 3224.0 − 87.564T − 7.8997P − 45.603EtOH2 + 409.02EtOH + 0.40267PT
(5)
0.938
0.923
Y4 = 3856.5 − 105.85T − 11.207P + 521.54EtOH + 0.5536PT − 9.5893T EtOH + 2.5797PEtOH
(6)
0.966
0.955
Y5 = 24.562 − 0.49317T + 0.14667P + 3.1249EtOH
(7)
0.780
0.751
Fig. 2. Response surfaces plotting the effects of pressure and temperature over: (a) total extraction yield, and (b) triterpenic acids yield, for 5% EtOH content. Dots are
experimental data, and surfaces are given by Eqs. (3) and (6) (Table 4), respectively.
models the individual factors (pressure, temperature and ethanol
content) revealed to be statistically significant. From the signal
of the coefficients, it may be figured out the positive or negative
impact of these factors upon the responses. In all cases, pressure
and ethanol addition favored the results, while temperature was
seen to unfavorably affect all responses. It is well known that an
isobaric increase of temperature decreases the SC-CO2 density, thus
reducing its solvent power. On other hand, the vapor pressure of
solutes increases with temperature, which increments their solubilities in the supercritical solvent. Taking into account that the
measured extraction yields evidence no enhancement with temperature (at the same pressure), it is possible to conclude that
in the range of our experimental conditions the density reduction prevails over vapor pressure increase. This behavior can be
seen in Fig. 2, where the total extraction (Fig. 2a) and the TTAs
(Fig. 2b) yields are plotted as functions of P and T for 5% EtOH
addition. However, this trend is more pronounced at low pressure
(100 bar) due to the large compressibility of CO2 near the critical point. At 200 bar this effect is much more attenuated but not
eliminated.
also confirms this assertion. This trend was also observed in the
other responses studied. All the independent variables (P, T, and
% EtOH) (p < 0.001, as well as the interactions P–T (p < 0.001) and
T–%EtOH (p < 0.008), affected the total extraction yield significantly
(see Table 3 or the reduced model (Eq. (3)) in Table 4).
3.1. Total extraction yield
Fig. 3 shows the fitted response surface for the total extraction
yield (Eq. (3) in Table 4) at 40 ◦ C, where dots represent experimental data. One may conclude that the regression model is in
good agreement with the lab results, which is also confirmed by
2
the determination coefficients found (R2 = 0.956 and Radj = 0.943).
The unbiased distribution of the points near the diagonal in Fig. 4,
where predicted yields are plotted against the measured values,
Fig. 3. Response surface showing the effect of pressure and ethanol content on the
total extraction yield at 40 ◦ C. Dots are experimental data, and surface is given by
Eq. (3) (Table 4).
6. 110
R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
As previously referred, both P and % EtOH have a positive effect
upon the extraction yield. By comparing the results measured at
200 bar and 0% EtOH (0.57%, wt.) and 100 bar and 5% EtOH (0.76%,
wt.), one conclude that 5% EtOH leads to an extraction enhancement
higher than that achieved by a 100 bar increment. This behavior
emphasizes the chief role played by cosolvent due to the polarity
modification imparted to the supercritical solvent.
Despite the apparent benefit of cosolvent upon the extraction
yield, it may increase the solubility of both valuable and nonvaluable compounds. For this reason, detailed responses regarding
TTAs extraction and their concentration will be analyzed in the next
sections.
3.2. Triterpenic acids extraction yield
Fig. 4. Measured versus predicted total extraction yield (%, wt).
The fitted surfaces and experimental data of the overall TTAs
extraction yield (Eq. (6) in Table 4) and their individual subgroups
– free TTAs (Eq. (4) in Table 4) and acetylated TTAs (Eq. (5) in
Table 4) – are illustrated in Fig. 5a–c, respectively, for the constant
temperature of 40 ◦ C.
Fig. 5. Response surfaces at 40 ◦ C showing the effects of pressure and ethanol content on the (a) total TTAs extraction yield, (b) individual contribution of acetylated TTAs,
and (c) individual contribution of free TTAs. Dots are experimental data, and surfaces are given by Eqs. (6), (5) and (4) (Table 4), respectively.
7. R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
111
Fig. 6. Response surface showing the effect of pressure and ethanol content on triterpenic acids concentration in the extracts for: (a) T= 40◦ C, and (b) T= 60◦ C. Dots are
experimental data, and surface is given by Eq. (7) (Table 4).
The overall TTAs extraction yield clearly depends not only on
the ethanol content (p < 0.001) and pressure (p < 0.001) but also
on their combined effect (p < 0.001), in a very parallel way to that
seen above for total extraction yield. It should be pointed out
that experiments without cosolvent addition moderately uptake
this family of compounds comparatively to the removal achieved
by Soxhlet extraction with dichloromethane. For instance, the
maximum and minimum values obtained without cosolvent are
2.00 [200 bar, 50 ◦ C] and 0.05 g/kg [100 bar, 60 ◦ C], while the introduction of ethanol raises them to 4.95 [200 bar, 40 ◦ C] and 0.34
[100 bar, 60 ◦ C], respectively; these values correspond to 30.9, 0.7,
76.9 and 5.2% of the TTAs yield registered by Soxhlet extraction.
With regard to the individual contributions of the free TTAs
(Fig. 5b) and acetyl derivatives (Fig. 5c) to the whole triterpenic
acids family at 40 ◦ C, considerable differences between their trends
can be perceived: while the extraction of acetylated molecules
increase with pressure and cosolvent content until reaching a
plateau near 200 bar and 5% EtOH, the free TTAs removal does not
stabilize within the range of conditions studied. Acetylated TTAs
are extracted in large extent with pure CO2 , attaining 65.6% of the
Soxhlet reference value at 200 bar and 40 ◦ C, because of their higher
nonpolar character and thus higher affinity to SC-CO2 . This behavior is confirmed by their contributions to the overall extraction of
TTAs: there are 78% of acetylated acids at 100 bar and 85% at 200 bar.
Consequently, without the aid of EtOH, the global TTAs extraction
remains reliant on the acetylated TTAs contribution, as the yield of
the free acids is too low to play a relevant role.
On the other hand, the increased polarity imparted by ethanol
favors molecular interactions between the supercritical solvent
and the more polar triterpenoids, increasing the removal of free
triterpenic acids (2.74 g/kg of bark for 200 bar, 40 ◦ C, 5% EtOH, corresponding to 62.8% of the Soxhlet extraction value) and thus the
overall TTAs extraction yield. This subgroup is the most abundant of
the TTAs existent in the bark and represents 67.7% of their respective Soxhlet content.
3.3. Triterpenic acids concentration in extracts
Fig. 6a and b plots the experimental TTAs concentration in the
extracts along with the regressed surfaces (Eq. (7) in Table 4) at 40
and 60 ◦ C, respectively.
Despite the lower correlation coefficients achieved (Table 4),
the fitted model reasonably describe the experimental results
and trends. The maximum concentration predicted by the model
rounds 50% (wt.) and it is achieved at 200 bar, 40 ◦ C, 5% EtOH
(Fig. 6a). This result is overestimated since the experimental concentration is 43.0% (wt.). On the other hand, the minimum at 40 ◦ C
totals 16% (wt.), being obtained at 100 bar without ethanol addition. The pressure range of 100 to 150 bar, and 0% EtOH correspond
to the poor extraction conditions in terms of purity: between 15
and 25% only.
The aforepresented results revealed to be possible to boost TTAs
extraction using the combination of both pressure and ethanol
addition, as they expose that the same conditions that favor the
increase of the total extraction yield also lead to an enhancement
of the TTA concentration in the extracts.
3.4. Reproducibility and validation tests
As formerly stated, some runs were carried out to test the
experimental reproducibility and assess the validation of regressed
models. In this respect, two replicates of runs 9 and 27 were
considered (runs 32–35), while runs 28–31 were used for validation purposes. The individual responses are compiled in Table 5,
¯
together with the calculated averages (y) and standard deviations
(SD) for the reproducibility set, and the average absolute relative
deviations (AARDs) for the validation set.
With regard to the reproducibility tests, the results show that,
in general, the standard deviations are within 2–8% of the averages, indicating that the sample-to-sample reproducibility is very
acceptable considering that natural raw materials are involved in
the experiments.
With regard to the models validation, it is possible to observe
that they provide reliable estimates of the measured data. Note that
the validation set is included in the experimental space but was
established for conditions not considered in the design of experiments (e.g., 140 bar, 170 bar, 2.5% EtOH). The AARDs found were
15.1, 11.7, 21.2, 11.5 and 11.8% for the global, free TTAs, acetylated
TTAs, total TTAs extraction yields and TTAs concentration in the
extracts, respectively. In the whole, the average deviation of 14.3%
found confirms the acceptable predictive capability of the regressed
equations, particularly if we take into account that they are strict
reduced models (Table 4) and because of the aforementioned
9. R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
nature of the biomass. In numerous works in the literature, authors
accomplish the calculations with full models, despite containing
non-significant terms, which obviously improve the fittings and
estimates.
4. Conclusions
In this work, the supercritical CO2 extraction of E. globulus deciduous bark was carried out at different temperatures
(40–60 ◦ C), pressures (100–200 bar), and cosolvent (EtOH) contents
(0.0–5.0 wt. %) in order to select the optimum conditions that,
within the ranges considered, maximize triterpenic acids recovery and their concentration in extracts. The optimized independent
variables were: 200 bar, 40 ◦ C and 5% EtOH. Under these conditions, the regressed models provided an extraction yield of 1.2%
(wt.), TTAs concentration of 50%, which corresponds to TTAs yield
of 5.1 g/kg of bark and a recovery of 79.2% in comparison to reference Soxhlet extraction. The behavior of the free and acetylated
TTAs extraction was significantly different. The acetyl derivatives
were extensively removed and tended to a plateau near 200 bar
and 5% EtOH, while the free acids extraction always increased in
the range of conditions studied. These results may be attributed to
the inferior polarity of acetylated TTAs, and thus higher affinity to
SC-CO2 , when compared to the unesterified triterpenoids.
Acknowledgments
We acknowledge the 7th Framework Programme FP7/2007–
2013 for funding project AFORE: Forest Biorefineries: Added-value
from chemicals and polymers by new integrated separation, fractionation and upgrading technologies (CP-IP 228589-2), the BIIPP
project (QREN 11551) for awarding a grant to R.M.A.D., and to
CICECO (Pest-C/CTM/LA0011/2011).
Appendix A. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at http://dx.doi.org/10.1016/j.supflu.
2012.12.005.
References
[1] S. Fernando, S. Adhikari, C. Chandrapal, N. Murali, Biorefineries: current status,
challenges, and future direction, Energy & Fuels 20 (2006) 1727–1737.
[2] J.E. Holladay, J.F., White, J.J., Bozell, D. Johnson. Top value-added chemicals from
biomass: vol II—results of screening for potential candidates from biorefinery
lignin, 2007. Available from: http://www.pnl.gov/main/publications/external/
technical reports/PNNL-16983.pdf
[3] G.I. Trabado, D. Wilstermann, Eucalyptus universalis, Global Cultivated Eucalypt Forest Map 200 (2008) 8, Available from: http://www.git-forestry.com/
[4] R.M.A. Domingues, G.D.A. Sousa, C.S.R. Freire, A.J.D. Silvestre, C.P. Neto,
Eucalyptus globulus biomass residues from pulping industry as a source of
high value triterpenic compounds, Industrial Crops and Products 31 (2010)
65–70.
[5] P. Fernandes, J.M.S. Cabral, Phytosterols: applications and recovery methods,
Bioresource Technology 98 (2007) 2335–2350.
[6] A. Hamunen. Process for the purification of -sitosterol isolated from the
unsaponifiables in crude soap from the sulphate cellulose process, 1983. US
Patent 4422974.
[7] S.P. Pietarinen, S.M. Willfor, M.O. Ahotupa, J.E. Hemming, B.R. Holmbom, Knotwood and bark extracts: strong antioxidants from waste materials, Journal of
Wood Science 52 (2006) 436–444.
[8] P.A. Krasutsky, Birch bark research and development, Natural Product Reports
23 (2006) 919–942.
[9] R.M.A. Domingues, D.J.S. Patinha, G.D.A. Sousa, J.J. Villaverde, C.M. Silva, C.S.R.
Freire, A.J.D. Silvestre, C.P. Neto, Eucalyptus biomass residues from agro-forest
and pulping industries as sources of high-value triterpenic compounds, Cellulose Chemistry and Technology 45 (2011) 475–481.
[10] R.M.A. Domingues, G.D.A. Sousa, C.M. Silva, C.S.R. Freire, A.J.D. Silvestre, C.P.
Neto, High value triterpenic compounds from the outer barks of several Eucalyptus species cultivated in Brazil and in Portugal, Industrial Crops and Products
33 (2011) 158–164.
113
[11] C.S.R. Freire, A.J.D. Silvestre, C.P. Neto, J.A.S. Cavaleiro, Lipophilic extractives
of the inner and outer barks of Eucalyptus globulus, Holzforschung 56 (2002)
372–379.
[12] S.A.O. Santos, J.J. Villaverde, C.M. Silva, C.P. Neto, A.J.D. Silvestre, Supercritical
fluid extraction of phenolic compounds from Eucalyptus globulus Labill bark,
Journal of Supercritical Fluids 71 (2012) 71–79.
[13] D.J.S. Patinha, R.M.A. Domingues, J.J. Villaverde, A.M.S. Silva, C.M. Silva, C.S.R.
Freire, C.P. Neto, A.J.D. Silvestre, Lipophilic extractives from the bark of
Eucalyptus grandis x globulus, a rich source of methyl morolate: selective extraction with supercritical CO2, Industrial Crops and Products 43 (2013) 340–
348.
[14] R.M.A. Domingues, E.L.G. Oliveira, C.S.R. Freire, R.M. Couto, P.C. Simoes, C.P.
Neto, A.J.D. Silvestre, C.M. Silva, Supercritical fluid extraction of Eucalyptus
globulus bark-A promising approach for triterpenoid production, International
Journal of Molecular Sciences 13 (2012) 7648–7662.
[15] M.M.R. de Melo, E.L.G. Oliveira, A.J.D. Silvestre, C.M. Silva, Supercritical fluid
extraction of triterpenic acids from Eucalyptus globulus bark, Journal of Supercritical Fluids 70 (2012) 137–145.
[16] R.M.A. Domingues, M.M.R. de Melo, C.P. Neto, A.J.D. Silvestre, C.M. Silva,
Measurement and modeling of supercritical fluid extraction curves of Eucalyptus globulus bark: influence of the operating conditions upon yields
and extract composition, The Journal of Supercritical Fluids 72 (2012)
176–185.
[17] M.N. Laszczyk, Pentacyclic triterpenes of the lupane, oleanane and ursane group
as tools in cancer therapy, Planta Medica 75 (2009) 1549–1560.
[18] P. Dzubak, M. Hajduch, D. Vydra, A. Hustova, M. Kvasnica, D. Biedermann,
L. Markova, M. Urban, J. Sarek, Pharmacological activities of natural triterpenoids and their therapeutic implications, Natural Product Reports 23 (2006)
394–411.
[19] N. Sultana, A. Ata, Oleanolic acid and related derivatives as medicinally important compounds, Journal of Enzyme Inhibition and Medicinal Chemistry 23
(2008) 739–756.
[20] P. Yogeeswari, D. Sriram, Betulinic acid and its derivatives: a review on their
biological properties, Current Medicinal Chemistry 12 (2005) 657–666.
[21] J. Li, W.J. Guo, Q.Y. Yang, Effects of ursolic acid and oleanolic acid on human
colon carcinoma cell line HCT15, World Journal of Gastroenterology 8 (2002)
493–495.
[22] F. Mengoni, M. Lichtner, L. Battinelli, M. Marzi, C.M. Mastroianni, V. Vullo,
G. Mazzanti, In vitro anti-HIV activity of oleanolic acid on infected human
mononuclear cells, Planta Medica 68 (2002) 111–114.
[23] S. Fontanay, M. Grare, J. Mayer, C. Finance, R.E. Duval, Ursolic, oleanolic
and betulinic acids: antibacterial spectra and selectivity indexes, Journal of
Ethnopharmacology 120 (2008) 272–276.
[24] G.B. Singh, S. Singh, S. Bani, B.D. Gupta, S.K. Banerjee, Anti-inflammatory activity
of oleanolic acid in rats and mice, Journal of Pharmacy and Pharmacology 44
(1992) 456–458.
[25] J.H. Clark, S.J. Tavener, Alternative solvents: shades of green, Organic Process
Research & Development 11 (2007) 149–155.
[26] F.E.I. Deswarte, J.H. Clark, J.J.E. Hardy, Extraction of high-value chemicals from
wheat straw by supercritical carbon dioxide, Abstracts of Papers of the American Chemical Society 230 (2005) U61–U62.
[27] C. Eckert, C. Liotta, A. Ragauskas, J. Hallett, C. Kitchens, E. Hill, L. Draucker, Tunable solvents for fine chemicals from the biorefinery, Green Chemistry 9 (2007)
545–548.
[28] V. Castola, B. Marongiu, A. Bighelli, C. Floris, A. Laï, J. Casanova, Extractives of
cork (Quercus suber L.): chemical composition of dichloromethane and supercritical CO2 extracts, Industrial Crops and Products 21 (2005) 65–69.
[29] A. Felföldi-Gáva, S. Szarka, B. Simándi, B. Blazics, B. Simon, A. Kéry, Supercritical
fluid extraction of Alnus glutinosa L. Gaertn, The Journal of Supercritical Fluids
61 (2012) 55–61.
[30] C.P. Passos, R.M. Silva, F.A. Da Silva, M.A. Coimbra, C.M. Silva, Enhancement
of the supercritical fluid extraction of grape seed oil by using enzymatically
pre-treated seed, The Journal of Supercritical Fluids 48 (2009) 225–229.
[31] C.P. Passos, R.M. Silva, F.A. Da Silva, M.A. Coimbra, C.M. Silva, Supercritical fluid
extraction of grape seed (Vitis vinifera L.) oil. Effect of the operating conditions
upon oil composition and antioxidant capacity, Chemical Engineering Journal
160 (2010) 634–640.
[32] J. Shi, C. Yi, S.J. Xue, Y. Jiang, Y. Ma, D. Li, Effects of modifiers on the profile
of lycopene extracted from tomato skins by supercritical CO2 , Journal of Food
Engineering 93 (2009) 431–436.
´
´
[33] B. Damjanovic, D. Skala, J. Baras, D. Petrovic-Djakov, Isolation of essential oil
and supercritical carbon dioxide extract of Juniperus communis L. fruits from
Montenegro, Flavour and Fragrance Journal 21 (2006) 875–880.
[34] H. Sovova, R.P. Stateva, Supercritical fluid extraction from vegetable materials,
Reviews in Chemical Engineering 27 (2011) 79–156.
[35] E. Reverchon, I. De Marco, Supercritical fluid extraction and fractionation of
natural matter, The Journal of Supercritical Fluids 38 (2006) 146–166.
[36] A.L. Magalha˜es, S.P. Cardoso, B.R. Figueiredo, F.A. Da Silva, C.M. Silva, Revisiting
the Liu–Silva–Macedo model for tracer diffusion coefficients of supercritical,
liquid, and gaseous systems, Industrial & Engineering Chemistry Research 49
(2010) 7697–7700.
[37] A.L. Magalhães, F.A. Da Silva, C.M. Silva, New models for tracer diffusion
coefficients of hard sphere and real systems: application to gases, liquids and
supercritical fluids, The Journal of Supercritical Fluids 55 (2011) 898–923.
[38] A.L. Magalhães, F.A. Da Silva, C.M. Silva, Tracer diffusion coefficients of polar
systems, Chemical Engineering Science 73 (2012) 151–168.
10. 114
R.M.A. Domingues et al. / J. of Supercritical Fluids 74 (2013) 105–114
[39] H. Liu, C.M. Silva, E.A. Macedo, New equations for tracer diffusion coefficients
of solutes in supercritical and liquid solvents based on the LennardJones fluid model, Industrial & Engineering Chemistry Research 36 (1997)
246–252.
[40] A.L. Magalha˜es, F.A. Da Silva, C.M. Silva. Free-volume model for the diffusion coefficients of solutes at infinite dilution in supercritical CO2 and liquid
H2 O, The Journal of Supercritical Fluids, http://dx.doi.org/10.1016/j.supflu.
2012.12.004, in press.
[41] E.L.G. Oliveira, A.J.D. Silvestre, C.M. Silva, Review of kinetic models for supercritical fluid extraction, Chemical Engineering Research and Design 89 (2011)
1104–1117.
[42] M.J.H. Akanda, M.Z.I. Sarker, S. Ferdosh, M.Y.A. Manap, N.N.N. Ab Rahman, M.O.
Ab Kadir, Applications of supercritical fluid extraction (SFE) of palm oil and oil
from natural sources, Molecules 17 (2012) 1764–1794.
[43] D.C. Montgomery, Design and Analysis of Experiments, fifth ed., Wiley, New
York, 2000.
[44] S.G. Özkal, M.E. Yener, L. Bayındırlı, Response surfaces of apricot kernel oil yield
in supercritical carbon dioxide, LWT – Food Science and Technology 38 (2005)
611–616.
[45] M.G. Bernardo-Gil, R. Roque, L.B. Roseiro, L.C. Duarte, F. Gírio, P. Esteves,
Supercritical extraction of carob kibbles (Ceratonia siliqua L.), The Journal of
Supercritical Fluids 59 (2011) 36–42.
[46] A.N. Assimopoulou, V.P. Papageorgiou, GC–MS analysis of penta- and tetracyclic triterpenes from resins of Pistacia species. Part II. Pistacia terebinthus var.
Chia, Biomedical Chromatography 19 (2005) 586–605.
[47] H. Budzikiewicz, J.M. Wilson, C. Djerassi, Mass spectrometry in structural and
stereochemical problems. 32 pentacyclic triterpenes, Journal of the American
Chemical Society 85 (1963) 3688–3699.