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
Application of response surface methodology for biosorption of reactive dyes ...IJLT EMAS
Response Surface Methodology was employed for
studying the biosorption of reactive dyes from textile effluent by
utilization of dead biomass of Rhizopus arrhizus in a batch
system. Central Composite Design at the specified combinations
of four variables (pH, biosorbent dosage, speed of agitation,
contact time) was adopted to achieve maximum biosorption. The
fitted quadratic model (P<0.0001) was used to arrive at the best
operating conditions. Under the following optimum conditions
i.e., pH 2.0; biosorbent dosage 3 g /L; speed of agitation 80 rpm
and contact time 60 min, 99.60% of the dyes were removed from
the wastewater. The mechanism of biosorption was elucidated by
FTIR, XRD and BET analysis. This work demonstrated the
feasibility of employing Rhizopus arrhizus as an effective and
economical fungal biosorbent for the removal of dyes from the
textile effluent.
Sequential anaerobic and aerobic treatment of pulp and paper mill efluenteSAT Journals
Abstract Paper mill is one of the major sources of pollution causing industry with intensely coloured effluent. The effluent is rich in lignocellulosic materials and other chemicals used during manufacturing which results in high Bio-chemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Due to its high toxic and mutagenic nature when discharged untreated there is a growing demand to treat the effluent before discharge. Biological treatment is a promising technique as it greatly reduces colour, BOD and COD. Various fungal and bacterial species are capable of degrading the lignocellulosic materials present in the effluent. In the present study characterization of the paper mill effluent and identification of the degradation efficiency of lignin degrading fungal species - Pleurotus species and Rhizopus stolonifer and bacterial species – Pseudomonas aeruginosa and Bacillus subtilis in laboratory scale was done. Here sequential anaerobic and aerobic treatment was carried out in two bio-reactors in series. The study indicated that anaerobic treatment gave a reduction of colour (18%), lignin (25%), COD (36%), BOD (28%) in 5days. The anaerobically treated effluent was then separately given to the aerobic reactors containing the fungal and bacterial species. Data obtained indicated that the Rhizopus showed good reduction in colour (71%), lignin (77%), COD (68%) and BOD (70%) in 5days whereas Pleurotus, Pseudomonas and Bacillus species showed reduction in colour (68%, 31%, 18%), lignin (64%, 43%, 44%), COD (58%, 42%, 43%) and BOD (60%, 40%, 42%) respectively in 5days. Thus Rhizopus was identified as the microbe with better degradation capacity. Key Words: Pulp and paper mill effluent1, Lignin, Anaerobic treatment, Rhizopus stolonifer.
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
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
Application of response surface methodology for biosorption of reactive dyes ...IJLT EMAS
Response Surface Methodology was employed for
studying the biosorption of reactive dyes from textile effluent by
utilization of dead biomass of Rhizopus arrhizus in a batch
system. Central Composite Design at the specified combinations
of four variables (pH, biosorbent dosage, speed of agitation,
contact time) was adopted to achieve maximum biosorption. The
fitted quadratic model (P<0.0001) was used to arrive at the best
operating conditions. Under the following optimum conditions
i.e., pH 2.0; biosorbent dosage 3 g /L; speed of agitation 80 rpm
and contact time 60 min, 99.60% of the dyes were removed from
the wastewater. The mechanism of biosorption was elucidated by
FTIR, XRD and BET analysis. This work demonstrated the
feasibility of employing Rhizopus arrhizus as an effective and
economical fungal biosorbent for the removal of dyes from the
textile effluent.
Sequential anaerobic and aerobic treatment of pulp and paper mill efluenteSAT Journals
Abstract Paper mill is one of the major sources of pollution causing industry with intensely coloured effluent. The effluent is rich in lignocellulosic materials and other chemicals used during manufacturing which results in high Bio-chemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Due to its high toxic and mutagenic nature when discharged untreated there is a growing demand to treat the effluent before discharge. Biological treatment is a promising technique as it greatly reduces colour, BOD and COD. Various fungal and bacterial species are capable of degrading the lignocellulosic materials present in the effluent. In the present study characterization of the paper mill effluent and identification of the degradation efficiency of lignin degrading fungal species - Pleurotus species and Rhizopus stolonifer and bacterial species – Pseudomonas aeruginosa and Bacillus subtilis in laboratory scale was done. Here sequential anaerobic and aerobic treatment was carried out in two bio-reactors in series. The study indicated that anaerobic treatment gave a reduction of colour (18%), lignin (25%), COD (36%), BOD (28%) in 5days. The anaerobically treated effluent was then separately given to the aerobic reactors containing the fungal and bacterial species. Data obtained indicated that the Rhizopus showed good reduction in colour (71%), lignin (77%), COD (68%) and BOD (70%) in 5days whereas Pleurotus, Pseudomonas and Bacillus species showed reduction in colour (68%, 31%, 18%), lignin (64%, 43%, 44%), COD (58%, 42%, 43%) and BOD (60%, 40%, 42%) respectively in 5days. Thus Rhizopus was identified as the microbe with better degradation capacity. Key Words: Pulp and paper mill effluent1, Lignin, Anaerobic treatment, Rhizopus stolonifer.
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
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
Potential of Neem Leaf Powder as Bio Adsorbents for Dye Colour Removalijtsrd
In this study, two types of eco friendly and low cost bio adsorbents, Neem leaf powder NLP and acid treated Neem leaf powder TNLP were prepared for the removal of dye color from Congo red solution. The physicochemical parameters of the prepared absorbents were measured. The structural features of these absorbents were analyzed by FTIR, XRD, and SEM. These experiments were conducted with different process parameters such as adsorbent dosage and agitating time using batch adsorption method. Firstly, the dosage amount of adsorbents was optimized for constant shaking for one hour and it was observed that the maximum percent adsorption was found at 91 of 0.4 g for NLP and 76 of 0.4 g for TNLP. The optimum dosage amount of adsorbents, 0.4 g was selected for further study. After optimizing the adsorbent dosage, the optimum agitating time was observed at 60 min with the percent removal of 91 for NLP and 76 for TNLP. From this research, it was observed that NLP and TNLP can be used as bio adsorbents to remove the color of the dye solution. Thet Thet Wai | Ei Mon Aung | Nyein Chan Kyaw "Potential of Neem Leaf Powder as Bio-Adsorbents for Dye Colour Removal" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27987.pdfPaper URL: https://www.ijtsrd.com/engineering/chemical-engineering/27987/potential-of-neem-leaf-powder-as-bio-adsorbents-for-dye-colour-removal/thet-thet-wai
Treatment of Effluent from Granite Cutting Plant by Using Natural Adsorbents ...IJERD Editor
Granite cutting plant is one such industry that releases polluting and turbid effluent. The residue from all these processes is discharged with water as an effluent. The effluent mainly contains many solids that harm the environment. Hence it requires treatment techniques before disposal. Several conventional methods are available for removal of contaminants like coagulation, adsorption, polyelectrolyte methods and biological methods. Most of them are cost prohibitive. The reduction of solids concentration in the effluent before disposal by using the techniques, coagulation followed by adsorption using natural adsorbents, like rice husk carbon and saw dust carbon, in contrast to the usage of activated carbon as it is costly. From a local Granite cutting plant near Anantapur, the effluent is collected and its physico-chemical characteristics are estimated and found to be pH(7.5), TS(4240mg/l), TSS(21560mg/l), TDS(12373mg/l).Effluent obtained is subjected to coagulation by potash alum followed by adsorption using saw dust carbon and rice husk carbon.
Removal of Methylene Blue from Aqueous Solutions by Nitrated biomass of Cicer...IOSR Journals
Investigation of removal of methylene blue by nitrated biomass of Cicer arientinum is conducted in batch conditions. The effect of different parameters such as contact time, sorbent dose, pH and temperature has been studied. Adsorption kinetic modeling data were found out. The kinetics of biosorption results shows that sorption process is well explained by pseudo–second order model with determination coefficients higher than 0.99 for sorbent under all experimental conditions. The value Kp is found to be 0.652 to 2.43 for initial and final concentrations. Thermodynamic parameter via KD, ΔG has also been calculated to determine the spontaneity of the process. The low value of activation energy indicates that sorption is an activated and physical process. The Weber and Morris intraparticle diffusion model show liquid-film, mass transfer is effective sorption mechanism. Thus nitrated biomass of Cicer areintinum is a low cost and easily available efficiently used as an excellent sorbent for the removal of MB+ from wastewater. It can be safely concluded that biomass of Cicer arientinum is much economical effectual, viable and can be an alternative to more costly adsorbents.
Azo dyes are one of the oldest industrially synthesized organic compounds characterized by presence of Azo bond (-N=N-) and are widely utilized as coloring agents in textile, leather, cosmetic, paint, plastic, paper, and food industries During textile processing, inefficiencies in dyeing result in large amounts of the dyestuff (varying from 2% loss when using basic dyes to a 50% loss when certain reactive dyes used) is being directly lost to the wastewater, which ultimately finds its way into the environment. The physico-chemical method of industrial effluent treatment does not remove the dyes effectively. Microbial degradation and decolorization of azo dyes has gained more attention recently because of eco-friendly and inexpensive nature. Microbes and there enzymes could decolorize the dyes by both aerobic and anaerobic metabolis. This review provides a general idea of decolorization and biodegradation of azo dyes with various microbes and highlights the application of for the treatment of azo dye-containing wastewaters.
Effect of temperature on biodegradation of textile dyeing effluent using pilo...Agriculture Journal IJOEAR
Abstract— This study deals with the effect of temperature on treatment of real textile dyeing effluent using pilot scale two-phase Upflow Anaerobic Sludge Blanket (UASB) reactor with sago effluent as co-substrate under recycle mode. The temperature of the reactor was varied viz. 35, 40, 45 and 50 0C. The feed of the reactor was 30% of methanogenic outlet recycled and 70% of 70/30 (sago/textile dyeing effluent) mixing ratio were given at the bottom of the reactor. The reactor was operated at 24 h of HRT. The performance of the bioreactor was evaluated by monitoring the removal of Chemical Oxygen Demand (COD), removal of color, Volatile Fatty Acid (VFA) and biogas production. The overall COD and color removal were achieved maximum of 98.4% and 99.3% respectively. Based on temperature, the biogas production (0.512 m3/d) was maximum at 450C. From the VFA and alkalinity ratio values obtained indicate that the reactors were operated under steady state. The results shows, that the sago and textile dyeing effluent have wide variation in their characteristics were treated on combination, whereas the recycle ratios maintain the stability of reactor. This new technology supports the effective utilization of sago effluent in destruction of dyeing effluent; the optimum temperature for efficient reactor operation was 450C.
It is generally accepted that a low level of fluorine in mains water 0.4 to 1 mg -¢ L – 1 depending on the climate of the country concerned promotes the formation of tooth enamel and protects teeth from decay. On the other hand, too much fluorine will destroy this enamel and cause a range of endemic type disorders that are generally called “fluoroses- malformed teeth, staining of the enamel, decalcification, tendon mineralisation, digestive and nervous disorders, etc. These problems can appear in individuals for widely variable quantities of the product. Water must be discharged or treated as soon as it contains more than 1 to 1.5 mg -¢ L – 1 of F – . Some natural waters contain more than 10 mg -¢ L – 1 of fluorine. This concentration has to be reduced to approximately 1 mg -¢ L – 1 the acceptable concentration falling as the average annual temperature rises the European standard has set 1.5 mg -¢ L – 1. Many studies have been carried out to address the issue however little success has been reported up to date. Layered double hydroxides LDHs which readily undergo anion exchange reactions have been used as a suitable candidate for defluorination. Also there is regeneration of the material after removal of fluoride ions without releasing flouride ions back in to the water cycle. F elimination using a nanofiltration NF operation will solve problems for large scale pilot plants in the future.Many defluorination projects have significant effectiveness on the prevention of endemic fluorosis. The concentrations of water fluoride were below 1 mg L. Advanced on site methods, such as under sink reserve osmosis units, can remove fluoride but are too expensive for developing areas. Calcium carbonate as a cost effective sorbent for an onsite defluorination drinking water system. Batch and column experiments have been performed to characterize F removal properties. The present review discusses various techniques of defluorination of water. Dr. Atul Kumar Sharma | Dr. Harsukh Ram Chharang "Defluorination of Drinking Water" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd46324.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/46324/defluorination-of-drinking-water/dr-atul-kumar-sharma
Statistical optimization of adsorption variables for biosorption of chromium ...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
The present study was an effort to obtain paint degrading bacterial isolate from wall scrapings. The study included that microorganisms such as bacteria, not only cause discoloration of paint surfaces but also, they can directly cause degradation of the materials through their metabolic activities. The Halophilic microorganisms are well known for their paint degrading activity. As evidenced from the literature survey, there is a great diversity of bacteria and fungi that are capable of growing on paint coating. The presence of various polymer compounds used in paint manufacturing makes it resistant to degradation and continue to be a potential hazard to the environment as well as humans. Use of nonabrasive and environmentally safe methods, to reduce the impact of microbial activities can further reduce the damage as well as help in bioremediation of paint contaminated water, soil and environments to clean up.
Adsorption Studies of an Acid Dye From Aqueous Solution Using Lagerstroemia ...IJMER
The effectiveness of adsorption for acid dye removal from wastewaters has made it an ideal alternative to other expensive treatment options. The removal of acid Violet 4BS onto seeds of Lagerstroemia indica (LIS) from aqueous solutions was investigated using parameters such as contact time, pH, temperature, adsorbent doses, and initial dye concentration. Adsorption isotherms of dyes onto LIS were determined and correlated with common isotherm equations such as the Langmuir and
Freundlich models. It was found that the Langmuir isotherm appears to fit the isotherm data better than
the Freundlich isotherm. Parameters of the Langmuir and Freundlich isotherms were determined using adsorption data. The maximum removal of Acid Violet 4BS by the adsorbent was obtained at pH 2. The maximum percentage of dye removal (86.67%) was obtained at an initial dye concentration of 10mg/L with adsorbent dosage of 50 mg per 50 ml of dye solution. The adsorption kinetics of acid violet 4BS could be described by the pseudo-second order reaction model. The data obtained from adsorption
isotherms at different temperatures were used to calculate several thermo-dynamic quantities such as the
Gibbs energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS
0) of adsorption. The adsorption process was found
to be spontaneous, exothermic and physical in nature. Locally available adsorbent LIS was found to have
a low cost and was promising for the removal of acid violet 4BS from aqueous solutions
The impact of flow rate and bed height on the adsorption behavior of methylene blue, Bismarck brown y, and indigo dyes on to Cedrus libani was investigated. The biomass was characterized by scanning electron microscopy as well as Fourier transformed infrared spectroscopy before and after adsorption to ascertain the functional groups responsible for the adsorption. The amount of dye adsorbed per unit mass of the biomass (qe) was calculated and was found to be dependent on the variables investigated within the experimental range. It was discovered that increase in bed height and flow rate increased the value of the dye adsorbed on to the biomass. The results obtained show that methylene blue dye adsorbed more onto the biomass, while indigo dye adsorbed at the least level.
Potential of Neem Leaf Powder as Bio Adsorbents for Dye Colour Removalijtsrd
In this study, two types of eco friendly and low cost bio adsorbents, Neem leaf powder NLP and acid treated Neem leaf powder TNLP were prepared for the removal of dye color from Congo red solution. The physicochemical parameters of the prepared absorbents were measured. The structural features of these absorbents were analyzed by FTIR, XRD, and SEM. These experiments were conducted with different process parameters such as adsorbent dosage and agitating time using batch adsorption method. Firstly, the dosage amount of adsorbents was optimized for constant shaking for one hour and it was observed that the maximum percent adsorption was found at 91 of 0.4 g for NLP and 76 of 0.4 g for TNLP. The optimum dosage amount of adsorbents, 0.4 g was selected for further study. After optimizing the adsorbent dosage, the optimum agitating time was observed at 60 min with the percent removal of 91 for NLP and 76 for TNLP. From this research, it was observed that NLP and TNLP can be used as bio adsorbents to remove the color of the dye solution. Thet Thet Wai | Ei Mon Aung | Nyein Chan Kyaw "Potential of Neem Leaf Powder as Bio-Adsorbents for Dye Colour Removal" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27987.pdfPaper URL: https://www.ijtsrd.com/engineering/chemical-engineering/27987/potential-of-neem-leaf-powder-as-bio-adsorbents-for-dye-colour-removal/thet-thet-wai
Treatment of Effluent from Granite Cutting Plant by Using Natural Adsorbents ...IJERD Editor
Granite cutting plant is one such industry that releases polluting and turbid effluent. The residue from all these processes is discharged with water as an effluent. The effluent mainly contains many solids that harm the environment. Hence it requires treatment techniques before disposal. Several conventional methods are available for removal of contaminants like coagulation, adsorption, polyelectrolyte methods and biological methods. Most of them are cost prohibitive. The reduction of solids concentration in the effluent before disposal by using the techniques, coagulation followed by adsorption using natural adsorbents, like rice husk carbon and saw dust carbon, in contrast to the usage of activated carbon as it is costly. From a local Granite cutting plant near Anantapur, the effluent is collected and its physico-chemical characteristics are estimated and found to be pH(7.5), TS(4240mg/l), TSS(21560mg/l), TDS(12373mg/l).Effluent obtained is subjected to coagulation by potash alum followed by adsorption using saw dust carbon and rice husk carbon.
Removal of Methylene Blue from Aqueous Solutions by Nitrated biomass of Cicer...IOSR Journals
Investigation of removal of methylene blue by nitrated biomass of Cicer arientinum is conducted in batch conditions. The effect of different parameters such as contact time, sorbent dose, pH and temperature has been studied. Adsorption kinetic modeling data were found out. The kinetics of biosorption results shows that sorption process is well explained by pseudo–second order model with determination coefficients higher than 0.99 for sorbent under all experimental conditions. The value Kp is found to be 0.652 to 2.43 for initial and final concentrations. Thermodynamic parameter via KD, ΔG has also been calculated to determine the spontaneity of the process. The low value of activation energy indicates that sorption is an activated and physical process. The Weber and Morris intraparticle diffusion model show liquid-film, mass transfer is effective sorption mechanism. Thus nitrated biomass of Cicer areintinum is a low cost and easily available efficiently used as an excellent sorbent for the removal of MB+ from wastewater. It can be safely concluded that biomass of Cicer arientinum is much economical effectual, viable and can be an alternative to more costly adsorbents.
Azo dyes are one of the oldest industrially synthesized organic compounds characterized by presence of Azo bond (-N=N-) and are widely utilized as coloring agents in textile, leather, cosmetic, paint, plastic, paper, and food industries During textile processing, inefficiencies in dyeing result in large amounts of the dyestuff (varying from 2% loss when using basic dyes to a 50% loss when certain reactive dyes used) is being directly lost to the wastewater, which ultimately finds its way into the environment. The physico-chemical method of industrial effluent treatment does not remove the dyes effectively. Microbial degradation and decolorization of azo dyes has gained more attention recently because of eco-friendly and inexpensive nature. Microbes and there enzymes could decolorize the dyes by both aerobic and anaerobic metabolis. This review provides a general idea of decolorization and biodegradation of azo dyes with various microbes and highlights the application of for the treatment of azo dye-containing wastewaters.
Effect of temperature on biodegradation of textile dyeing effluent using pilo...Agriculture Journal IJOEAR
Abstract— This study deals with the effect of temperature on treatment of real textile dyeing effluent using pilot scale two-phase Upflow Anaerobic Sludge Blanket (UASB) reactor with sago effluent as co-substrate under recycle mode. The temperature of the reactor was varied viz. 35, 40, 45 and 50 0C. The feed of the reactor was 30% of methanogenic outlet recycled and 70% of 70/30 (sago/textile dyeing effluent) mixing ratio were given at the bottom of the reactor. The reactor was operated at 24 h of HRT. The performance of the bioreactor was evaluated by monitoring the removal of Chemical Oxygen Demand (COD), removal of color, Volatile Fatty Acid (VFA) and biogas production. The overall COD and color removal were achieved maximum of 98.4% and 99.3% respectively. Based on temperature, the biogas production (0.512 m3/d) was maximum at 450C. From the VFA and alkalinity ratio values obtained indicate that the reactors were operated under steady state. The results shows, that the sago and textile dyeing effluent have wide variation in their characteristics were treated on combination, whereas the recycle ratios maintain the stability of reactor. This new technology supports the effective utilization of sago effluent in destruction of dyeing effluent; the optimum temperature for efficient reactor operation was 450C.
It is generally accepted that a low level of fluorine in mains water 0.4 to 1 mg -¢ L – 1 depending on the climate of the country concerned promotes the formation of tooth enamel and protects teeth from decay. On the other hand, too much fluorine will destroy this enamel and cause a range of endemic type disorders that are generally called “fluoroses- malformed teeth, staining of the enamel, decalcification, tendon mineralisation, digestive and nervous disorders, etc. These problems can appear in individuals for widely variable quantities of the product. Water must be discharged or treated as soon as it contains more than 1 to 1.5 mg -¢ L – 1 of F – . Some natural waters contain more than 10 mg -¢ L – 1 of fluorine. This concentration has to be reduced to approximately 1 mg -¢ L – 1 the acceptable concentration falling as the average annual temperature rises the European standard has set 1.5 mg -¢ L – 1. Many studies have been carried out to address the issue however little success has been reported up to date. Layered double hydroxides LDHs which readily undergo anion exchange reactions have been used as a suitable candidate for defluorination. Also there is regeneration of the material after removal of fluoride ions without releasing flouride ions back in to the water cycle. F elimination using a nanofiltration NF operation will solve problems for large scale pilot plants in the future.Many defluorination projects have significant effectiveness on the prevention of endemic fluorosis. The concentrations of water fluoride were below 1 mg L. Advanced on site methods, such as under sink reserve osmosis units, can remove fluoride but are too expensive for developing areas. Calcium carbonate as a cost effective sorbent for an onsite defluorination drinking water system. Batch and column experiments have been performed to characterize F removal properties. The present review discusses various techniques of defluorination of water. Dr. Atul Kumar Sharma | Dr. Harsukh Ram Chharang "Defluorination of Drinking Water" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd46324.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/46324/defluorination-of-drinking-water/dr-atul-kumar-sharma
Statistical optimization of adsorption variables for biosorption of chromium ...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
The present study was an effort to obtain paint degrading bacterial isolate from wall scrapings. The study included that microorganisms such as bacteria, not only cause discoloration of paint surfaces but also, they can directly cause degradation of the materials through their metabolic activities. The Halophilic microorganisms are well known for their paint degrading activity. As evidenced from the literature survey, there is a great diversity of bacteria and fungi that are capable of growing on paint coating. The presence of various polymer compounds used in paint manufacturing makes it resistant to degradation and continue to be a potential hazard to the environment as well as humans. Use of nonabrasive and environmentally safe methods, to reduce the impact of microbial activities can further reduce the damage as well as help in bioremediation of paint contaminated water, soil and environments to clean up.
Adsorption Studies of an Acid Dye From Aqueous Solution Using Lagerstroemia ...IJMER
The effectiveness of adsorption for acid dye removal from wastewaters has made it an ideal alternative to other expensive treatment options. The removal of acid Violet 4BS onto seeds of Lagerstroemia indica (LIS) from aqueous solutions was investigated using parameters such as contact time, pH, temperature, adsorbent doses, and initial dye concentration. Adsorption isotherms of dyes onto LIS were determined and correlated with common isotherm equations such as the Langmuir and
Freundlich models. It was found that the Langmuir isotherm appears to fit the isotherm data better than
the Freundlich isotherm. Parameters of the Langmuir and Freundlich isotherms were determined using adsorption data. The maximum removal of Acid Violet 4BS by the adsorbent was obtained at pH 2. The maximum percentage of dye removal (86.67%) was obtained at an initial dye concentration of 10mg/L with adsorbent dosage of 50 mg per 50 ml of dye solution. The adsorption kinetics of acid violet 4BS could be described by the pseudo-second order reaction model. The data obtained from adsorption
isotherms at different temperatures were used to calculate several thermo-dynamic quantities such as the
Gibbs energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS
0) of adsorption. The adsorption process was found
to be spontaneous, exothermic and physical in nature. Locally available adsorbent LIS was found to have
a low cost and was promising for the removal of acid violet 4BS from aqueous solutions
The impact of flow rate and bed height on the adsorption behavior of methylene blue, Bismarck brown y, and indigo dyes on to Cedrus libani was investigated. The biomass was characterized by scanning electron microscopy as well as Fourier transformed infrared spectroscopy before and after adsorption to ascertain the functional groups responsible for the adsorption. The amount of dye adsorbed per unit mass of the biomass (qe) was calculated and was found to be dependent on the variables investigated within the experimental range. It was discovered that increase in bed height and flow rate increased the value of the dye adsorbed on to the biomass. The results obtained show that methylene blue dye adsorbed more onto the biomass, while indigo dye adsorbed at the least level.
The adsorption behavior of Methylene blue dye, Bismarck brown Y dye, and Indigo dye on to Sphagnum cymbifolium (moss) was investigated as a function of flow rate, and bed height through the fixed bed process.
One of the main objectives of this research is to expand the field of application of natural biomass for the treatment of dye waste waters from industrial effluents. Additionally, it is aimed at elucidating the dependency or otherwise of flow rate, and bed height on adsorption using the fixed bed technique method of adsorption.
The biomass was characterized by Scanning Electron Microscopy in order to examine the morphology of the biomass. The screened biomass samples were characterized at 1000 ×magnification, and 500 ×magnification respectively for their surface morphologies. This was done using a scanning electron microscope which was equipped with an energy dispersive x-ray spectrophotometer employed for the elemental composition analyses. It was equally characterized with Fourier Transformed Infrared Spectroscopy before and after adsorption to ascertain the functional groups responsible for the adsorption. This was done using a Fourier Transformed Infrared Spectrophotometer (Perkin-Elmer, England) in the wavelength range of 350-4000 nm.
Results for the biomass morphology obtained through the Scanning Electron Microscopy revealed the presence of tiny pores. These pores represent sites where dye molecules could be trapped in the course of the adsorption. The result from the Fourier Transformed Infrared Spectroscopy after adsorption show that C-H, C≡H, C≡C functional groups were responsible for the adsorption. For methylene blue dye, at the flow rate of 20 m3/s, the amount of dye adsorbed was 18.80 mg/g, 22.70 mg/g at 30 m3/s, and 25.40 mg/g at 40 m3/s. For Bismarck brown Y dye, at the same range of flow rate, the amount of dye adsorbed ranged from 12.34 mg/g - 20.62 mg/g. For indigo dye, the values obtained ranged from 6.48 mg/g - 17.71 mg/g. In addition, at the bed height range of 4.0 - 6.0x10-2(m), the amount of dye adsorbed ranged from 6.31 mg/g - 27.73 mg/g for methylene blue dye. Within the same range of bed height, the amount of dye adsorbed ranged from 16.40 mg/g - 25.60 mg/g for Bismarck brown y dye, and 12.57 mg/g - 17.71 mg for indigo dye.
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Abstract
The removal of colour from silk filature composite wastewater by adsorption on activated carbon prepared from MangiferaIndica
(mango) seed shell have been carried out at room temperature 32 ± 1° C. The removal of colour from silk filature composite
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optimum time, optimum dosages and variation of pH was studied. It is observed that as dosage increases the adsorption increased
along with the increase in Impregnation ratio. It was also noted that as I.R. increases the surface area of MangiferaIndica shell
carbon increased. Hence the maximum removal efficiency is obtained at I.R ratio of 0.75. The optimum contact time, dosage and pH
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Adsorption studies of colourremoval byactivated carbon derived from mangifera...eSAT Journals
Abstract
The removal of colour from silk filature composite wastewater by adsorption on activated carbon prepared from MangiferaIndica
(mango) seed shell have been carried out at room temperature 32 ± 1° C. The removal of colour from silk filature composite
wastewater sample by adsorption on chemical activation (Magnesium chloride) with Impregnation ratio’s (I.R) 0.25, 0.50, 0.75 for
optimum time, optimum dosages and variation of pH was studied. It is observed that as dosage increases the adsorption increased
along with the increase in Impregnation ratio. It was also noted that as I.R. increases the surface area of MangiferaIndica shell
carbon increased. Hence the maximum removal efficiency is obtained at I.R ratio of 0.75. The optimum contact time, dosage and pH
for carbon with I.R-0.75 was 45min, 100mg and 5.5 with removal efficiency of 81.11%, 96.66% and 96.66% respectively.
Keywords: Colour, Contact time, Dosage, Kinetics, pH, MangiferaIndica.
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F041014356
1. IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org
ISSN (e): 2250-3021, ISSN (p): 2278-8719
Vol. 04, Issue 10 (October. 2014), ||V1|| PP 43-56
International organization of Scientific Research 43 | P a g e
Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells *G. Zuhra Memona, M. Moghala, Jamil R. Memona , Nusrat N. Memona, M. I. Bhangerb Dr. M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, Pakistan bNational Center of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Pakistan Abstract:- In the present studies efforts are made to develop a low cost method to remove pesticides from water streams. Low cost walnut shells after chemical and thermal treatment are used to remove carbofuran and Chloropyriphos pesticides from aqueous solutions. The adsorption parameters i.e. pH, contact time, shaking speed and initial concentration have been studied. The adsorption was found to be rapid 97-99% within 30 min. The adsorption of pesticides on the adsorbent surface was found to be pH dependent. The adsorbent material was characterized by scanning electron microscopy (SEM) analysis and FT-IR spectroscopy. Elution experiments were performed to recover the adsorbed pesticide from the adsorbent surface. The Freundlich, Langmuir, D-R and Thomas models were used to study the partitioning behavior for the adsorption system along with kinetic and thermodynamic studies. The proposed adsorption method was utilized to remove carbofuran and Chloropyriphos pesticides from environmental water samples. Key word: Adsorption; pesticides; Walnut shell; Isotherms, Kinetics; thermodynamics.
I. INTRODUCTION
Pesticides are being ever more used to control the loss of agricultural crops and improve yield. In developing countries like Pakistan, the use of pesticides is dispossessed to be so imperative that they are associated with growth of human benefit [1]. Extensive usage of pesticides is accountable for water contamination because of their leaching and runoff losses. Inappropriate discarding of the empty pesticide bottles, washing of spray instruments and unfettered discharge from manufacturing units are further sources of water resources contamination. In the past few years the existence of pesticide residues in ground water resources has experienced extensively and has turn out to be an intensive and burning issue of discussion [2]. Carbofuran (2,3-dihydro- 2,2-dimethyl-7-benzofuranyl-N-methylcarbamate) is a broad spectrum carbamates pesticide, used to control insects in a wide range of crops i.e. potatoes, corn and soybeans. WHO classified carbofuran as highly hazardous pesticide [3]. Carbofuran is highly toxic by inhalation and ingestion and moderately toxic by dermal absorption causes asthma, diabetes, cardiovascular disease etc [5]. Like wise Chloropyriphos (O,O diethyl O (3,5,6 Trichloro-2-pyridyl) an organophosphorous pesticide used against soil insects of field and vegetable crops. Chloropyriphos is more persistent than most organophosphates, possibly because it is stored in fatty tissues and released over time. Chloropyriphos when ingested by animals is converted to chloropyriphos-oxon which is more toxic than chloropyriphos itself. Several methods are used to control contamination of water by organic pollutants i.e. biotreatment, air stripping, chemical oxidation, and adsorption by granular activated carbon [6]. However, nowadays adsorption by granular activated carbon is a broad spectrum technology. Yet owing the high cost of activated carbon, its use is restricted on economical contemplation. Alternatively low-cost adsorbents from agricultural by-products i.e. chestnut shells, watermelon peels, mango kernel, banana peel, orange peel, chickpea husk, hazelnut shell etc [7-13] have been investigated as a potential alternative to activated carbon. In the present work efforts have been made to develop low cost methods for water purification. The indigenously produced activated adsorbent from walnut shell is employed as low-cost adsorbent for the removal of pesticides from contaminated water streams.
II. MATERIAL AND METHODS
All chemicals and reagents used were of analytical grade and procured from Fluka /Merck (Germany). Pesticides were obtained from Sigma Aldrich Co. (Seelze, 22 Germany). Methanol (HPLC grade) was procured from Fisher Scientific (UK) and used for making synthetic aqueous solutions and for HPLC.
III. INSTRUMENTATION
Hitachi model 6200 HPLC equipped with a Licrosorb octadecylsilane (ODS) Inertsil column 5μm
2. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 44 | P a g e
(250×4 Ø mm) is used for analysis of pesticides. Water-methanol mixture (30:70) v/v was used as a mobile
phase at a flow rate of 1 ml min-1. The limit of detection (signal to noise ratio 2:1) was found to be 0.03 ng μl-1
and 0.07 ng μl-1 at selected wave lengths of 275 nm and 214 nm for carbofuran and chloropyriphos respectively.
Perkins Elmer UV/Vis spectrometer Lambda 2 is used for the determination of maximum wavelengths of
carbofuran and chloropyriphos. The pH measurements are made on digital (InoLab pH level I) pH meter. The
Gallenkamp automatic shaker model BKS 305-010 UK is used for the batch experiments. The surface area
measurement was carried out by BET (Brunauer, Emmett and Teller) method using nitrogen as a standard by
employing surface area analyzer (Quantasorb, QS-7) [15].
The IR spectra was acquired using a Thermo Nicolet Avatar 330 FTIR spectrometer equipped with a deuterated
triglycine sulfate (DTGS) detector and KBr optics and controlled by OMNIC software (Thermo Nicolet
Analytical Instruments, Madison, WI).
IV. ACTIVATION OF ADSORBENTS
The adsorption efficiency of adsorbets is depends upon the process of activation [16, 17]. To enhance the
surface area and porosity the adsorbent was activated by chemical as well as thermal activation.
1.1. Chemical and Thermal Activation of walnut shells
The Walnut shells were washed carefully with deionized water to remove impurities and then dried.
The sieved material (100 μm) was treated with 0.1 M nitric acid solution for 1 h to increase surface area of the
adsorbents [18]. The material was washed with deionized then soaked in methanol for 4 h to remove organic
matter from the surface followed by thermal activation in a closed muffle furnace (Phoenix, Sheffield, England,
1983) at 573 K for 1 h then kept in vacuum desiccators.
1.1.1. Surface Characterization of Adsorbents
The strength of adsorption possibly be affected by the physicochemical characteristics of the adsorbent such as
surface area, pore size, surface functional groups, and composition [19]. Different activation treatments verify
clearly different adsorption characteristics [20]. Consequently, an effective adsorbent should have a large
surface area with the appropriate pore size to adsorb the targeted species.
4.2.1. BET (Brunauer, Emmett and Teller) Method
The surface area measurement was carried out by BET (Brunauer, Emmett and Teller) method. After chemical
and thermal treatment surface area of the adsorbents was increased [12]. The specific surface area of unactivated
walnut shells was found 32.4 ± 1.2 m2/g, while, after activation it was increased as 83.3 ± 2.4 m2/g.
4.2.2. FT-IR Spectroscopy
The FT-IR spectra of activated and unactivated walnut shells were recorded for determining the nature
of surface groups responsible for binding of pesticides. The presence of a large number of peaks at different
positions in FT-IR spectra Fig. 1, indicating the complex chemical nature of the material.
1032.3
1241.4
1313.1
1596.41 374.3
1731.5
2853.6
2921.2
3288.3
83
84
85
86
87
88
89
90
91
92
93
94
95
96
%T
4000 3500 3000 2500 2000 1500 1000 500
Wave numbers (cm-1)
Walnut shells
Walnut shells activated
activated
activated
Fig. 1 FT-IR spectra of walnut shell
The results obtained by FT-IR analysis confirms the presence of functional groups such as alcoholic,
3. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 45 | P a g e
carboxylic, carbonyl and ether groups in the structure of the biomass surface and carbonaceous material [21]. which may play a significant part to bind the pesticides on the surface of walnut shell at low pH. 4.2.3. Scanning Electron Microscopy and Energy Dispersive X-ray analysis The surface area morphologies of adsorbents were studied with A Hitachi S2300 Scanning Electron Microscope (SEM) at 25 kV accelerating voltage. SEM images reveals that the porosity of walnut shell was increased after chemical and thermal activation as shown in Fig. 2 a & b. Fig. 2 (a) SEM image of untreated walnut shell Fig. 2 (b) SEM image of chemically and thermally treated walnut shell 4.3. Adsorption Method 4.3.1. Batch Adsorption Method An optimum amount of walnut shell was taken in a flasks containing pesticide solution and fitted to a thermostatic shaker at constant pH. The sample was filtered and was then injected to HPLC under optimized conditions. 3.1.2 Column Adsorption Method
Adsorbent material (5 g) was puted into a glass column (6 mm × 150 mm), by adjusting the pH of the pesticide solution with an optimum concentration, the solution was passed through the column at flow rates
4. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 46 | P a g e
between 1-5 ml min-1. Consequently the column was washed with distilled water followed by methanol to
recover the adsorbed pesticides.
4.4. Data Manipulation
The % adsorption of pesticides was calculated using following equation:
% 100
i
i e
C
C C
Adsorption (1)
where Ci (mol dm−3) and Ce (mol dm−3) are the initial and equilibrium concentrations of pesticide in aqueous
solution, respectively.
5. Results and Discussions
5.1. Optimization of adsorption parameters
5.1.1 Effect of pH
Initially the experiments were carried out to select the most appropriate adsorptive medium to give
maximum adsorption. The buffers of pH 1-10 at an interval of one unit were investigated to observe the effect of
pH onto 0.1 g of adsorbent using 20 ml of 10 ppm solution of carbofuran and chloropyriphos separately with
100 rpm agitation speed for 60 min at 303 K. The percent adsorption was found to decrease with increasing pH
as portrayed in Fig 3.At very low pH values, the surface of the walnut shell would be surrounded by the
hydronium ions, which may enhance the pesticide interaction with binding sites of walnut shell to improve its
attachment on polar adsorbent [22-23].
Fig. 3 Effect of pH for the adsorption of carbofuran and chloropyriphos
5.1.2 Effect of Adsorbent Dosage
The effect of amount of adsorbent in the range of 0.01-1 g on removal of pesticide was studied at optimum
conditions As the mount of adsorbent increased, percentage adsorption was also increased to a limited value at
which saturation take place.
5.1.3 Effect of contact time
The time study was carried out in the range of 5-60 min, and it was observed that with the increase of time
pesticides uptake was also increased until certain limit (30 min) at which equilibrium was established. For
further studies 30 min of contact time was applied.
5.1.4 Effect of initial concentration of carbofuran
The effect of concentration of the carbofuran and chloropyriphos was studied in the range of 10-100 ppm using
0.1 g of adsorbent. %adsorption of pesticide was increased with increasing concentration until the equilibrium is
established at the solid–solution interface [24]. At the saturation point of adsorption on solid surface
%adsorption decreases with the increase of initial concentration.
0
20
40
60
80
100
0 2 4 6 8 10 12
pH
%Adsorption
CP CF
5. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 47 | P a g e
5.2 Adsorption isotherms
Langmuir, Freundlich and D-R isotherms were used to predict the equilibrium behavior of carbofuran and
chloropyriphos adsorption onto walnut shells.
The Freundlich adsorption equation is the most widely used mathematical description of adsorption on
aqueous systems. The linearized form of Freundlich isotherm is [25]
ads e C
n
C K log
1
log log
(2)
where 1/n is a characteristic constant related to sorption intensity, Cads is the sorbed concentration of adsorbate
onto adsorbent (mol g−1), and K is the multilayer sorption capacity of adsorbent (mol g−1).The Freundlich
isotherm was plotted between the log Cads
and log Ce which is linear in case of all three adsorbents as shown in
Fig. 4.
Fig.4 Freundlich adsorption isotherm of carbofuran and chloropyriphos
The Freundlich constant computed using slope of linear plots, 1/n <1 shows that adsorption is favorable at lower
equilibrium concentrations [26]. The values of Freundlich constants are given in Table 1.
The Langmuir adsorption isotherm describes quantitatively the build up of a layer of molecules on an
adsorbent surface as a function of the concentration of the adsorbed material in the liquid in which it is in
contact [27]. Langmuir presented a general equation for the isotherm of localized adsorption,
Q
C
C Qb
C e
ads
e
1
(3)
where Q is the monolayer adsorption saturation capacity (mol g−1), and b represents the enthalpy of sorption
(dm3 mol−1), independent of temperature. The plot of Ce/Cads against Ce presents a straight line as depicted in
Fig. 5.
-5
-4
-3
-2
-8 -6 -4 -2
log Ce (mol dm-3)
log Cads (mol g-1)
CP CF
6. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 48 | P a g e
Fig. 5 Langmuir adsorption isotherm of carbofuran and chloropyriphos
RL is an essential characteristic of Langmuir isotherm, it is the measure of the adsorbent capacity used given by
the equation:
i 1 bC
1
L R (4)
Table 1. Adsortion parameters for the adsorption of carbofuran and chlorophyriphos
The values of RL are in the range of 0.1-0.99 means 0< RL> 1 representing extremely favorable adsorption
process [28]. The values of adsorption capacity and intensity of adsorption calculated from the slope and
intercept of linear plots are also presented in Table 1.
A comparison of adsorption parameters of carbofuran pesticide, evaluated in present studies, with previously
reported parameters is given in Table 2.
Freundlich
constants
1/n
K (mmolg-1)
Regression coefficient (R2)
0.38 ± 0.008
22.9 ± 2.30
0.995 ± 0.015
0.34 ± 0.009
11.24 ± 1.16
0.993 ± 0.033
Langmuir
constants
Q (mmolg-1)
b (L mol-1)
Regression coefficient (R2)
RL (dimensionless factor)
0.89 ± 0.033
(5.0 ± 0.65 ) ×104
0.988 ± 0.01
(0.043-0.47)
0.987 ± 0.016
(1.23 ±) ×104
0.995 ± 0.008
0.026-0.35
D-R constants
Xm (mmolg-1)
E (kJ/mol)
Regression coefficient (R2)
(2.7 ± 0.06) ×10−4
13.9 ± 0.02
0.994 ± 0.007
1.53 ± 0.003
14.7 ± 0.019
0.995 ± 0.062
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.00005 0.0001 0.00015 0.0002
Ce (mol dm-3)
Ce/Cads (mol g-1)
CP CF
7. Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells
International organization of Scientific Research 49 | P a g e
Table 2 Comparison of carbofuran pesticide adsorption with previous studies
Adsorbent Adsorption capacities
mg/g
References
Walnut shell
K = 508, R2 = 0.995
Q = 0.19, R2 = 0.976
This studies
GAC
K = 23.5, R2 = 0.963
Q = 181.8, R2 = 0.992
[29]
Fertilizer and steel industry waste Q = 303, R2 = 0.992 [30]
Banana stalks
K = 29.4, R2 = 0.817
Q = 161.3, R2 = 0.989
[31]
No work is previously reported on chloropyriphos pesticide. On the basis of adsorption capacity and regression
coefficient values it is concluded that the adsorption data is best fitted to Freundlich adsorption isotherm
The D-R equation is an adaptation of the earlier Polanyi potential theory of adsorption [32,33]. The linear form
of D-R isotherm is given here:
ln ln ß ads m C X (5)
where Xm represents the maximum adsorption capacity of adsorbent (mol g−1), β is a constant related to
adsorption energy, while ε is Polanyi adsorption potential which can be evaluated by:
)
1
ln(1
e C
RT (6)
The D-R adsorption isotherm was studied by plotting ln Cads
versus Polanyi potential) as shown in Fig. 6.
The value of adsorption energy, E is calculated by.
2
1
E (7)
D-R constants are also given in Table 1.
Fig. 6 D-R adsorption isotherm of carbofuran and chloropyriphos
-11
-10
-9
-8
-7
-6
0 500 1000 1500 2000
є2
ln Cads (mol g-1)
CP CF
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5.3. Kinetics of adsorption
The Lagergren first order rate expression [34], is one of the most widely applied kinetic model to the adsorption
processes. The specific rate constant k for any adsorbate-adsorbent system in equilibrium can be calculated
from the first order rate equation, by plotting log (qe-qt) vs. time, t, as illustrated in Fig. 7. The adsorption of
carbofuran as well as chloropyriphos follow first order rate and the findings are given in Table 3.
Fig. 7 Lagergren plots of carbofuran and chloropyriphos
Table 3 Kinetic parameters for the adsorption of carbofuran and chloropyriphos onto walnut shell
Kinetic Parameters Carbofuran Chloropyriphos
k (min-1) 0.14 ± 0.005 0.039 ± 0.003
Regression coefficient R2 0.96 ± 0.004 0.973 ± 0.012
Rd (μmol g-1 min-1) 0.13 ± 0.03 82.17 ± 5.20
Regression coefficient (R2) 0.93 ± 0.001 0.958 ± 0.022
To investigate the nature of adsorption mechanism by film diffusion or intraparticle diffusion mechanism,
Reichenberg equation was used.
B 0.4977 ln(1 Q) t (8)
If intraparticle diffusion occurs, the curve will be linear and if the plot passes through the origin, then the rate
limiting process is only due to the intraparticle diffusion [35]. The plot of Bt versus time as shown in Fig. 8 is
not pasings through origin suggests the adsorption process is film diffusion process.
Fig. 8 Reichenberg plots of carbofuran and chloropyriphos
-20
-16
-12
-8
-4
0
0 10 20 30 40 50
Time (min)
ln (qe-qt)
CP CF
0
1
2
3
4
5
6
7
0 10 20 30 40 50 60
Time (min)
βt
CP CF
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5.4 Thermodynamics of adsorption
The thermodynamic parameters i.e. ΔH, ΔG and ΔS were evaluated using following equations [36]:
R
ΔS
RT
ΔH
ln Kc (9)
c G RT ln K
(10)
From the slope and intercept of plots of log Kc versus 1/T as shown in Fig. 9 ΔH and ΔS were calculated and the
findings are listed in Table 4.
Fig. 9 Effect of temperature for adsorption of carbofuran and chloropyriphos
The positive value of ΔH in case of chloropyriphos shows that adsorption process is endothermic whereas
negative ΔH value for carbofuran reveals the exothermic nature of adsorption process, while negative values of
ΔG suggests the spontaneous nature of adsorption.
Table 4 Thermodynamic parameters for the adssorption of carbofuran and chloropyriphos onto walnut shell
Thermodynamic Parameters Carbofuran Chloropyriphos
H (kJmol-1)
-38.05 ± 1.19 27.0 ± 1.09
S (kJmol-1 K-1)
-0.10 ± 0.003 0.11 ± 0.003
G303 K (kJmol-1)
-10.81 -6.15 ± 0.24
Regression coefficient (R2) 0.99 ± 0.006 0.992 ± 0.055
5.5 Column Adsorption Studies
Column adsorption studies were performed in order to estimate the practical applicability of adsorbent i.e.
walnut shells for the removal of carbofuran pesticide.
5.5.1 Effect of flow rate
The effect of flow rate on adsorption of carbofuran was examined at flow rate 1-6 ml min-1. %adsorption was
found maximum at flow rate of 2 ml min-1.
0
0.5
1
1.5
2
2.5
0.0025 0.0029 0.0033 0.0037
1/T (K-1)
log Kc
CP CF
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5.5.2 Break through curves
In adsorption studies the break through is portrayed when the effluent concentration of species from the
column is about 3-5% of the influent concentration. A solution containing 10 ppm of pesticides were passed
through the column. The plot of concentration of pesticide vs aliquot volumes creates the breakthrough curve.
The break through occurs at 5 dm3 as shown in Fig 10. The breakthrough volume determines the maximum
value of water sample containing pesticides introduced into the adsorbent. The sharp line of the curve Fig. 10
illustrates the favorable equilibrium [37].
Fig. 10 Break through curve for the adsorption of carbofuran and chloropyriphos
The maximum adsorption capacity of adsorbent is calculated using Thomas model on the basis of column
method.
Thomas Model
The Thomas model estimates the maximum solid phase concentration of adsorbate on the adsorbent surface and
the rate constant of adsorption for column method [38]. The linearized form of this model is:
Q
q m
C TH TH
C ac s
t
ads
k C t k 0 max
0 ln( 1)
(11)
The kinetic coefficient kTH and the adsorption capacity of the bed qt
acmx were calculated by plotting ln
(C0/Cads−1) vs. time as shown in Fig. 11. The results are given in Table 5.
Fig. 11 Thomas model of carbofuran and chloropyriphos
-6
-4
-2
0
2
4
6
0 100 200 300 400
Time (min)
ln(C0/Cads-1)
CF CP
0
2
4
6
8
10
0 2 4 6 8 10 12
Volume (dm3)
Concentration (ppm)
CP CF
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Table 5 Thomas model parameters for the adsorption of carbofuran onto steam treated walnut shells
Analyte
Q (ml/min)
C0 (mg/l)
kTH (ml/(min mg))
qacmax (mg/g)
R2
Carbofuran
2
10
0.57
4.43
0.948
Chloropyriphos
2.5
10
0.46
4.26
0.957
5.6 Recovery of Carbofuran Different solvents were used to desorb the adsorbed pesticides from the surface of walnut shells. It was found that 5 ml of methanol was used for ~98% recovery of carbofuran and chloropyriphos pesticides from adsorbent surface. 5.7 Reusability of Adsorbents Several loading and elution experiments were takes place to test the stability of walnut shell. The adsorption efficiency was established practically constant (variation 1-5%) 6 cycles as shown in Fig. 12.
Fig. 12 Recycling of walnut shell for the adsorption of carbofuran and chloropyriphos 5.8 Analytical application to real water samples To eliminate carbofuran and chloropyriphos pesticide from surface water samples were collected from agricultural areas of Sindh province, the column method was applied. Surface water samples were spiked with 10 ppm of carbofuran and chloropyriphos and analysed by HPLC. Using present method carbofuran and chloropyriphos pesticides were effectively removed from surface water samples. The results with %adsorption and %recoveries are revealed in Table 6. Table 6 Percent adsorption and percent recoveries of carbofuran and chloropyriphos from surface water samples using walnut shell CONCLUSIONS
In the present work, attempt is made to develop a simplified adsorption method to remove toxic pesticides from water streams. Present work investigated indigenous, cost effective and effectual adsorbent i.e. walnut shell as a substitute of expensive adsorbents for the exclusion of pesticides. The effectiveness of the adsorbent was analysed by the conditions of pH, adsorbent dose, shaking speed, agitation time, temperature and
020406080100120024681012Number of cycles %Adsorption
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concentration of pesticides solutions. The adsorption of pesticide on investigated adsorbents is a first-order process, controlled by film diffusion. Fruendlich adsorption isotherm is best fitted to the adsorption data. Proposed method was successfully employed to remove investigated pesticides i.e. carbofuran and chloropyriphos from environmental water samples. Methanol was found suitable solvent to recover the adsorbed pesticides from the surface of adsorbent. The adsorption capacity of adsorbent was found practically constant after repeated use of more than 6 times. It is, therefore, recommended that costly synthetic adsorbents may be reinstating by these inexpensive and abundant adsorbents for the removal of toxic pesticides from water streams on large scale.
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