The document summarizes the synthesis and characterization of zeolite from coal fly ash and its application in removing inorganic and organic pollutants from wastewater. Key points:
- Zeolite was synthesized from coal fly ash via an alkali fusion process followed by hydrothermal treatment. The synthesized zeolite was characterized using various techniques.
- Batch adsorption studies were conducted to investigate the ability of synthesized zeolite to remove heavy metals like copper, cadmium, lead and dye (safranin) from wastewater. Parameters like contact time, dose, pH and concentration were optimized.
- Adsorption isotherm models like Langmuir, Freundlich, Tem
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.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications
New Analytical Technique For The Determination Of Mercury (II) By Synergistic...inventionjournals
A new technique was developed for the extractive spectrophotometric determination of mercury (II) by using newly synthesized chromogenic reagent N'',N'''-bis[(E)-(4-fluorophenyl)methylidene] thiocarbonohydrazide bis-(4-fluoroPM)TCH. It forms yellow colored ternary complex with mercury(II) in presence pyridine having composition 1:1:1 (M:Reagent:Py) in acidic pH range 1.7-3.7. The reagent is highly sensitive and selective towards mercury(II). So spectrophotometric method of mercury(II) is found to be very rapid, reliable and show synergistic effect. Absorption of colored organic layer in iso amyl acetate is measured with reagent blank at λmax 375 nm. Pyridine showed synergistic effect with reagent by the adduct formation in organic phase. Beer’s law was obeyed in the concentration range 0.25 to 3.5 µg mL-1 for mercury (II). Molar absorptivity and sandell’s sensitivity values of mercury(II)-bis-(4-fluoroPM)TCH-Py complex are 0.50127x105 lit mol-1 cm -1 and 0.004 µg cm -2 , respectively. The selectivity of the method was checked by using various foreign ions. The composition of the complex was determined by slope ratio method, mole ratio method and Job’s method of continuous variation. The colour of ternary complex was stable for more than 12 h. Various factors influencing on degree of comlexation are the effect of pH, reagent concentration, synergent concentration, equilibrium time, solvent were determined. The method was applicable for determination of mercury(II) in binary mixture, ternary mixture, ayurvedic sample, homoeopathic sample, industrial waste water, spiked water and dental unit waste water.
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.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications
New Analytical Technique For The Determination Of Mercury (II) By Synergistic...inventionjournals
A new technique was developed for the extractive spectrophotometric determination of mercury (II) by using newly synthesized chromogenic reagent N'',N'''-bis[(E)-(4-fluorophenyl)methylidene] thiocarbonohydrazide bis-(4-fluoroPM)TCH. It forms yellow colored ternary complex with mercury(II) in presence pyridine having composition 1:1:1 (M:Reagent:Py) in acidic pH range 1.7-3.7. The reagent is highly sensitive and selective towards mercury(II). So spectrophotometric method of mercury(II) is found to be very rapid, reliable and show synergistic effect. Absorption of colored organic layer in iso amyl acetate is measured with reagent blank at λmax 375 nm. Pyridine showed synergistic effect with reagent by the adduct formation in organic phase. Beer’s law was obeyed in the concentration range 0.25 to 3.5 µg mL-1 for mercury (II). Molar absorptivity and sandell’s sensitivity values of mercury(II)-bis-(4-fluoroPM)TCH-Py complex are 0.50127x105 lit mol-1 cm -1 and 0.004 µg cm -2 , respectively. The selectivity of the method was checked by using various foreign ions. The composition of the complex was determined by slope ratio method, mole ratio method and Job’s method of continuous variation. The colour of ternary complex was stable for more than 12 h. Various factors influencing on degree of comlexation are the effect of pH, reagent concentration, synergent concentration, equilibrium time, solvent were determined. The method was applicable for determination of mercury(II) in binary mixture, ternary mixture, ayurvedic sample, homoeopathic sample, industrial waste water, spiked water and dental unit waste water.
Removal of dye from polluted water using novel nano manganese oxide-based mat...Dr. Md. Aminul Islam
Dyes are priority pollutants, commonly found at significant concentrations in textile effluents. The presence of dyes stuffs in wastewater can cause severe problems to aquatic life and human beings. Therefore, the removal of dyes from wastewater is important in order to minimize their hazardous effects on the environment. One way of removing dyes is to use nanosized manganese oxides (MnOs). To date, there has been much work reported on the use of nanosized MnOs as sorbents for dyestuffs. They are promising sorbents for commercial use due to their amorphous nature, high specific surface areas (SSA), mesoporous structure, and low to the moderate point of zero charge (pHPZC). This review summarizes the toxicity and recent advances for removing dyes from wastewater using nanosized MnO sorbents. The article also describes the various experimental parameters necessary for adsorption optimization, such as adsorption time, pH, initial dye concentration, amount of sorbent and temperature. Adsorption mechanisms investigated by various modeling approaches are also discussed. In particular, it was observed that much work has been reported on the use of birnessite and its composites for dye removal. There are many papers reporting on the use of MnO in batch mode dye removal, but very few that report on the use of MnO in continuous column removal systems. Therefore, there is still a considerable need for further research to develop effective and economical large scale MnO column systems for commercial use.
Fertilizer plant waste carbon slurry has been investigated after some processing as an adsorbent for the removal of dyes and phenols using columns. The results show that the carbonaceous adsorbent prepared from carbon slurry being porous and having appreciable surface area (380 m2/g) can remove dyes both cationic (meldola blue, methylene blue, chrysoidine G, crystal violet) as well as anionic (ethyl orange, metanil yellow, acid blue 113), and phenols (phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol) fruitfully from water. The column type continuous flow operations were used to obtain the breakthrough curves. The breakthrough capacity, exhaustion capacity and degree of column utilization were evaluated from the plots. The results shows that the degree of column utilization for dyes lies in the range 60 to 76% while for phenols was in the range 53-58%. The exhaustion capacities were quite high as compared to the breakthrough capacities and were found to be 217, 211, 104, 126, 233, 248, 267 mg/g for meldola blue, crystal violet, chrysoidine G, methylene blue, ethyl orange, metanil yellow, acid blue 113, respectively and 25.6, 72.2, 82.2 and 197.3 mg/g for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, respectively
Modified magnetite nanoparticles with cetyltrimethylammonium bromide as super...Iranian Chemical Society
This paper reports application of cetyltrimethylammonium bromide (CTAB) coated magnetite nanoparticles (Fe3O4 NPs) as a novel adsorbent for removal of two types of disperse dyes, including disperse red 167, and disperse blue 183, from wastewater of textile companies. The effect of parameters including type of surfactant, pH of solution, surfactant concentration, and amount of salt, was investigated and optimized. The obtained results showed that the ratio of initial dye concentration to CTAB amounts has critical effect on removal processes so that removal efficiencies higher than 95% can be achieved even at high concentration of dyes as high as 500 mg l-1 when the ratio is optimum. Removal of dyes is very fast, and equilibrium is reached at times less than 10 min even for high concentration of the dyes. Very high adsorbent capacity (as high as 2000 mg g-1) was yielded for maximum tested concentration of the dyes (500 mg g-1). The obtained result was confirmed by thermogravimetric analysis data. This study showed that CTAB coated Fe3O4 NPs is a very efficient adsorbent for removal of dyes from wastewater of textile companies and has high capacity under optimum conditions.
Removal of Cu(II) Ions from Aqueous Solutions by Adsorption Onto Activated Ca...IJERA Editor
This paper studied the ability of using local activated carbon (LAC) derived from olive waste cakes as an
adsorbent for the removal of Cu(II) ions from aqueous solution by batch operation. Various operating parameters
such as solution pH, adsorbent dosage, initial metal ions concentration, and equilibrium contact time have been
studied. The results indicated that the adsorption of Cu(II) increased with the increasing pH, and the optimum
solution pH for the adsorption of Cu(II) was found to be 5. The adsorption process increases with increasing
dosage of LAC, also the amount of Cu(II) removed changes with Cu(II) initial concentration and contact time.
Adsorption was rapid and occurred within 25 min. for Cu(II) concentration range from 60 to 120 mg/l
isothermally at 30±1 oC. Maximum adsorption occurs at Cu(II) initial concentration lesser than 100 mg/l by
using adsorbent dosage (1.2 g/l). The equilibrium adsorption data for Cu(II) were fitted well with the Langmuir
and Freundlich adsorption isotherm models. The maximum adsorption capacity of LAC was found to be 106.383
mg/g. So, the results indicated the suitability use of the activated carbon derived from olive waste cakes (LAC)
as low cost and natural material for reliable removal of Cu(II) from water and wastewater effluents.
Removal of chromium (vi) by activated carbon derived from mangifera indicaeSAT 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
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.
Potato peels which are a low cost, renewable agroindustry by-product were used for the removal of hexavalent chromium from
aqueous effluents. Batch experiments were carried out with an artificial effluent comprising of potassium dichromate in deionised
water. The effects of the initial hexavalent chromium concentration, dose of biosorbent, and removal kinetics were explored. An
adsorbent dosage of 4 g/L was effective in complete removal of the metal ion, at pH 2.5, in 48 minutes. The kinetic process of
Cr(VI) adsorption onto potato peel powder was tested by applying pseudo-first-order and pseudo-second-order models as well as
the Elovich kinetic equation to correlate the experimental data and to determine the kinetic parameters. The adsorption data were
correlated by the Langmuir and Freundlich isotherms. A maximum monolayer adsorption capacity of 3.28 mg/g was calculated
using the Langmuir adsorption isotherm, suggesting a functional group limited adsorption process. The results confirmed that
potato peels are an effective biosorbent for the removal of hexavalent chromium from effluent.
Removal of Methylene Blue from Aqueous Solution by Adsorption using Low Cost ...ijsrd.com
The present study deals with removal of methylene blue (basic dye)from aqueous solution using a low cost activated carbon prepared from Delonix regia(gulmohar seed pods).Batch adsorption studies were conducted by varying the contact time adsorbent dosage and pH
Degradation of mono azo dye in aqueous solution using cast iron filingseSAT Journals
Abstract The mono-azo dye, Orange II, solution was substantially degraded with cast iron particles under varied conditions of experimental variables such as pH, initial dye concentration and cast iron dosage.At all solution pH studied, the degradation efficiency achieved was > 90%. With an initial dye concentration of 100 mg/L and optimum cast iron load of 28.56 g/L, the optimum degradation efficiency of 97.63% was achieved at pH 3. With same cast iron load and solution pH, more than 95% dye degradation efficiency was achieved at different initial Orange II concentrations ranging from 50-500 mg/L. The efficiency of cast iron particles in degrading Orange II dye was compared with that of pure elemental iron used in other study. Cast iron particles showed better degradation efficiencies than elemental iron that too at relatively lower dosages. Ultimately, from the results it can be inferred that cast iron fillings can be successfully applied to treat textile effluents containing high dye concentration and treatment efficiency can be enhanced by optimizing the reaction conditions. Index Terms: azo dyes, Orange II, degradation efficiency, cast iron fillings
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
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
This study aims to employ low-cost agro waste
biosorbent tamarind (Tamarindus indica) pod shells and
activated carbon prepared by complete and partial pyrolysis of
tamarind pod shell for the removal of hexavalent chromium
ions from aqueous solution. The effect of parameters namely,
initial metal ion concentration, pH, temperature, biomass
loading on chromium removal efficiency were studied. More
than 96.9% removal of Chromium was achieved using crude
tamarind pod shells as biosorbent. The experimental data
obtained were fitted with Langmuir, Freundlich, Temkin and
Redlich-Peterson adsorption isotherm models. The
experimental data fits well to Langmuir, Freundlich and
Temkin isotherms with regression coefficient R2 more than 0.9.
For Redlich-Peterson adsorption isotherm the experimental
data does not fit so well. The crude tamarind had maximum
monolayer adsorption capacity of 40 mg/g and a separation
factor of 0.0416 indicating it as best adsorbent among the three
tested adsorbent. Further, an attempt is made to fit sorption
kinetics with pseudo first order and pseudo second order
reactions. Pseudo second order kinetics model fits well to the
experimental data for all three adsorbents.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Removal of dye from polluted water using novel nano manganese oxide-based mat...Dr. Md. Aminul Islam
Dyes are priority pollutants, commonly found at significant concentrations in textile effluents. The presence of dyes stuffs in wastewater can cause severe problems to aquatic life and human beings. Therefore, the removal of dyes from wastewater is important in order to minimize their hazardous effects on the environment. One way of removing dyes is to use nanosized manganese oxides (MnOs). To date, there has been much work reported on the use of nanosized MnOs as sorbents for dyestuffs. They are promising sorbents for commercial use due to their amorphous nature, high specific surface areas (SSA), mesoporous structure, and low to the moderate point of zero charge (pHPZC). This review summarizes the toxicity and recent advances for removing dyes from wastewater using nanosized MnO sorbents. The article also describes the various experimental parameters necessary for adsorption optimization, such as adsorption time, pH, initial dye concentration, amount of sorbent and temperature. Adsorption mechanisms investigated by various modeling approaches are also discussed. In particular, it was observed that much work has been reported on the use of birnessite and its composites for dye removal. There are many papers reporting on the use of MnO in batch mode dye removal, but very few that report on the use of MnO in continuous column removal systems. Therefore, there is still a considerable need for further research to develop effective and economical large scale MnO column systems for commercial use.
Fertilizer plant waste carbon slurry has been investigated after some processing as an adsorbent for the removal of dyes and phenols using columns. The results show that the carbonaceous adsorbent prepared from carbon slurry being porous and having appreciable surface area (380 m2/g) can remove dyes both cationic (meldola blue, methylene blue, chrysoidine G, crystal violet) as well as anionic (ethyl orange, metanil yellow, acid blue 113), and phenols (phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol) fruitfully from water. The column type continuous flow operations were used to obtain the breakthrough curves. The breakthrough capacity, exhaustion capacity and degree of column utilization were evaluated from the plots. The results shows that the degree of column utilization for dyes lies in the range 60 to 76% while for phenols was in the range 53-58%. The exhaustion capacities were quite high as compared to the breakthrough capacities and were found to be 217, 211, 104, 126, 233, 248, 267 mg/g for meldola blue, crystal violet, chrysoidine G, methylene blue, ethyl orange, metanil yellow, acid blue 113, respectively and 25.6, 72.2, 82.2 and 197.3 mg/g for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, respectively
Modified magnetite nanoparticles with cetyltrimethylammonium bromide as super...Iranian Chemical Society
This paper reports application of cetyltrimethylammonium bromide (CTAB) coated magnetite nanoparticles (Fe3O4 NPs) as a novel adsorbent for removal of two types of disperse dyes, including disperse red 167, and disperse blue 183, from wastewater of textile companies. The effect of parameters including type of surfactant, pH of solution, surfactant concentration, and amount of salt, was investigated and optimized. The obtained results showed that the ratio of initial dye concentration to CTAB amounts has critical effect on removal processes so that removal efficiencies higher than 95% can be achieved even at high concentration of dyes as high as 500 mg l-1 when the ratio is optimum. Removal of dyes is very fast, and equilibrium is reached at times less than 10 min even for high concentration of the dyes. Very high adsorbent capacity (as high as 2000 mg g-1) was yielded for maximum tested concentration of the dyes (500 mg g-1). The obtained result was confirmed by thermogravimetric analysis data. This study showed that CTAB coated Fe3O4 NPs is a very efficient adsorbent for removal of dyes from wastewater of textile companies and has high capacity under optimum conditions.
Removal of Cu(II) Ions from Aqueous Solutions by Adsorption Onto Activated Ca...IJERA Editor
This paper studied the ability of using local activated carbon (LAC) derived from olive waste cakes as an
adsorbent for the removal of Cu(II) ions from aqueous solution by batch operation. Various operating parameters
such as solution pH, adsorbent dosage, initial metal ions concentration, and equilibrium contact time have been
studied. The results indicated that the adsorption of Cu(II) increased with the increasing pH, and the optimum
solution pH for the adsorption of Cu(II) was found to be 5. The adsorption process increases with increasing
dosage of LAC, also the amount of Cu(II) removed changes with Cu(II) initial concentration and contact time.
Adsorption was rapid and occurred within 25 min. for Cu(II) concentration range from 60 to 120 mg/l
isothermally at 30±1 oC. Maximum adsorption occurs at Cu(II) initial concentration lesser than 100 mg/l by
using adsorbent dosage (1.2 g/l). The equilibrium adsorption data for Cu(II) were fitted well with the Langmuir
and Freundlich adsorption isotherm models. The maximum adsorption capacity of LAC was found to be 106.383
mg/g. So, the results indicated the suitability use of the activated carbon derived from olive waste cakes (LAC)
as low cost and natural material for reliable removal of Cu(II) from water and wastewater effluents.
Removal of chromium (vi) by activated carbon derived from mangifera indicaeSAT 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
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.
Potato peels which are a low cost, renewable agroindustry by-product were used for the removal of hexavalent chromium from
aqueous effluents. Batch experiments were carried out with an artificial effluent comprising of potassium dichromate in deionised
water. The effects of the initial hexavalent chromium concentration, dose of biosorbent, and removal kinetics were explored. An
adsorbent dosage of 4 g/L was effective in complete removal of the metal ion, at pH 2.5, in 48 minutes. The kinetic process of
Cr(VI) adsorption onto potato peel powder was tested by applying pseudo-first-order and pseudo-second-order models as well as
the Elovich kinetic equation to correlate the experimental data and to determine the kinetic parameters. The adsorption data were
correlated by the Langmuir and Freundlich isotherms. A maximum monolayer adsorption capacity of 3.28 mg/g was calculated
using the Langmuir adsorption isotherm, suggesting a functional group limited adsorption process. The results confirmed that
potato peels are an effective biosorbent for the removal of hexavalent chromium from effluent.
Removal of Methylene Blue from Aqueous Solution by Adsorption using Low Cost ...ijsrd.com
The present study deals with removal of methylene blue (basic dye)from aqueous solution using a low cost activated carbon prepared from Delonix regia(gulmohar seed pods).Batch adsorption studies were conducted by varying the contact time adsorbent dosage and pH
Degradation of mono azo dye in aqueous solution using cast iron filingseSAT Journals
Abstract The mono-azo dye, Orange II, solution was substantially degraded with cast iron particles under varied conditions of experimental variables such as pH, initial dye concentration and cast iron dosage.At all solution pH studied, the degradation efficiency achieved was > 90%. With an initial dye concentration of 100 mg/L and optimum cast iron load of 28.56 g/L, the optimum degradation efficiency of 97.63% was achieved at pH 3. With same cast iron load and solution pH, more than 95% dye degradation efficiency was achieved at different initial Orange II concentrations ranging from 50-500 mg/L. The efficiency of cast iron particles in degrading Orange II dye was compared with that of pure elemental iron used in other study. Cast iron particles showed better degradation efficiencies than elemental iron that too at relatively lower dosages. Ultimately, from the results it can be inferred that cast iron fillings can be successfully applied to treat textile effluents containing high dye concentration and treatment efficiency can be enhanced by optimizing the reaction conditions. Index Terms: azo dyes, Orange II, degradation efficiency, cast iron fillings
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
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
This study aims to employ low-cost agro waste
biosorbent tamarind (Tamarindus indica) pod shells and
activated carbon prepared by complete and partial pyrolysis of
tamarind pod shell for the removal of hexavalent chromium
ions from aqueous solution. The effect of parameters namely,
initial metal ion concentration, pH, temperature, biomass
loading on chromium removal efficiency were studied. More
than 96.9% removal of Chromium was achieved using crude
tamarind pod shells as biosorbent. The experimental data
obtained were fitted with Langmuir, Freundlich, Temkin and
Redlich-Peterson adsorption isotherm models. The
experimental data fits well to Langmuir, Freundlich and
Temkin isotherms with regression coefficient R2 more than 0.9.
For Redlich-Peterson adsorption isotherm the experimental
data does not fit so well. The crude tamarind had maximum
monolayer adsorption capacity of 40 mg/g and a separation
factor of 0.0416 indicating it as best adsorbent among the three
tested adsorbent. Further, an attempt is made to fit sorption
kinetics with pseudo first order and pseudo second order
reactions. Pseudo second order kinetics model fits well to the
experimental data for all three adsorbents.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Isotherm Modeling and Thermodynamic Study of the Adsorption of Toxic Metal by...CrimsonpublishersEAES
Isotherm Modeling and Thermodynamic Study of the Adsorption of Toxic Metal by the Apricot Stone by Moussa Abbas*, Tounsia Aksil and Mohamed Trari in Environmental Analysis & Ecology Studies
Tannin gel derived from Leaves of Ricinus Communis as an adsorbent for the Re...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Reduction of toxicity from aqueous solution by low cost adsorbent: RSM method...Premier Publishers
Heavy metal pollution of waste water is a common environmental hazard, since the toxic metal ions dissolved can ultimately reach the top of the food chain and thus become a risk factor for human health. Chromium is present in waste water as trivalent and hexavalent. Trivalent chromium is relatively less toxic and less mobile while hexavalent chromium is toxic, carcinogenic, and mutagenic to animals as well as humans. Therefore, the removal of Cr (VI) from industrial waste water has been a research topic of great interest. In the present study carried out the comparative study of removal of the chromium (VI) from waste water by adsorption method. The search for new technologies involving the removal of toxic metals from wastewaters has directed attention to adsorption, based on metal binding capacities of various materials.
Application of emulsion liquid membranes for removal of Cd ,Co,Ni and Pb from...IOSR Journals
The paper points to the presence of heavy elements such as cobalt, nickel, lead and cadmium ratios of small but very harmful to the environment as well as health harmful if used by people for agricultural purposes, etc. This is the heavy elements harmful if it exceeds the limit as it is then used as components of the value after the extract has found these elements mentioned sources such as Ismailia Canal - Manzala Lake and the Red Sea, has been used as comparison tap water ELM for the separation of these elements has been selected cobalt (III) dicarbolide Span surfactant 80/85 and the use of acid silicon tungestic stage stripping effect concentrations of the carrier and the amendment, has been selected Co(III) dicarbolide because metal organic compound with a larger surface area and the distinction between the structure of certain net structure.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
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as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
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Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
1. SYNTHESIS AND CHARACTERIZATION OF ZEOLITE
FROM COAL FLY ASH AND ITS APPLICATION IN
REMOVAL OF INORGANIC AND ORGANIC
POLLUTANTS FROM WASTEWATER
SUPERVISOR PRESENTED BY
Dr. M. K. DWIVEDI PAYAL JAIN
GOVT. HOLKAR SCIENCE COLLEGE INDORE
2. INTRODUCTION
Coal fly ash (CFA) is a micro spherical particulate by- product of combustion of coal. It is primarily composed of
amorphous aluminosilicate and other crystalline minerals like mullite, quartz, haematite and magnetite [1].
Combustion of coal in thermal power stations produces over 1200 million tonnes of fly ash worldwide annually [2].
The disposal of such huge quantities of ash has become a problem [3].
Several approaches have been done for proper utilization of fly ash, for reduction of cost of disposal or for
minimizing environmental impact. The production of zeolites is one of the potential applications of CFA. The
aluminosilicate glass in CFA is a readily available source of Si and Al for zeolite synthesis so as to obtain high value
industrial products with environmental technological utilization [4].
Zeolites are three-dimensional, microporous, crystalline solids with well-defined structures that contain aluminium,
silicon, and oxygen in their regular framework; cations and water are located in the pores. Compositionally, zeolites
are similar to clay minerals. More specifically, both are alumino-silicates. They differ, however, in their crystalline
structure[5].
Due to rapid growth of industrialization and urbanization with technological advancement, the existing water
resources are becoming increasingly contaminated by discharge of effluent containing organics, colour, heavy
metals and other contaminants. It is discharged into water bodies from mining operation, metal plating and
tanneries
3. Heavy metal pollutant with density five times of water[6] has emerged due to anthropogenic activity which is the
prime cause of pollution, primarily due to mining the metal, smelting, foundries, and other industries that are metal-
based, leaching of metals from different sources such as landfills, waste dumps, excretion, livestock and chicken
manure, runoffs, automobiles and roadworks.
Heavy metals are potentially hazardous in combined or elemental forms. These are highly soluble in the aquatic
environments and therefore they can be absorbed easily by living organisms.
Chronic toxicity of Cadmium (Cd) in children includes damages of respiratory, renal, skeletal and cardiovascular systems
as well as development of cancers of the lungs, kidneys, prostate and stomach. The US EPA’s regulatory limit of Cd in
drinking water is 5 ppb or 0.005 parts per million (ppm). The WHO recommended safe limits of Cd in both wastewater
and soils for agriculture is 0.003 ppm[7].
Exposure to Lead (Pb) can occur through inhalation of contaminated dust particles and aerosols or by ingesting
contaminated food and water. Lead poisoning in humans damages the kidneys, liver, heart, brain, skeleton and the
nervous system The regulatory limit of Pb in drinking water according to US EPA is 15 ppb. The WHO recommended safe
limits of Pb in wastewater and soils used for agriculture are 0.01 and 0.1 ppm respectively[8].
4. A wide range of copper toxicities have been observed subsequent to accidental or iatrogenic poisonings or suicide
attempts: hepatic and renal failure, cirrhosis, haemolysis, vomiting, melena, hypotension, cardiovascular collapse,
stupor, and coma. The EPA’s established a limit of copper in drinking water as 1.3 ppm. The WHO recommended safe
limits of Cu in wastewater and soils used for agriculture are 0.025 and 0.1 ppm respectively[8].
Dyes or colouring substances are considered as one of the significant pollutants and they are stated as ‘visible
pollutant[9]. Textile effluents are major industrial polluters because of high color content, about 15% unfixed dyes
and salts[10].
Safranin is a popular and most ancient dye used in textile and silk industries , this dye is used to dye food and dessert
coloring, despite the benefits of this dye , but when discharge to the water it causes water pollution and respiratory
diseases skin and digestive tract infections on ingestion[11].
Hazardous pollutant are difficult to remove by conventional wastewater treatment, Possible methods of their
removal include chemical oxidation, froth flotation, adsorption, and coagulation etc. Among these, adsorption
currently appears to offer the best potential for overall treatment.
Zeolite being effective and reliable source of adsorption was synthesized from coal fly ash and applied to remove
heavy metals and dye in the thesis work.
5. The work reported in this thesis deals with the the removal of some heavy metals like Copper, Cadmium, Lead
and a dye Safranin by adsorption on zeolites material prepared from coal fly ash, with the following aims and
objectives:
1. To synthesize and employ zeolite from Coal fly ash by Alkali fusion followed by hydrothermal treatment.
2. To characterize the physio-chemical and textural properties of fly ash and Zeolite such as surface area, XRD,
XRF, FTIR and SEM .
3. To investigate the role of zeolite material in adsorption of dye and heavy metal containing wastewater.
4. To optimize the parameters of contact time, adsorbent dose, pH and initial adsorbate concentration and to
determine the applicability of Freundlich, Langmuir, Temkin, and Dubinin-Radushkevitch approach to
estimate design parameters characterizing the performance of the batch tests.
5. To determine the thermodynamic parameters to know the feasibility of the adsorption process.
6. To investigate the kinetic studies to have an understanding of the mechanistic process of the system.
6. MATERIALS AND METHODS
Coal fly ash that was collected from H.E.G. Thermal Power Station, Mandideep (Bhopal).
Chemicals used were supplied by Merck, India. The stock solutions were prepared in
deionized water supplied by Rankem. The standard calibration curves of known
concentrations of Safranin was plotted by finding out the absorbance at the characteristic
wavelength of λmax 518 nm and metals concentration was measured by Atomic absorption
Spectrophotometer (Perkin elmer-3100 series).
Safranin
7. PREPARATION OF ZEOLITE FROM FLY ASH
The direct hydrothermal method was used for the synthesis of zeolites since it is fast,
economic and less involving than the other fusion and microwave methods.
NaOH is added with coal fly ash in different ratios of 1:2, 1:1.5 and 1:1.2 and kept for
fusion at varying temperatures of 350°C,450° C and 550° C for 12 hours.
After this fusion mixtures were washed with double distilled water and agitated for 24
hours on magnetic stirrer to wash off excess of alkali, filtered on Whatmann filter
paper and dried in oven for 12 hours at 110°C and stored in desiccator before use.
9. ADSORPTION STUDIES
The adsorption was performed using the batch method. The equilibrium adsorption
uptake and percentage removal of adsorbates from the aqueous solution qe (mg/g)
were calculated using the following relationship:
Amount adsorbed qe =
Co−Ce V
W
………(1)
% Removal qe =
100 Co−Ce
Co
……… (2)
Where, Co is initial adsorbate concentration (mgL-1), Ce is equilibrium adsorbate
concentration (mgL-1), V is the volume of solution (L), W is the mass of adsorbent (g).
10. Adsorption Isotherms
The equilibrium data obtained in the present study were analyzed using Langmuir[12],
Freundlich[13], Dubinin-Radushkevich[14] and Temkin[15] isotherm models.
The rearranged Langmuir and Freundlich isotherm equations can be described as:
1
qe
=
1
qm
+ (
1
bqm
)(
1
Ce
) .............. (3)
log qe= log Kf +
1
n
log Ce. .............(4)
Where qm and b are the Langmuir constants related to maximum adsorption capacity and
energy of adsorption, respectively. Kf is a Freundlich constant related to the adsorption
capacity (mg/g) and n is an empirical constant.
11. Adsorption Isotherms….
The Dubinin-Radushkevich and Temkin isotherm models are as follows:
ln qe = ln qm – βE2 …………….(5)
qe =
RT
𝑏𝑇
ln 𝐴T𝐶e ……………(6)
Where β is Dubinin-Radushkevich constant, R is gas constant (8.31 Jmol−1 k−1), T is absolute
temperature, and E is mean adsorption energy (KJ mol-1). bT is Temkin constant which is
related to the heat of sorption (Jmol-1) and AT is Temkin isotherm constant (l g-1)
12. Thermodynamic Studies
Thermodynamic studies play an important role in understanding the process of
adsorption. This work computes the thermodynamic parameters of Gibbs Free
energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) of adsorption by carrying out the dye
adsorption process at 303 K. Thermodynamic parameters can also be evaluated by
using the data obtained from the adsorption isotherms.
log
b2
b1
=
ΔH0
R
[
T2−T1
T1T2
] ……… (7)
ΔG°= - 2.303 RT log b ……… (8)
ΔG° = ΔH° - TΔS° ………(9)
Where, b1 and b2 are Langmuir constants at different temperatures, R ideal gas
constant (8.314 J/mol/K), T1 and T2 are temperatures (K).
13. SPECIFIC RATE CONSTANT OF ADSORPTION:
The rate constant of adsorption for various adsorbates is determined from the following
first order rate expression given by Lagergren.
log (qe-q)= log qe -
Kad
2.303
t …………. (10)
Where q and qe are amounts of adsorbate adsorbed (mg/g) at time‘t’ and at equilibrium
respectively and Kad is the rate constant for adsorption (min-1). A straight line plot of log (qe-
q) versus t suggested the applicability of Lagergren equation. The rate constant of
adsorption (Kad) was calculated from the slope of the plot.
14. The pseudo second order (PSO) [16] kinetics model was used to investigate whether chemical reaction at the
adsorption site of zeolite was rate determining. The PSO model is given by:
t
q𝑡
=
1
K2
𝑞2
𝑒
+
t
q𝑒
…………. (11)
Where q𝑡 and q𝑒 are the amount of adsorbate per unit of adsorbent(mgg-1) at time t, and at equilibrium
respectively. K2 (g/mg.min) is the adsorption rate constant. From the slope and intercept of the (t/q𝑡) as a
function of t, K2 and q𝑒 can be obtained.
The Elovich[17] equation is mainly applicable for chemosorption kinetics the equation is often valid for
systems in which the adsorbing surface is heterogenous the model is expressed as
q𝑡=
1
β
ln(αβ)+
1
β
lnt ……………..(12)
Where α is initial adsorbate rate(mg g-1 min) and β is related to the extent of surface coverage and the
activation energy for chemosorption (g mg-1). A plot of q𝑡 vs ln t gives a linear trace with slope of (1/β )
and an intercept of 1/β ln (αβ).
15. Intra particle diffusion model
The intra particle diffusion model (Weber and Morris. 1962) was applied to describe the competitive
adsorption. In a liquid-solid system, the fractional uptake of the solute on particle varies according to a
fraction of D the diffusivity within the particle and r is the particle radius. The initial rate of intra
particle diffusion are obtained by linearization of the curve q𝑡 = f (𝑡0.5)[18]. The plot of qt against 𝑡0.5
may present multi-linearity. This indicates that two or more steps occur in the adsorption processes.
The first sharper portion is external surface adsorption or instantaneous adsorption stage. The second
portion is the gradual adsorption stage where the intra particle diffusion is rate-controlled. The third
portion is the final equilibrium stage, where the intra particle diffusion starts to slow down due to the
extremely low solute concentration in solution
The diffusion model is expressed as :
q𝑡= K𝑖𝑑 𝑡0.5+ C ……………(13)
Where K𝑖𝑑 (mg/g 𝑚𝑖𝑛0.5) is the intraparticle diffusion rate constant q𝑡 , the amount of adsorbate
absorbed at time t and C(mg/g), a constant proportional to thickness of boundary layer.
16. 0
r
Rate Expression:
According to the Fick's first law, the flux J(in moles per unit time and if, cross section, normal
to the path of flow) of the diffusing ion[19] can be expressed by equation (14)
…………..(14)
Where C is the concentration (in moles per unit volume), Di the effective diffusion coefficient
and r gives the direction along which transport is taking place.
Using the Fick’s second law, the governing differential equation for a spherical exchange bed
of radius ro in a solution can be expressed
……………….(15)
Using the proper boundary conditions, the solution of this equation has been obtained as an
infinite series i.e.
…………….(16)
r
C
D
J i
r
r
C
r
C
D
t
C
i
2
2
2
0
1
Q
Q
F t
17.
2
0
2
2
2
1
2
exp
1
6
1
r
n
t
D
n
i
n
Bt
n
n
n
2
2
1
2
exp
1
6
1
Where F = fractional attainment of equilibrium at time ‘t’
D = effective diffusion coefficient of ion in the adsorbent phase
r0 = radius of the adsorbent particle
2
0
2
r
D
B i
= time constant …….....……… (18)
and n = l,2,3..... are the integers defining the infinite series solution obtained for a Fourier
type of analysis.
………………….(17)
18. Thus knowing the value of B and mean particle radius r0 ,the effective diffusion coefficient Di can
be calculated for an adsorption system.
From equation (17), the plot of Bt versus t must be straight line (of slope B) passing through the
origin provided the exchange rate is governed by particle-diffusion mechanism [20].
It is to be noted that the treatment is same with particle diffusion as controlling process as that
for isotopic exchange for which equation (17) is developed except that the self-diffusion
coefficient is replaced by effective diffusion coefficient of exchange ions [21].
The fractional attainment of equilibrium is determined by
…………….(19)
Where Qt= amount adsorbed after time‘t’
Q = amount adsorbed after infinite time or at equilibrium.
Reichenberg’s table[22] is used to obtain the corresponding Bt values for every observed value of
F.
Q
Q
F t
19. To distinguish between the film and particle diffusion controlled rates of adsorption, the
linearity test of Bt versus t plot have been used and in these studies the experimental
conditions were set up for particle-diffusion mechanism as the rate determining step.
The linear behaviour of log Di versus l/T plot permits the use of Arrhenius equation.
……………..(20)
From the slope and intercept of the linear plot of energy of activation Ea and D0 values of
the process have been calculated. The values obtained for D0 have been used to calculate
the entropy of activation S# using the following equation.
……………(21)
Where k, h and R are the usual constants and d is the distance between the adsorbing sites
of the adsorbent. Conventionally, it is taken as equal to 5 x10-8 cm.
RT
E
D
D a
i exp
0
R
S
h
kT
d
D
#
2
0 exp
72
.
2
20. The mass transfer study: The mass transfer coefficient values (βL) for the adsorption of
Copper, Cadmium, Lead and Safranin on Zeolite at 250 C were calculated graphically (fig.
38, 39 and 40) by using equation (mass transfer coefficient equation) .
ln [Ct/Co – 1/ 1+mk] = ln mk/1+mk – 1+mk/mk βLSst ……………….(22)
Ss = C0m / (1-€p) dpϼp ………………..(23)
Where, Ct = concentration of adsorbate after time t
C0 = Initial adsorbate concentration
M = mass of adsorbent per unit volume of particle free adsorbent solution
k = Langmuir constant obtained by multiplying adsorption capacity Qm and adsorption
energy b
βL = Mass transfer coefficient
Ss = Outer surface of the adsorbent per unit volume
€p = Porosity of adsorbent
dp = Particle diameter (cm)
ϼp = Density of adsorbent
21. RESULTS AND DISCUSSION
CHARACTERIZATION OF THE ADSORBENT
XRF Analysis:
The chemical composition of fly ash determined by WDXRF are shown in Table 1 which
depicts that the major constituents of the fly ash .The fly ash mainly contains silica and
alumina with SiO2 to Al2O3 ratio of 2.43 which is consistent with other fly ash (class F)
samples used in literature to synthesize zeolites. Therefore coal fly ash is suitable as raw
material for zeolite synthesis. There was increase in the percentage of Na2O (from 1.23 to
6.19%) in synthesized zeolite compared to coal fly ash. This is due to involvement of Na+
ions required to neutralize the negative charge on aluminate in zeolite.
23. EDX Analysis:
Energy-dispersive X-ray spectroscopy (EDX) is an analytical technique used for the
elemental analysis of a sample.
(a) Untreated fly ash (b) Zeolite
Fig 1 : Representing EDX analysis
24. XRD Analysis:
The X-ray diffraction (XRD) patterns of fly ash and synthesized zeolite material were
obtained using a Philips X-ray diffractometer (Philips BW1710). Operating conditions
involved the use of Cu K α radiation at 4 kV and 30 mA. The samples were scanned from
10–90° (2θ, where θ is the angle of diffraction). Various crystalline phases present in the
samples were identified with the help of JCPDS files number(39-0219) for inorganic
compounds. Quantitative measure of the crystallinity of the synthesized zeolite was
made by using the summed heights of major peaks in the X-ray diffraction pattern
(Szostak 1976). The major peaks were selected specifically because they are least
affected by the degree of hydration of samples and also by others.
25. XRD of Coal fly ash XRD of zeolite at 550oC
As shown in fig. 2 the XRD pattern of CFA mainly consist of crystalline quartz and mullite phases, CFA is
primarily consist of amorphous material. The lower diffraction angles in CFA is due to the amorphous phases.
After the synthesis of zeolite from CFA, many sharp diffraction peaks of high intensity emerges which confirm
the formation of zeolite. The phases were identified by comparing with other diffractograms from literature
obtained by using inorganic index to the powder diffraction of JCPDS.
The XRD pattern of zeolite indicates that the NaP type of zeolite was synthesised (Na3Al6Si10O32. 12H2O)
Fig 2 : Analysis of XRD
26. SEM Analysis:
The morphological structure of the untreated fly ash, and synthesized zeolite material
were obtained by using scanning electron micrograph (Jeol, JSM 5800). The bulk
composition was also estimated from SEM by indirect method. The results were further
verified by X-ray fluorescence (XRF) data.
(a) Untreated CFA (b) Zeolite
Fig 3 : SEM Analysis
27. FTIR Analysis:
Based on the spectrum obtained from Fourier transform infra-red (FTIR) analysis of fly ash
and AAF as shown in fig. 4, it is observed that there are significant changes in the
intensities and the width of various bands due to interaction of fly ash with alkali. It can
be noticed that there is an increase in intensity and broadness of the stretching
frequency OH band at 3452 cm-1 after the treatment. This can be attributed to an
increase in hydrated products due to the reaction between amorphous silicate and the
alkali. Further the shift in the frequency to lower values indicates change in acidic
character of the terminal Si-OH group.
Coal fly ash zeolite material
Fig 4: FTIR Analysis of CFA and zeolite
3452
1000-1076
400-434
603
28. Moreover, asymmetrical stretching of TO4 (SiO4 and AlO4) band corresponding to the
variation in frequency from 1076 to 1000 cm-1 and the increase in its sharpness
confirms synthesis of silicates and change in its acidic characteristics. This can be
attributed to substitution of Si+4 by Al+3 in some of the tetrahedral framework of the
primary building units of the aluminosilicates and their external linkage with the Na+
ions due to their interaction with the alkali .The band at 434 cm-1 indicates the
increased crystallization of product.
Based on FTIR spectrum in fig. 4, it can be observed that there is presence of pore
opening corresponding to frequency range from 420-400 cm-1in the zeolite which can
be attributed to the dissolution of minerals present in the fly ash and precipitation of
zeolite.
29. BATCH STUDIES
Safranin
Influence of contact time:
The effect of contact time was studied at Safranin dye concentrations of 5 and 10, 20mg/l with
a fixed adsorbent dose of 5 g/l at 298 K and natural pH of 6.8. The contact time was varied from
15 min to 300 min for both the concentrations studied and the percentage efficiency was
calculated. The results of contact time on adsorption efficiency plotted in figure 5 .
A perusal of figure 5 indicates that the efficiency of dye adsorbed was rapid in initial stage up
to 180 min and after that remains almost constant due to saturation of the active sites which do
not allow further adsorption to take place. It is also observed that at higher concentration of
Safranin (10 mg/l), the adsorption efficiency is high (82.4 %) as compared to the maximum
efficiency of 79.7 % for 5 mg/l after 180 min of contact time. The observed increase in the
adsorption of dyestuffs with increasing concentration may be due to availability of sufficient
adsorption sites at adsorbent. The optimal contact time to attain equilibrium was
experimentally found to be about 180 min.
30. The effect of contact time was studied for metal ions including Copper, Cadmium and
lead at concentrations of 100 and 500 mg/l with a fixed adsorbent dose of 5 g/l at 298 K
for Copper and 10g/l For Cadmium and Lead at natural pH. The contact time was varied
from 15 min to 300 min for both the concentrations studied and the percentage
efficiency was calculated. The results of contact time on adsorption efficiency plotted in
figure 5. A perusal of fig. 5 (a-d) indicates that the efficiency of adsorption was rapid in
initial stage up to 240, 90, 120 min for Cu, Cd, Pb respectively and after that remains
almost constant due to saturation of the active sites which do not allow further
adsorption to take place.
31. (a) (b)
(c ) (d)
Fig 5 : Contact time for (a) Safranin (b) Copper (c) Cadmium and (d) Lead
32. Influence of pH
To determine the optimum pH conditions for the adsorption of safranin on zeolite
material, the effect of pH was observed over the pH range (4.0–10.0). The studies were
conducted at a fixed concentration of adsorbate (5 mg/l), contact time (180 min) and
adsorbent dose 5 g/l at 323 K. The results obtained are presented in fig. 6 which show
that adsorption of safranin increases with increase in pH from 4.0 to 9.0 and after that no
appreciable change has been observed on further increase in pH to 10.0. Maximum
adsorption of Safranin is 90.3 % at an optimum pH of 9.0.
Similarly optimum pH for metal ions was studied over a range (4.0-10.0) for copper and
lead and (2.0-10.0) for cadmium. Studies conducted on fixed adsorbate dose of (10g/l) for
cadmium and lead, (5g/l) for copper, contact time (240, 90, 120 min) for Cu, Cd, Pb
respectively were studied on adsorbent dose of 100 and 500 ppm at 298 K.
The result obtained in fig. (7-9) show that adsorption of metal ions increase with increase
in pH and after no appreciable change is observed on further increase of pH to 6,5 and 5
for Cu, Cd, Pb respectively.
Maximum adsorption of metal ions (Cu, Cd, Pb) was of 95.7%, 85.1%, 89.7% respectively
at pH of 6,5,5 respectively.
33. Fig:6 Influence of pH on uptake of Safranin Fig 7:Influence of pH on uptake of in Copper
Fig 8:Influence of pH on uptake of in Cadmium Fig 9: Influence of pH on uptake of in Lead
34. Influence of adsorbent dosage:
In order to investigate the effect of mass of adsorbent on the adsorption of safranin, a
series of adsorption experiments was carried out with different adsorbent dosage at an
initial dye concentration of 10 mg/l. Fig. 10 shows the effect of adsorbent dosage on
the removal of safranin. The percentage removal of safranin increased with the
increase in adsorbent initially from 5 g/l to 10g/l. This can be attributed to increased
adsorbent surface area and availability of more adsorption sites resulting from the
increase adsorbent dosage. But on increasing it further the adsorption efficiency is
reduced. It may be due to the overcrowding of adsorbate molecules which prevent the
diffusion through the actual adsorption sites.
Similarly fig. 11 and 12 (a-b) represents the effect of adsorbent dosage on the removal
of Copper, Cadmium and Lead respectively.
35. Fig:10 Influence of adsorbent dose on uptake of Safranin Fig 11:Influence of adsorbent dose on uptake of Copper
Fig 12(a): Influence of adsorbent dose on uptake of Cadmium Fig 12 (b): Influence of adsorbent dose on uptake of Lead
36. Influence of initial adsorbate concentration and temperature:
The effect of initial concentration of safranin between the ranges of 5 to 60 mg/l was
carried out to observe the absorption efficiency at a fixed adsorbent dosage (5 g/l) and
temperature (298 and 323 K). The pH was maintained at 9.0 and contact time was kept
180 min. The results of the studies are shown in fig. 13 (a) which depict that dye uptake
increases with increase in initial Safranin concentration from 5 to 60 mg/l and thereafter
equilibrium is achieved in dye uptake efficiency at a concentration of 50 mg/l at 298 and
323K. The increment in sorption capacity may be due to the increase of dye
concentration which resulted in higher concentration gradient of the dye, thus leading to
higher sorption capacity. The rate of uptake of dye was found to decrease with increase
in temperature, thereby indicating the process to be exothermic in nature. This decrease
in adsorption efficiency on increase in temperature may be due to the weakening of
adsorptive forces between the active sites of the adsorbent and adsorbate.
Similarly fig. 13(b) and 14(c-d) represents Metal uptake with increase in concentration
from 100-500 ppm.
37. (c ) (d)
Fig 13 (a),(b) Influence of initial adsorbate concentration and temperature on uptake of Safranin and Copper
Fig 14 (c),(d) Influence of initial adsorbate concentration and temperature on uptake of Cadmium and Lead
(a) (b)
38. Adsorption Isotherms:
Langmuir, Freundlich, Temkin and D-R isotherm models have been used to evaluate
the adsorption data for all adsorbates.
The values of the regression coefficients in fig (15-18) for safranin indicate that the
experimental data satisfactorily follows order: Freundlich>Langmuir>D-R> Temkin at
298K. The values of Langmuir, Freundlich, Temkin and D-R constant are given in the
Table 2.
The values of the regression coefficients in fig (19-22) for copper indicate that the
experimental data satisfactorily follows order: Langmuir>D-R> Freundlich> Temkin at
298K. The values of Langmuir, Freundlich, Temkin and D-R constant are given in the
Table 3.
39. Adsorption Isotherms:
The values of the regression coefficients in fig (23-26) for cadmium indicate that the
experimental data satisfactorily follows order: Langmuir>D-R> Freundlich> Temkin at
298K. The values of Langmuir, Freundlich, Temkin and D-R constant are given in the
Table 4.
The values of the regression coefficients in fig (27-30) for Lead indicate that the
experimental data satisfactorily follows order: Freundlich>D-R> Langmuir> Temkin at
298K. The values of Langmuir, Freundlich, Temkin and D-R constant are given in the
Table 5.
40. (a) (b)
Fig : 15 Langmuir isotherm plot of Safranin at (a) 298 and (b) 323 K
Fig : 16 Freundlich Isotherm plot of Safranin at (c) 298 and (d) 323 K
(c) (d)
41. (a) (b)
(c) (d)
Fig : 17 Temkin isotherm plot of safranin (a) at 298K and (b) at 323K
Fig : 18 Dubinin-Radushkevitch (D-R) of safranin (c) at 298 K and (d) at 323K
42. (a) (b)
Fig : 19 Langmuir isotherm plot of Copper at (a) 298 and (b) 323 K
Fig :20 Freundlich Isotherm plot of Copper at (c) 298 and (d) 323 K
(c) (d)
43. (a) (b)
(c) (d)
Fig : 21 Temkin isotherm plot of Copper (a) at 298K and (b) at 323K
Fig : 22 Dubinin-Radushkevitch (D-R) of Copper (c) at 298 K and (d) at 323K
44. (a) (b)
Fig :23 Langmuir isotherm plot of Cadmium at (a) 298 and (b) 323 K
Fig :24 Freundlich Isotherm plot of Cadmium at (c) 298 and (d) 323 K
(c) (d)
45. Fig: 25 Temkin isotherm plot of Cadmium (a) at 298K and (b) at 323K
Fig: 26 Dubinin-Radushkevitch (D-R) of Cadmium (c) at 298 K and (d) at 323K
(a) (b)
(c) (d)
46. (a) (b)
Fig : 27 Langmuir isotherm plot of Lead at (a) 298 and (b) 323 K
Fig : 28 Freundlich Isotherm plot of Lead at (c) 298 and (d) 323 K
(c) (d)
47. Fig : 29 Temkin isotherm plot of Lead (a) at 298K and (b) at 323K
Fig : 30 Dubinin-Radushkevitch (D-R) of Lead (c) at 298 K and (d) at 323K
(a) (b)
(c) (d)
48. At 298 K At 323 K
Langmuir qm mg-g
-1
7.14 Langmuir qm mg-g
-1
5.52
b 1.0687 b 1.1242
R
2
0.979 R
2
0.918
RL 0.1576 RL 0.151
Frendlich KF mg-g
-1
3.79 Frendlich KF mg-g
-1
2.432
1/n 0.758 1/n 0.631
R
2
0.982 R
2
0.976
Temkin At L-mg
-1
6.4867 Temkin At L-mg
-1
4.41217
bt J-mol
-1
1140.16 bt J-mol
-1
1291.68
9
Bt 2.173 Bt 2.079
R
2
0.9 R
2
0.814
Dubinin-
Radushkevich qDR mol-g
-1
8.7146
Dubinin-
Radushkevich qDR mol-g
-1
4.77789
β
(mol-g
-
1
)
2
9×10
-8
β (mol-g
-1
)
2
8×10
-8
E KJ-mol
-1
2.357 E KJ-mol
-1
2.5
R
2
0.959 R
2
0.666
Table 2 : Langmuir, Frendlich, Temkin, Dubinin-Radushkevich isotherm parameters of Safranin adsorption system
49. At 298 K At 323 K
Langmuir qm mg-g
-1
90.9 Langmuir qm mg-g
-1
166.66
b 11 b 2
R
2
961 R
2
0.959
RL 0.01785 RL 0.0909
Frendlich KF mg-g
-1
113 Frendlich KF mg-g
-1
135.2
1/n 0.552 1/n 0.704
R
2
0.909 R
2
0.975
Temkin At L-mg
-1
0.4245 Temkin At L-mg
-1
0.233
bt J-mol
-1
102.379 Bt J-mol
-1
84.3411
Bt 24.2 Bt 31.84
R
2
0.798 R
2
0.955
Dubinin-
Radushkevich qDR mol-g
-1
248.88
Dubinin-
Radushkevich qDR mol-g
-1
400.2142
β (mol-g
-1
)
2
7×10
-9
β (mol-g
-1
)
2
8×10
-7
E KJ-mol
-1
8.451 E KJ-mol
-1
7.905
R
2
0.909 R
2
0.977
Table 3 : Langmuir, Frendlich, Temkin, Dubinin-Radushkevich isotherm parameters of Copper adsorption system
50. At 298 K At 323 K
Langmuir qm mg-g
-1
58.82 Langmuir qm mg-g
-1
41.66
b 1.133 b 1.2
R
2
0.995 R
2
0.989
RL 0.0811 RL 0.0769
Frendlich KF mg-g
-1
31.55 Frendlich KF mg-g
-1
22.33
1/n 0.6561 1/n 0.615
R
2
0.984 R
2
0.997
Temkin At L-mg
-1
0.1113 Temkin At L-mg
-1
0.08702
bt J-mol
-1
192.2 bt J-mol
-1
251.208
Bt 12.89 Bt 10.69
R
2
0.979 R
2
0.964
Dubinin-
Radushkevich qDR mol-g
-1
116.745
Dubinin-
Radushkevich qDR mol-g
-1
81.695
β (mol-g
-1
)
2
1×10
-8
β (mol-g
-1
)
2
8×10
-9
E KJ-mol
-1
7.071 E KJ-mol
-1
7.905
R
2
0.957 R
2
0.994
Table 4: Langmuir, Frendlich, Temkin, Dubinin-Radushkevich isotherm parameters of Cadmium adsorption system
51. At 298 K At 323 k
Langmuir qm mg-g
-1
50 Langmuir qm mg-g
-1
66.66
b 2.22 b 15
R
2
0.99 R
2
0.996
RL 0.0431 RL 0.0066
Frendlich KF mg-g
-1
36.81 Frendlich KF mg-g
-1
174.2
1/n 0.588 1/n 0.6188
R
2
0.996 R
2
0.991
Temkin At L-mg
-1
0.15837 Temkin At L-mg
-1
0.08702
bt J-mol
-1
194.776 bt J-mol
-1
251.208
Bt 12.72 Bt 15.33
R
2
0.96 R
2
0.982
Dubinin-
Radushkevich qDR mol-g
-1
115.3533
Dubinin-
Radushkevich qDR mol-g
-1
275.063
β (mol-g
-1
)
2
9×10
-9
β (mol-g
-1
)
2
5×10
-9
E KJ-mol
-1
7.453 E KJ-mol
-1
10
R
2
0.995 R
2
0.995
Table 5: Langmuir, Frendlich, Temkin, Dubinin-Radushkevich isotherm parameters of Lead adsorption system
52. Thermodynamic Parameters:
SAFRANIN
Thermodynamic parameters can also be evaluated by using the data obtained from
the adsorption isotherms. The change in standard free energy (ΔG0), Enthalpy (ΔH0)
and entropy (ΔS0) of adsorption for Safranin was calculated by known methods and
the values are given in Table 6. The negative free energy value indicates the feasibility
of the process and spontaneous nature of adsorption. Positive enthalpy value
indicates the process to be endothermic. Positive entropy value supports the affinity
of the adsorbent material with the adsorbate.
ΔG0 (KJmole-1) ΔH0 (KJmole-1) ΔS0 (KJmole-1K-1)
-0.14439 1.762 6.39
Table 6: Thermodynamic Parameters for Safranin
53. Thermodynamic Parameters:
COPPER
Thermodynamic parameters can also be evaluated by using the data obtained from
the adsorption isotherms. The change in standard free energy (ΔG0), Enthalpy (ΔH0)
and entropy (ΔS0) of adsorption for copper was calculated by known methods and the
values are given in Table 7. The negative free energy value indicates the feasibility of
the process and spontaneous nature of adsorption. Negative enthalpy value indicates
the process to be exothermic. Negative entropy value supports the affinity of the
adsorbent material with the adsorbate.
ΔG0 (KJmole-1) ΔH0 (KJmole-1) ΔS0 (KJmole-1K-1)
-5.94 -54.6 -163.2
Table 7: Thermodynamic Parameters for Copper
54. Thermodynamic Parameters:
CADMIUM
Thermodynamic parameters can also be evaluated by using the data obtained from
the adsorption isotherms. The change in standard free energy (ΔG0), Enthalpy (ΔH0)
and entropy (ΔS0) of adsorption for Cadmium was calculated by known methods and
the values are given in Table 8. The negative free energy value indicates the feasibility
of the process and spontaneous nature of adsorption. Positive enthalpy value
indicates the process to be endothermic. Positive entropy value supports the affinity
of the adsorbent material with the adsorbate.
ΔG0 (KJmole-1) ΔH0 (KJmole-1) ΔS0 (KJmole-1K-1)
-0.309 1.839 7.213
Table 8: Thermodynamic Parameters for Cadmium
55. Thermodynamic Parameters:
LEAD
Thermodynamic parameters can also be evaluated by using the data obtained from
the adsorption isotherms. The change in standard free energy (ΔG0), Enthalpy (ΔH0)
and entropy (ΔS0) of adsorption for Safranin was calculated by known methods and
the values are given in Table 9. The negative free energy value indicates the feasibility
of the process and spontaneous nature of adsorption. Positive enthalpy value
indicates the process to be endothermic. Positive entropy value supports the affinity
of the adsorbent material with the adsorbate.
ΔG0 (KJmole-1) ΔH0 (KJmole-1) ΔS0 (KJmole-1K-1)
-19.76 61.167 271.56
Table 9: Thermodynamic Parameters for Lead
56. Kinetic studies:
Rate Constant of Adsorption:
The linear nature of the plots of log(qe-q) versus time for safranin, Copper,
cadmium and lead at 298K fig. 31 show the applicability of the first order rate
expression equation of Lagergren. The values of rate constant of adsorption (Kad)
were also calculated and are presented in Table 10 .
Adsorbate Kad (min-1)
COPPER
CADMIUM
LEAD
SAFRANIN
0.0115
0.039
0.0207
0.016
Table 10: Legergren constant for Safranin, Copper, cadmium and Lead
57. (a) (b)
(c) (d)
Figure 31 : Legergren plots for (a)safranin, (b)copper, (c)cadmium and (d) lead
58. Pseudo Second Order Model
The pseudo second order equation was based on adsorption capacity at equilibrium.
From the slope and intercept of the (t/qt) as a function of t, the plot provided excellent
linearity R2 > 0.99. K and qe values for Safranin, Copper, Cadmium and Lead at 250C was
mentioned in Table 11. Fig. 32 showed the applicability of the pseudo second order rate
expression equation.
Adsorbate K (mg g-1min-1) R2
Safranin 1.726 0.999
Copper 5.35 X 10-3 0.999
Cadmium 2.11 X 10-2 0.999
Lead 1.95 X 10-2 0.998
Table 11: Rate Constants of Adsorption (K) of PSO at 298 K
59. (a) (b)
( c) (d)
Figure 32 : Pseudo second order plots for (a) Safranin, (b) copper, (c ) Cadmium, (d) lead
60. Elovich Model
Elovich equation was mainly applicable for chemo adsorption kinetics. The equation was
often valid for systems in which the adsorbing surface was heterogenous. Fig 33 showed
plot of (qt) vs. (ln t) with a linear slope of 1/β and intercept of 1/β ln (α β). The results of
Elovich plot at various concentrations of Safranin, Copper, Cadmium and lead were cited
in Table 12.
Adsorbate α (mg g-1 min-1) β (mg g-1) R2
Safranin 9.45 X 1030 83.33 0.9876
Copper 2185.62 0.667 0.9962
Cadmium 138.03 1.126 0.9815
Lead 3757.16 1.522 0.9291
Table 12: Parameters of Elovich model
61. Figure 33: plots of Elovich for (a) Safranin ,(b) Copper, ( c) Cadmium and (d) Lead
(a) (b)
(c ) (d)
62. Intraparticle Diffusion Model
This model was applied to describe the competitive adsorption. The initial rate of diffusion
was obtained by linearization of the curve (qt) Vs (t0.5). The plot of (qt) against (t0.5) for
Safranin, Copper, Cadmium and Lead showed competitive adsorption occurring in solution
Fig. 34. The linear portion of plot for wide range of contact time between adsorbent and
adsorbate did not pass through the origin. The variation from the origin or near saturation
might be due to the variation of mass transfer in the initial and final stage of adsorption.
The values are given in Table 13.
Adsorbate Kdiff (mg g-1 min) Xi R2
Safranin 0.003 0.93 0.9635
Copper 0.302 14.63 0.9684
Cadmium 0.302 5.73 0.9877
Lead 0.198 6.78 0.9805
Table 13: Parameters of Intraparticle Diffusion Model
63. (a) (b)
(c ) (d)
Figure 34: Intraparticle plots for (a) Safranin, (b) Copper, (c ) Cadmium and (d) Lead
64. Rate expression and treatment of data:
The dispersion coefficient of specific species depends upon its size, valance and compound nature. It likewise
depends on the charge density, mesh width, level of swelling and chemical nature of the framework of
adsorbent. Moreover, the composition of the pour fluid and temperature influences the diffusion coefficient.
Different components are additionally responsible for reducing the mobility of certain species in the pores. It
was observed that the retardation was more prominent on polyvalent than monovalent particles. This
distinction was noticed in all identical environments.
A favourable explanation was the electrostatic attraction on the ingoing particle by the fixed ionic group of
the adsorbent which normally is stronger on polyvalent particle. The retarding interaction within the
framework might also be other than electrostatic forces. Now and again some particular compound
collaborations might bring about a lower mobility of the species in question. A comparative impact can be
seen, because of London dispersion forces acting between the species and the matrix.
65. • It was found that Bt versus time plots for Cd2+, Cu2+, Pb2+ ions at different adsorbate concentrations were linear
and did not pass through the origin indicating the process to be film diffusing in nature. To confirm this
assumption, Mckay plots at different adsorbate concentrations had been drawn utilizing the least square
principle. Mckay plots were linear for these ions showing a film diffusion process.
• For Safranin, Bt versus time plots (Fig. 35) were linear at lower concentrations (5 ppm) but did not pass through
the origin indicating the process to be film-diffusion in nature. But at higher concentrations (≥10 ppm) the plots
obtained were curved and passed through the origin. The same could however be resolved into two linear plots
with different slops, thereby indicating the change in mechanism.
• The initial portion passes through the origin and has a smaller slope thus reflecting that the effective diffusion
coefficient was smaller, and the particle-diffusion mechanism was the rate limiting step. However, at a later
stage, the slop and consequently the effective diffusion coefficient increases and the line does not pass
through the origin. At this stage the process might not be purely particle-diffusion controlled, other factors like
micelle formation might also become effective.
66. • The increase in effective diffusion coefficient was due to an increase in the number of occupied
sites. To confirm this assumption, Mckay plots ( Fig. 36) at different adsorbate concentrations, have
been drawn utilizing the least square principle. Mckay plot was linear at lower concentration (5
ppm) which indicated the film-diffusion process. Mckay plots at higher concentrations (≥10 ppm)
were curved which justified the assumption that particle-diffusion process was the rate limiting
step.
67. Fig. 35: Plot of Bt versus Time for (a) Safranin, (b) Copper (c ) Cadmium and (d) Lead
(a) (b)
(c) (d)
68. Figure 36: Mckay plots of (a) Safranin, (b) Copper, (c) Cadmium (d) lead at various adsorbate concentration
(a) (b)
(c ) (d)
69. Diffusion coefficient
The effective diffusion coefficient values at 250C, 400C and 500C were calculated for
copper, cadmium, lead and safranin (Table 14) . It has been found that the Di
decreases with increase in temperature. It is due to increase in mobility of ions and
increase in the retarding force acting on the diffusing ions results in an de-
enhancement of Di with temperature fig.37 represent trend for Safranin, Copper,
Cadmium and Lead respectively.
The effective diffusion coefficient values observed in the present investigations, are
greater than those reported in case of hydrous ferric oxide (10-17 m2 sec-1) and clay
Montmorillonite (10-18 m2 sec-1). This leads to the inference that the channels in
the developed zeolite material are wider than those of hydrous oxides mentioned
above.
70. (a) (b)
( c) (d)
Figure 37: Plot of Di versus 1/T for (a)Safranin (b) Copper ( c) Cadmium and (d) Lead
71. Table: 14 Values of the effective diffusion coefficient (Di) at different temperatures
Adsorbate
Di(m2s-1)
298K (250C) 313K (400C) 323K (500C)
Safranin 2.11×10-10 2.20×10-10 2.29×10-10
Copper 1.89×10-10 1.93×10-10 2.04×10-10
Cadmium 9.26×10-12 1.02×10-11 1.16×10-11
Lead 2.61×10-12 2.85×10-12 3.09×10-12
72. The pre-exponential constant (Do), energy of activation (Ea) and entropy of
activation (∆S#) for the diffusion of Copper, Cadmium, Lead and Safranin were
calculated and are given in Table 15. The Values of entropy of activation (∆S#)
obtained for the exchange of Cadmium and Lead are positive. The values thus
indicate that the no significant change in the internal structure of the adsorbent
material was found during the exchange of ions .
Table 15 : Do, Ea and ∆S# values for the diffusion of adsorbates
Adsorbate Do (m2s-1) Ea (KJmole-1) ∆S# (KJ-1mole-1)
Safranin 5.9×10-10 2.5 x 10-3 -0.073
Copper 4.6×10-10 2.2 x 10-3 -0.075
Cadmium 1.6×10-10 7.1 x 10-2 0.085
Lead 2.2×10-11 5.3 x 10-3 0.101
73. The Mass transfer studies
The mass transfer coefficient values (βL) for the adsorption of Safranin, Copper, Cadmium and Lead on
Zeolite at 250C were calculated graphically by using mass transfer coefficient equation and reported in the
Table 16.
The linear nature of the plots (fig.38(a-d)) for all the adsorbates studied suggested the validity of the
diffusion model. The values of mass transfer coefficient suggest that the velocity of the adsorbate transport
from bulk to solid phase is quite rapid.
Table 16: βL and Ss values for different adsorbates
Adsorbate βL (cm sec-1) Ss (cm-1)
Safranin 1.05 X 10-9 2.53 X 106
Copper 6.21 X 10-8 2.51X 106
Cadmium 7.22 X 10-8 5.02X 106
Lead 4.04 X 10-8 5.12X 106
74. Figure 38 : ln[Ct / C0 - 1/1+mk] vs. time plot for the mass transfer for (a) Safranin (b) Copper ( c) Cadmium
and (d) Lead at 298 K
(a) (b)
( c) (d)
75. CONCLUSIONS
The following conclusions can be drawn from this research work:
1. Characterization of fly ash and Zeolite material confirmed the rich mineral content and mesoporous texture.
2. Approximately 97.14% of Safranin, 95.7% of Copper, 89.7% of Lead, and 85.1% of Cadmium, were adsorbed
within the 3 hour, 4 hour, 2 hour and 1.5 hour of contact respectively after which there were a slow process.
3. The pH was found to be significant factor which affects the adsorption capacity of Safranin, Copper, Cadmium
and lead. The higher percentage adsorbate removal was found at pH of 9.0, 6.0, 5.0 and 5.0 respectively.
4. The higher percentage removal was found with optimum adsorbent dose of 0.1g (5 gL-1) in case of Safranin
and Copper while it was 0.2g (10gL-1) for Cadmium and Lead.
5. Adsorption capacity of zeolite for Copper was found to be decreasing with increase in temperature suggesting
that the adsorption process was exothermic in nature while in case of safranin, Cadmium and Lead the
adsorption increases with increase in temperature showing the process to be endothermic.
76. 6. The equilibrium adsorption data is better fitted by the Freundlich adsorption model than the Langmuir model
followed by DR and Temkin for Safranin and Lead while in case of Copper and Cadmium, Langmuir model is better
fitted than the Freundlich adsorption model followed by DR and Temkin and DR respectively.
7. Studies on the rate of uptake on zeolite under consideration indicate that the process is quite rapid and typically
24 to 38% of the ultimate adsorption occurs within the first hour of contact. This initial rapid adsorption
subsequently gives way to a very slow approach to equilibrium and the saturation is reached in 5 hours.
8. It is found that the rate of removal decreases with increasing amount of zeolite. For Safranin and Copper, the
optimum amount of fly ash is 5.0 gL-1, whereas the optimum amount of zeolite for Cadmium and Lead is 10.0 gL-1.
9. The linear nature of Kinetic Plots for Safranin, Copper, Cadmium and Lead at 250C show the applicability of the
Pseudo second order rate expression and indicates adsorption to be predominately chemo adsorption.
77. 10. The Bt versus Time plots of Safranin at concentration (≥5 ppm) shows the process is film-diffusion in nature. The
Bt versus time plot for Cu(II), Cd(II) and Pb(II) at higher concentrations (≥300 ppm) indicating the process to be
particle-diffusion but at lower concentrations (≥100 ppm) indicating a film-diffusion process.
11. The effective diffusion coefficient values lead to the inference that the channels in the Zeolite are wider than
those of hydrous oxides and clays.
The cost of synthesized zeolite was very low as compared to commercial zeolite available in the market as it was
prepared from coal fly ash-f waste material from thermal power station. Utilization of fly ash as zeolite for
adsorption will solve not only its disposal problems and environmental hazards, but also helps as potential
adsorbent for removal of pollutant from wastewaters. Results indicate that the developed low cost adsorbent
Zeolite material could be a promising solution to the removal of metals ions and dye from synthetic wastewater.
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81. List of Publications
1. Cadmium removal from aqueous solution by Na-P Zeolite Synthesised by caol fly ash Payal jain,
Suresh jain and M.K. Dwivedi. Juni Khyat, Volume no.10, Issue No. 06 , June 2020.
2. Modelling of Copper adsorption onto Na-P Zeolite synthesized from Coal Fly Ash Payal jain, Priyanka
Shrivastava , Richa Pathak and M.K. Dwivedi Research Journal of Chemistry and Environment volume
no.24, Issue No.8 August 2020.
3. Synthesis and characterization of Na-P zeolite from coal fly ash M.K. Dwivedi, Payal Jain, Chanchala
Alawa International Journal of Science Technology and Management Volume No.05, Issue No. 03,
March 2016 .
4. Adsorptive removal of phenol by coal fly ash equilibrium and thermodynamic studies M.K. Dwivedi,
Rashmi Agarwal, Pragati Sharma, Payal Jain . International Journal of Advanced Technology in
Engineering and Science Volume No.02, Issue No. 10, October 2014.
82. 5. Adsorptive Removal of Pb(II) from Aqueous Solution Using NaP Zeolite Synthesized From Coal Fly Ash.
Payal Jain, Priyanka Shrivastava, Vibha Malviya, Suresh Jain and M.K. Dwivedi .AIP Proceedings (Accepted)
2020 E-ISSN 1551-7616.
6. Thermodynamic and Kinetic Studies for the Removal of Safranin Dye from Aqueous Solution Using NaP
Zeolite Synthesized from Coal Fly Ash. Payal Jain, Priyanka Shrivastava, Vibha Malviya, Bijendra Rai and
M.K. Dwivedi. AIP Proceedings (Accepted).2020 E-ISSN 1551-7616.
7. Physicochemical analysis of water and soil samples collected from different sites of Pithampur Industrial
area Indore M.P. Richa Pathak ,Payal Jain, S.L. Garg and M.K. Dwivedi 2019 IJRAR Volume No.06 Issue No.
2 , October 2014.
8. FT-IR and ATR-FTIR studies of sludge (CETP) before and after adsorption of dyes from aqueous solution.
Vibha Malviya, M.K. Dwivedi, H. Bhatt, Arkadev Roy, Priyanka Shrivastava, Payal Jain. AIP Proceedings
(Accepted).2020 E-ISSN 1551-7616.
83. 9. Process Development for the Removal of Malachite Green Dye from wastewater using Sewage
Sludge (STP) as an Adsorbent. Priyanka Shrivastava M. K. Dwivedi, Vibha Malviya and Payal Jain. AIP
Proceedings (Accepted).2020 E-ISSN 1551-7616.
Thank you