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ABSTRACT: Nitrate–N and Fluoride concentrations were analyzed in shallow and unconfined ground water aquifers of Kanpur district along
the Ganges Alluvial Plain of Northern India. Kanpur district was divided into three zones namely, Bithore, Kanpur City and
Beyond Jajmau and sampling was carried out three seasons (summer, monsoon and winter). The data set consisted of the results
of water samples from around 99 India Mark II hand Pumps, which were analyzed for summer monsoon and winter seasons. In Bithore
zone, 19% of the samples exceeded the BIS (Bureau of India Standards) limit 10.2mg/l as nitrate–N and as high as 166mg/l
as nitrate–N was observed. 10% and 7% samples in Kanpur city and beyond Jajmau zone respectively, exceeded the BIS limit.
The Frequency distribution histogram of nitrate–N revealed a skewed (non-normal) distribution. Both point and non-point sources
contribute to the ground water contamination. Especially in Bithore zone, the point sources could be attributed to the animal
wastes derived from cows and buffaloes and non point sources could be due to the extensive agricultural activity prevalent
in that area. Fluoride concentration in most samples was within the BIS maximum permissible level of 1.5mg/l. No significant
seasonal variation in water quality parameters was observed.
Environmental Monitoring and Assessment 04/2012; 146(1):375-382. · 1.40 Impact Factor
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ABSTRACT: Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)-a biopolymeric waste obtained from marine industry.
Synthesis and characterization of the adsorbent using different spectral techniques like Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface analyzer have been carried out. Equilibrium studies have been carried out to optimize the dose rate, pH, and the reaction time. Parathion and methyl parathion removal were also evaluated by CuCH in the batch mode. Using gas chromatography-mass spectrometry (GC-MS) and FTIR studies suitable mechanism for adsorption has been suggested.
The particle size of the adsorbent ranged from 700 to 750 nm. The surface area was found to be 20 m(2) g(-1) with a pore volume of 0.11 cc g(-1). The maximum adsorption capacity of malathion by CuCH was found to be 322.6 ± 3.5 mg g(-1) at an optimum pH of 2.0. Presence of copper ions enhanced the adsorption capacity of the adsorbent. The reaction was found to follow pseudo second-order kinetics with a rate constant of 0.53 g mg(-1) min(-1). Evidence from FTIR indicated that copper ions form a dithionate complex with malathion during the adsorption stage. The adsorbent was found to remove malathion completely from spiked concentration of 2 mg l(-1) in the agricultural run-off samples. It was also found that CuCH removed other organophospurous pesticides like methyl parathion and parathion under prevailing conditions.
The results indicated that CuCH could be applied for the removal of organophosphorous pesticides.
Environmental Science and Pollution Research 01/2012; 19(6):2055-62. · 2.65 Impact Factor
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ABSTRACT: Evaluation of Chitosan zerovalent Iron Nanoparticle (CIN) towards arsenic removal is presented. Addition of chitosan enhances the stability of Fe(0) nano particle. Prepared adsorbent was characterized by FT-IR, SEM EDX, BET and XRD. It was found that, with an initial dose rate of 0.5 g L(-1), concentrations of As (III) and As (V) were reduced from 2 mg L(-1) to <5 μg L(-1) in less than 180 min and the adsorbent was found to be applicable in wide range of pH. Langmuir monolayer adsorption capacity was found to be 94±1.5 mg g(-1) and 119±2.6 mg g(-1) at pH 7 for As (III) and As (V) respectively. Major anions including sulfate, phosphate and silicate did not cause significant interference in the adsorption behavior of both arsenite and arsenate. The adsorbent was successfully recycled five times and applied to the removal of total inorganic arsenic from real life groundwater samples.
Chemosphere 11/2011; 86(2):150-5. · 3.21 Impact Factor
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ABSTRACT: The level of arsenic (As) contamination and the geochemical composition of groundwater in Shuklaganj area located on the banks of the Ganges Delta of Kanpur-Unnao district were elucidated. Samples (n = 59) were collected from both India Mark II hand pumps (depth, 30-33 m) and domestic hand pump tube wells (10-12 m) located within 5 km from the banks of Ganges. Samples were analyzed for various parameters, including total inorganic As, sulfate, nitrate, alkalinity, ammonia, and iron. Hydrochemistry of the groundwater aquifer was studied through the trilinear plots between monovalent and divalent cations and anions. In Indian mark II hand pumps, arsenic concentration ranged from below detection limit to 448 μg/L. Most of the samples contained both As(III) and As(V). The pH of the samples ranged from 7.1 to 8.2. Except for a few, most of the samples were reducing in nature as evident by their negative oxidation reduction potentials. A positive correlation for arsenic with iron, ammonia, and dissolved organic carbon shows the probability of biodegradation of organic matter and reductive dissolution of Fe oxyhydroxide processes to leach As in aquifers. For confirmation of the suggested arsenic mobilization mechanism, the presence and absence of sulfate-reducing bacteria and iron-reducing bacteria were also tested.
Environmental Monitoring and Assessment 09/2011; 184(8):4889-901. · 1.40 Impact Factor
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ABSTRACT: Removal of hexavalent chromium by xanthated chitosan was investigated in a packed bed up-flow column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 20 cm and flow rate of 5 mL min(-1), the metal-uptake capacity of xanthated chitosan and plain chitosan flakes for hexavalent chromium was found to be 202.5 and 130.12 mg g(-1) respectively. The bed depth service time (BDST) model was used to analyze the experimental data. The computed sorption capacity per unit bed volume (N(0)) was 4.6 ± 0.3 and 78.3 ± 2.9 g L(-1) for plain and xanthated flakes respectively at 10% breakthrough concentration. The rate constant (K(a)) was recorded as 0.0507 and 0.0194 L mg(-1)h(-1) for plain and xanthated chitosan respectively. In flow rate experiments, the results confirmed that the metal uptake capacity and the metal removal efficiency of plain and xanthated chitosan decreased with increasing flow rate. The Thomas model was used to fit the column sorption data at different flow rates and model constants were evaluated. The column was successfully applied for the removal of hexavalent chromium from electroplating wastewater. Five hundred bed volumes of electroplating wastewater were treated in column experiments using this adsorbent, reducing the concentrations of hexavalent chromium from 10 mg L(-1) to 0.1 mg L(-1).
Journal of hazardous materials 09/2010; 185(1):55-62. · 4.14 Impact Factor
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ABSTRACT: Decontamination of arsenic ions from aqueous media has been investigated using iron chitosan spacer granules (ICS) as an adsorbent. Drying of beads saturated with a spacer sucrose was considered as simple treatment, to prevent the restriction of polymer network and enhance sorption capacity. The novel sorbent was studied in up flow column experiments conducted at different flow rates, pH and bed depth to quantify the treatment performance. It was found that silicate was more inhibitory than phosphate, and the silicate in groundwater controlled the arsenic removal efficiency. The column regeneration studies were carried out for two sorption-desorption cycles using 0.1N NaOH as the eluant. TCLP leaching tests were conducted on the arsenic loaded adsorbent which revealed the containment of arsenic-laden sludge can be managed without adverse environmental impact. The developed procedure was successfully applied for the removal of both As(III) and As(V) from arsenic contaminated drinking water samples.
Bioresource technology 12/2009; 101(7):2173-9. · 4.25 Impact Factor
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ABSTRACT: A study on the removal of arsenic from real life groundwater using iron-chitosan composites is presented. Removal of arsenic(III) and arsenic(V) was studied through adsorption at pH 7.0 under equilibrium and dynamic conditions. The equilibrium data were fitted to Langmuir adsorption models and the various model parameters were evaluated. The monolayer adsorption capacity from the Langmuir model for iron chitosan flakes (ICF) (22.47+/-0.56 mg/g for As(V) and 16.15+/-0.32 mg/g for As(III)) was found to be considerably higher than that obtained for iron chitosan granules (ICB) (2.24+/-0.04 mg/g for As(V); 2.32+/-0.05 mg/g for As(III)). Anions including sulfate, phosphate and silicate at the levels present in groundwater did not cause serious interference in the adsorption behavior of arsenate/arsenite. The column regeneration studies were carried out for two sorption-desorption cycles for both As(III) and As(V) using ICF and ICB as sorbents. One hundred and forty-seven bed volumes of As(III) and 112 bed volumes of As(V) spiked groundwater were treated in column experiments using ICB, reducing arsenic concentration from 500 to <10 microg/l. The eluent used for the regeneration of the spent sorbent was 0.1M NaOH. The adsorbent was also successfully applied for the removal of total inorganic arsenic down to <10 microg/l from real life arsenic contaminated groundwater samples.
Water Research 09/2009; 43(15):3862-70. · 4.86 Impact Factor
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ABSTRACT: This paper highlights the mechanistic aspects of white rot fungus Coriolus versicolor as a complexing/reducing agent for chromium bioremediation. The chemical reduction of Cr(VI) to Cr(III) via the formation of Cr(VI) thio ester as an intermediate, is pH dependent and controls the overall chromium adsorption kinetics. The strong adsorption affinity of the biomass towards Cr(VI) anions was evaluated by the Freundlich and the Langmuir adsorption isotherms. The FTIR spectroscopic analysis suggested the involvement of amino, carboxylate, and thiol groups from fungal cell wall in chromium binding and reduction. The mechanism of the adsorption was preferential sequestration along with binding of the metal to the ligating groups present in the biomass followed by reduction to trivalent state. The results indicate step-wise progression of overall reaction dictated and modulated by structural and conformation effects in the biomass that lead to saturation, acceleration, and ultimate saturation kinetics effects.
Journal of hazardous materials 05/2009; 169(1-3):1074-80. · 4.14 Impact Factor
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ABSTRACT: Threat to human health worldwide due to the natural contamination of arsenic in ground waters has led to extensive studies on factors controlling the distribution of arsenic and conditions leading to arsenic mobilization in different arsenic contaminated areas. Another aspect of the arsenic crisis, especially in South Asia, is the degree of spatial variability of ground water arsenic concentrations. Thus it becomes necessary to study the source and the processes involved in arsenic mobilization into ground water under such conditions. An arsenic contaminated area namely, Ballia district of UP was chosen for this study. A set of 56 samples were collected from India Mark II hand pumps (30-33 m depth) thrice in a year namely pre-monsoon (April '07), monsoon (July '06) and winter seasons (December '06). Nine samples were also collected from deep bore well hand pumps (66-75 m) to study the difference in geochemistry with the shallow pumps. Various water quality parameters like As(III), As(V), sulfate, nitrate, phosphate, bicarbonate, ammonia, were determined. Arsenic concentrations ranged from 0 to 468 microg L(-1) in ground water collected from depths of 30-33 m. In the deeper wells (66-75 m), arsenic concentrations ranged from 12 to 20 microg L(-1). Most samples contained both As(III) and As(V) and the concentration of As(III) was generally equal/higher than As(V). Not much variation of arsenic concentration was observed when sampled in summer, monsoon and winter seasons. Correlation studies among various water quality parameters revealed that reductive dissolution of FeOOH was the most probable mechanism for release of arsenic.
Chemosphere 02/2009; 75(1):83-91. · 3.21 Impact Factor
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ABSTRACT: In this study two relatively new arsenic field kits, namely Wagtech Digital Arsenator (WFTK) and Chem-In Corp field test kit (CFTK) for arsenic were evaluated. The response of the two field test kits to known standards (Both As(III) and As(V)) is detailed. In addition around 157 arsenic-contaminated field samples obtained from various locations of Ballia and Kanpur districts, U.P., India were tested using the two kits and the results were compared with the laboratory-based colorimetric method (silver diethyldithiocarbamate method, SDDC). The concentration of arsenic in the 157 samples ranged from 0 to 468 microg l(-1). WFTK is seen to be suitable for measuring arsenic concentration <5-100 microg l(-1) using the digital meter. CFTK was not able to detect As(V) and its usage is cautioned in Uttar Pradesh where As(V) is seen to occur in appreciable concentrations. The Pearson's correlation between the silver diethyldithiocarbamate method and WFTK was found to be 0.87 and for the corresponding correlation with CFTK was 0.41 in the concentration range used in this study. Spearman's rank correlation coefficients comparing the WFTK and CFTK to laboratory measurements in the concentration range of 0-100 microg l(-1) were 0.95 (p<0.001) and 0.64 (p<0.001) respectively.
Science of The Total Environment 08/2008; 401(1-3):162-7. · 3.29 Impact Factor
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ABSTRACT: Decontamination of lead ions from aqueous media has been investigated using cross linked xanthated chitosan (CMC) as an adsorbent. Various physico-chemical parameters such as contact time, amount of adsorbent, concentration of adsorbate were optimized to simulate the best conditions which can be used to decontaminate lead from aqueous media using CMC as an adsorbent. The atomic absorption spectrometric technique was used to determine the distribution of lead. Maximum adsorption was observed at both pH 4 and 5. The adsorption data followed both Freundlich and Langmuir isotherms. Langmuir isotherm gave a saturated capacity of 322.6+/-1.2mg/g at pH 4. From the FTIR spectra analysis, it was concluded that xanthate and amino group participate in the adsorption process. The developed procedure was successfully applied for the removal of lead ions from real battery wastewater samples.
Bioresource Technology 06/2008; 99(18):9021-4. · 4.98 Impact Factor
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ABSTRACT: Chitosan was chemically modified by introducing xanthate group onto its backbone using carbondisulfide under alkaline conditions. The chemically modified chitosan flakes (CMC) was used as an adsorbent for the removal of cadmium ions from electroplating waste effluent under laboratory conditions. CMC was found to be far more efficient than the conventionally used adsorbent activated carbon. The maximum uptake of cadmium by CMC in batch studies was found to be 357.14 mg/g at an optimum pH of 8.0 whereas for plain chitosan flakes it was 85.47 mg/g. Since electroplating wastewater contains cyanide in appreciable concentrations, interference of cyanide ions in cadmium adsorption was found to be very significant. This problem could be easily overcome by using higher doses of CMC, however, activated carbon was not found to be effective even at higher doses. Due to the high formation constant of cadmium with xanthate and adsorption was carried out at pH 8, cations like Pb(II), Cu(II), Ni(II) and Zn(II) did not interfere in the adsorption. Dynamics of the sorption process were studied and the values of rate constant of adsorption were calculated. Desorption of the bound cadmium from CMC was accomplished with 0.01 N H(2)SO(4). The data from regeneration efficiencies for 10 cycles evidenced the reusability of CMC in the treatment of cadmium-laden wastewater.
Journal of Hazardous Materials 09/2007; 148(1-2):353-9. · 4.17 Impact Factor
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ABSTRACT: Suitability of a novel cross linked, chemically modified chitosan as highly efficient adsorbent for the recovery of toxic chromium(VI) was studied. After cross linking with glutaraldehyde, xanthate group was grafted onto the back bone of chitosan. Sorption was found to be both pH and concentration dependent, with pH 3 being the optimum value. Both, chemically modified beads (CMCB) and flakes (CMCF) followed a pseudo-second-order kinetics with a rate constant of 2.037 and 4.639 g/mg/min, respectively. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 625 mg/g and 256.4 mg/g and for CMCF and CMCB respectively. Desorption studies revealed the reusability of the sorbent for at least 10 cycles without any significant change in adsorption capacities.
Bioresource Technology 01/2007; 97(18):2377-82. · 4.98 Impact Factor
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ABSTRACT: Indicators to distinguish between fecal coliforms of human and animal origin were investigated in water from storm sewer outfalls to a coastal lake during wet and dry weather. The ratio of fecal coliform relative to fecal streptococci count was used as the microbiological indicator. Concentrations of human-activities originated caffeine, anionic surfactant, fluoride, and fluorescence whitening agent (FWA) were used as chemical indicators. The ratio of fecal coliform to fecal streptococci ranged from 0.2 to 3.0, during wet weather making it difficult to interpret the origin of fecal pollution. However, concentrations of caffeine, anionic surfactant, fluoride, and FWA in storm water outflow during wet weather were much higher than those in the lake water during dry weather, indicating the presence of human waste at storm water outfall. Strong correlation between fecal coliform counts and chemical parameter values further indicated the human contribution to the fecal coliform count. In addition, a strong correlation among the chemical parameters suggested that only one of them is needed as chemical tracer to detect the presence of human input.
Environment International 11/2005; 31(8):1133-40. · 5.30 Impact Factor
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ABSTRACT: A survey undertaken in Kanpur, northern India, has shown the presence of high concentrations of both organochlorine and organophosphorous pesticides in the surface and ground water samples. Liquid-liquid extraction followed by GC-ECD was used for the determination of these compounds. Among the various pesticides analyzed, high concentrations of gamma-HCH (0.259 microg/l) and malathion (2.618 microg/l) were detected in the surface water samples collected from the River Ganges in Kanpur. In the ground water samples collected from the various hand pumps located in agricultural and industrial areas, apart from gamma-HCH and malathion, dieldrin was also detected. The maximum concentration values of gamma-HCH, malathion and dieldrin were 0.900, 29.835 and 16.227 microg/l, respectively. Especially, the concentration of malathion was found to be much higher than the EC water quality standards in the ground water samples from industrial area posing a high risk to the common people. Pesticides like DDE, DDT, aldrin, ethion, methyl parathion and endosulfan were not detected in both the surface and ground water samples.
Environment International 02/2005; 31(1):113-20. · 5.30 Impact Factor
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ABSTRACT: A novel xanthated chitosan derivative was prepared by the chemical reaction of CS2 under alkaline conditions. Spectroscopic studies like FTIR, 13C NMR, TGA and XRD, SEM, and EPR were used for its characterisation. The chemically modified chitosan (CMC) was evaluated for its adsorption properties for Cr(VI). For a 100 mg/L solution of Cr(VI), the uptake of Cr(VI) by CMC at pH 3, was found to be much enhanced (71 mg/L) compared to the control chitosan (49 mg/L). The CMC can be a potential adsorbent for tannery wastewater treatment.
Carbohydrate Polymers.
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ABSTRACT: Removal of cadmium by xanthated chitosan was investigated in a packed bed up-flow column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 9 cm and flow rate of 3 ml min−1, the metal-uptake capacity of xanthated chitosan and plain chitosan flakes for cadmium was found to be 132.3 ± 1.5 and 40.1 ± 0.5 mg g−1 respectively. The bed depth service time (BDST) model was used to analyze the experimental data. The computed sorption capacity per unit bed volume (N0) was 2.19 and 14.6 g l−1 for plain and xanthated flakes respectively. The rate constant (Ka) was recorded as 0.5514 and 0.0418 l mg−1 h−1 for plain and xanthated chitosan respectively. In flow rate experiments, the results confirmed that the metal-uptake capacity and the metal removal efficiency of plain and xanthated chitosan decreased with increasing flow rate. The Thomas model was used to fit the column sorption data at different flow rates and model constants were evaluated. The column regeneration studies were carried out for two sorption–desorption cycles. The eluant used for the regeneration of the sorbent was 0.01 N H2SO4. A decreased breakthrough time and an increased exhaustion time were observed as the regeneration cycle progressed, which also resulted in a broadened mass transfer zone. The column was successfully applied for the removal of cadmium from electroplating wastewater. Three hundred sixty-seven bed volumes of electroplating wastewater were treated in column experiments using this adsorbent, reducing the concentrations of Cd(II) from 10 to 0.1 mg l−1.
Separation and Purification Technology.
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ABSTRACT: In this study, we have prepared iron-doped activated micro/nano carbon particles as efficient adsorbents for arsenic removal. Starting with phenolic resin monomers, polymeric spherical beads of size ∼0.2–1 mm were first synthesized by suspension polymerization. Iron (Fe) was incorporated in an intermediate step during polymerization. The internal porous structure was developed in the Fe-doped polymeric beads by carbonization followed by physical activation using steam. Subsequent to activation, beads were milled to prepare the micro/nano particles in the size range of 100–500 nm. In an alternate route to preparing the adsorbents, the synthesized polymeric beads were first milled and then carbonized and activated. The absorbent particles thus prepared were applied in the removal of arsenic (III and V) present at low concentration levels (<20 mg/L) in water. The method in which milling was performed first produced a superior adsorbent. For both the ions, the equilibrium loading (∼3–15 mg/g) in the adsorbate were found to be comparable to the adsorbates reported in literature. The simple and up-scalable methodology developed in this study has the potential for the preparation of a wide variety of similar metal impregnated porous (polymeric precursor based) adsorbents/catalysts in other environmental remediation applications.
Chemical Engineering Science 65(11):3591-3601. · 2.43 Impact Factor
