Personal Research Database

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 1145.pdf

Abstract: Surfactant-based technologies are promising remediation alternatives. The information on sorption and desorption kinetics of surfactants on soils is important in the successful application of surfactant-based technologies. In this study, the sorption and desorption rates of nonionic surfactant TX-100 and cationic DPC were correlated to the surfactant concentration, soil organic matters (SOM), and soil cation exchange capacity (CEC). The results indicated that at higher initial surfactant concentrations, sorption rates of surfactants increased linearly with SOM and soil CEC for TX-100 and DPC, respectively. The sorption rates and initial surfactant concentrations followed the first order relation for TX-100 and second order for DPC. A linear relationship between the sorption rates of surfactants and soil characteristics was developed., The desorption rates of TX-100 and DPC increased linearly with the increased surfactant levels sorbed on soils but were irrelevant to soil characteristics and the contact time of surfactant sorption. The rate of surfactant desorption was similar as the amount of surfactants sorbed on soils was in the same range. The cationic DPC sorbed and desorbed at two orders of magnitude faster than the nonionic TX-100, suggesting that both sorption and desorption have to be considered in the remediation process.

Keywords: Soils, Surfactant, Sorption, Desorption, Rates, Nonionic Surfactants, Water, Phenanthrene, Organoclays, Clay

Huang, H.H., Lu, M.C., Chen, J.N. and Lee, C.T. (2003), Influence of surface modification on catalytic activity of activated carbon toward decomposition of hydrogen peroxide and 2-chlorophenol. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 38 (7), 1233-1246.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 1233.pdf

Abstract: The objective of this research was to investigate the influence of the activated carbons modified by chemical treatment on the surface catalyzed loss of H₂O₂ and 2-CP. The characteristics of the modified activated carbons were examined by several techniques including nitrogen adsorption, SEM, and EDS. The H₂O₂ decomposition rate would be suppressed significantly either by the change of surface properties modified with chemical treatment or the reduction of active sites occupied with the adsorption of 2-CP. In addition, the H₂O₂ decomposition rate with activated carbons within a specific time can be described by a second-order kinetic expression with respect to the concentration of GAC and H₂O₂ in the absence or presence of 2-CP. The catalytic activities of the three activated carbons toward 2-CP reduction followed the inverse sequence of those toward H₂O₂ loss, implying that acidic surface functional group could retard the H₂O₂ loss and reduce the effect of surface scavenging resulting in increasing the reduction efficiency of 2-CP. By the detection of chloride ions in reaction mixture, it can be demonstrated that the reduction of 2-CP was not only attributed to the advanced adsorption but also the oxidation of the 2-CP with effective radicals. The real oxidation efficiency of 2-CP for the activated carbon modified with hot nitric acid was observed between 0.04 and 0.01 (mol/mol), offering a comparable efficiency to that of the other oxidation system using metal oxide as catalyst.

Keywords: Granular Activated Carbon, Hydrogen Peroxide, 2-Chlorophenol, Heterogeneous Catalysis, Oxidation, Degradation, Adsorption, Quinoline, Phenols, Oxides, Impact, H₂O₂

Dutta, K., Bhattacharjee, S., Chaudhuri, B. and Mukhopadhyay, S. (2003), Oxidative degradation of malachite green by Fenton generated hydroxyl radicals in aqueous acidic media. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 38 (7), 1311-1326.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 1311.pdf

Abstract: Fenton-generated hydroxyl radicals removes the color of the malachite green, a basic dye with triphenylmethane group, almost (similar to 98%) completely in weakly acidic aqueous media possibly through oxidative degradation pathways as evidenced from a remarkable lowering in the COD value of the product mixture in comparison to the title dye under identical conditions and almost full quenching of the reaction in presence of hydroxyl radical scavengers. The dye can most effectively be degraded at dye: Fe²⁺ : H₂O₂ molar ratio of 1: 3.3: 81.7 for 1.08×10^-5 moldm^-3 dye at pH 2.5-2.8 and at 299K. The rate law of the dye degradation process appears to be: -d[dye]/dt=k[dye] [Fe²⁺](0.79) [H₂O₂](0.12), where k= (33±5) (dm³ mol^-1)0.91 s^-1 at 299K. Salts like NaCl or NaBr retard the degradation rate markedly whereas SO₄^2- or ClO₄^- are rather innocent. In presence of Cl-, the radical reaction:

ClOH^-. + Fe²⁺ --> Cl^- + HO^- + Fe³⁺

may account for the gross lowering of degradation rate. The results may be helpful for designing the treatment plants of wastewater containing dyes with triphenylmethane group.

Keywords: Fenton-Like Oxidation, Degradation, Malachite Green, Hydroxyl Radical, Wastewater Chemical Oxidation, Hydrogen-Peroxide, Waste-Water, Contaminated Soils, Rate Constants, Reactive Dyes, Superoxide Ion, Reagent, Kinetics, Decolorization

? Park, J.H., Choi, E. and Gil, K.L. (2003), Removal of reactive dye using UV/TiO₂ in circular type reactor. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 38 (7), 1389-1399.

Full Text: 2003\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 1389.pdf

Abstract: Photocatalytic degradation of reactive dye, Red 120, was carried out on TiO₂ particles as photocatalyst under UV irradiation. In this experiment, comparison on the removal of reactive dye by photolysis using UV light alone, photocatalyst adsorption using TiO₂ alone and photocatalysis using UV light with photocatalysts as well as the effect of experimental parameters such as the number of column employed, intensity of the light, pH and TiO₂ dosage affecting the reaction efficiency of photocatalytic degradation of reactive dye in circular type reactor was examined. The results of this indicate that with both UV light illumination and TiO₂ present, reactive dye was more effectively eliminated than with either UV or TiO₂ alone. Photocatalytic degradation of reactive dye increased linearly with increasing UV light intensity. However, over 18 mW cm^-2 of UV light intensity, the efficiency reached a plateau. The photocatalytic degradation rate was greater in acid media than in alkaline media. Photocatalytic removal efficiency of reactive dye increased with increasing TiO₂, dosage. However, over 1.5 g L^-1 of TiO₂ dosage, the efficiency reached a plateau.

Keywords: Adsorption, Degradation, Dispersions, Dye, Particles, Photocatalytic, Photocatalytic Decolorization, Photolysis, Pollutants, Powdered Semiconductor TiO₂, Reactive Dye, Removal, TiO₂, UV Light, Visible-Light Irradiation

Armağan, B., Ozdemir, O., Turan, M. and Çelik, M.S. (2003), Clay mineral batch process for color removal of textile wastewaters. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 38 (10), 2251-2258.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 2251.pdf

Abstract: Textile industry effluents exhibit large amounts of dye chemicals, which create severe water pollution. It is therefore important to reduce the dye concentration in the wastewater before discharging into the environment. In this study, the ability of sepiolite to uptake different reactive dyes is investigated. The dyes used in the experiments are Everzol Black B, Everzol Yellow 3RS H/C, and Everzol Red 3BS. A number of parameters on adsorption has been investigated in order to establish the adsorption pattern of sepiolite. The effect of conditioning time, solid/liquid ratio, pH, temperature, and dye concentrations on adsorption are studied. Adsorption isotherms for different reactive dyes have been obtained using both natural and modified sepiolites. The maximum capacity of natural sepiolite for the reactive dyes occurs at around 0.1-1 mg/g. Therefore, the natural sepiolite appears to have a little capacity for reactive dyes. The zeta potential profiles of natural and modified sepiolites against pH are also examined. The modified sepiolite exhibited ten times higher performance than the natural sepiolite.

Keywords: Color Removal, Modified Sepiolite, Reactive Dyes, Sepiolite, Textile Wastewater, Activated Carbon, Adsorption Mechanism, Aqueous-Solutions, Reactive Dyes, Sepiolite, Amines, Water, Ammonia

Chiou, M.S., Kuo, W.S. and Li, H.Y. (2003), Removal of reactive dye from wastewater by adsorption using ECH cross-linked chitosan beads as medium. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 38 (11), 2621-2631.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng38, 2621.pdf

Abstract: The feasibility of the removal of reactive dye from wastewater using a novel adsorbent, ECH cross-linked chitosan beads, as medium was examined. The effect of the pH and the initial concentration of the dye (RR222) solution on the adsorption capacity of the ECH cross-linked chitosan beads were also investigated. It was found that the initial dye concentration and the pH of the solution significantly affected the adsorption capacity. An increase in initial dye concentration results in the increase of adsorption capacity while an acidic pH was found to be favorable for the adsorption of dye. It was also found that the equilibrium adsorption of RR222 could be adequately described by using the Langmuir model (r² greater than or equal to 0.999). Moreover, results showed that the adsorption rate of RR222 onto ECH cross-linked chitosan beads could be described by using the second-order kinetic model, suggesting that chemical sorption instead of mass transfer was the rate-limiting step for the adsorption process. The maximum monolayer adsorption capacity obtained from the Langmuir model was extremely high as compared to the data reported in literature; 2252 g/kg at 30degreesC with a pH of 3.0. Therefore, ECH cross-linked chitosan beads could be a feasible medium for the removal of reactive dye from wastewater and potentially an alternative for the decolorization of wastewater.

Keywords: Adsorption Capacity, Reactive Dye, RR222, ECH Cross-Linked Chitosan Beads, Color Removal, Acid Dye, Equilibrium, Biosorption

Kundu, S., Pal, A., Mandal, M., Ghosh, S.K., Panigrahi, S. and Pal, T. (2004), Hardened paste of Portland cement: A new low-cost adsorbent for the removal of arsenic from water. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (1), 185-202.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 185.pdf

Abstract: Portland cement has been used as a low-cost adsorbent for the removal of arsenic from the water environment. In the batch experiments conducted at an initial concentration of 0.2 ppm of arsenate, it was found that arsenate could be removed up to 95%. Kinetic profiles were developed for various conditions. Effect of adsorbent dose, effects of common ions such as Ca²⁺, Mg²⁺, Fe³⁺/Fe²⁺, Cl^-, SO₄^2-, NO₃^-, PO₄^3-, and the effect of pH was studied. Adsorption isotherm studies were performed and it was observed that the Freundlich isotherm was followed with a better correlation than the Langmuir isotherm. Arsenite could also be removed up to similar to88% using the same material. A new detection method for arsenate/arsenite was developed for routine analysis of arsenic and used during the entire study.

Keywords: Portland Cement, Adsorption, Arsenate Removal, Hydrous Ferric-Oxide, Of-Use Treatment, Drinking-Water, Adsorption, Coagulation, Groundwater, Environment, Samples, Iron

Wang, L., Chua, H., Sin, S.N., Zhou, Q., Ren, D.M. and Li, Z.L. (2004), A combined bioprocess for integrated removal of copper and organic pollutant from copper-containing municipal wastewater. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (1), 223-235.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 233.pdf

Abstract: Heavy metal-containing wastewater is difficult to treat by most of the bioprocess due to its toxicity to microorganism in activated sludge In this study, a combined bioprocess consisting of biosorption section that contained magnetite immobilized Pseudomonas putida 5-x cell as biosorbent followed by sequence batch reactor (SBR) was developed to treat Cu²⁺- containing municipal wastewater. The production techniques of Pseudomonas pulida 5-x cell as biosorbent, such as optimal cell harvest period and cell pretreatment techniques were studied. Experimental results showed, considering both cell biomass and cell adsorption capacity to Cu²⁺, 36h is the optimal harvest period in the course of culturing Pseudomonas putida 5-x cells as biosorbent, and 0.1-0.3mol L^-1 HCl is an optimal cell pretreating eluant to improve Cu²⁺ adsorption capacity. The performances of the combined bioprocess for treating Cu²⁺ containing wastewater were assessed. Experimental results showed that after treatment by biosorption, the Cu²⁺ level in wastewater was reduced to level that did not inhibit COD removal efficiency of subsequent SBR activated sludge process, although it still affected the COD adsorption capacity of activated sludge. In terms of COD removal, the biosorption section was efficient for reducing Cu²⁺ concentration to provide biodegradable wastewater for subsequent SBR activated sludge process.

Keywords: Adsorption, Biomass, Biosorption, Cell Pretreatment, Chromium, COD Adsorption Capacity (CAC), Cod Removal, Cu²⁺ Adsorption, Heavy-Metals, Ions, Nickel, Pseudomonas putida, Pseudomonas-Putida, Ramigera

Wu, C.H., Lin, C.F. and Horng, P.Y. (2004), Adsorption of copper and lead, ions onto regenerated sludge from a water treatment plant. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (1), 237-252.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 237.pdf

Abstract: In this study, water treatment sludges were sintered under various experimental conditions to generate Al-containing adsorbents. The adsorption of Cu²⁺ and Pb²⁺ onto sintered oxide was examined and sorption results were further modeled using a surface complex model. The specific surface area of the sintered adsorbent was substantially reduced from 30m²/g (dried sludge) to 2 m²/g (sinter sludge). The pH-adsorption-edges of both Cu²⁺ and Pb²⁺ were shifted towards a higher pH than the edges of the unsintered adsorbent, revealing reduced affinity of the sintered adsorbent for metal ions. Metal leaching was measured by the TCLP procedure, and the results indicated that the amount of metal leaching by the sintered adsorbent was negligible. The effect of background electrolytes on Cu²⁺ and Pb²⁺ sorption was negligible. Triple-layer model (TLM) simulation revealed that Cu²⁺ and Pb²⁺ sorption on sintered adsorbent involves inner-sphere interactions and the dominant surface metal species are monodentates of Me²⁺ and MeOH⁺. The intrinsic adsorption constants of Cu²⁺ and Ph²⁺ on dried sludge, adsorbent sintered at 1000degreesC, and adsorbent sintered at 1100degreesC were also examined.

Keywords: Cu²⁺, Pb²⁺, Water Treatment Sludge, Sinter, Adsorption, Surface Complex Model, Tlm, Modeling Competitive Adsorption, Leaching Tests, Heavy-Metals, Fly-Ash, Waste, Molybdate, Sorption, Oxides, Phosphate, Kaolinite

Nassar, M.M., Ewida, K.T., Ebrahiem, E.E., Magdy, Y.H. and Mheaedi, M.H. (2004), Adsorption of iron and manganese using low cost materials as adsorbents. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (2), 421-434.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 421.pdf

Abstract: Removal of toxic metals (iron and manganese) ions from aqueous solution by adsorption was studied. Batch tests were used to study the removal of each metal either as a single component or both metals as multicomponent. The adsorbents used are low cost materials namely; palm fruit bunch and maize cobs. The adsorption isotherms proved the favor ability of the adsorbent used. Removal of iron ion by adsorption on palm fruit bunch and maize cobs was in the range of 80-57%, and for magnesium ion in the range of 79-50% for initial concentration ranged between 1 and 10 ppm. In case of mixture of both metals, removal of iron from the mixture was in the range 79-54% and for magnesium was in range of 76-54%.

Keywords: Toxic Metals, Adsorption, Palm Fruit Bunch, Maize Cobs, Iron, Manganese, Palm-Fruit Bunch, Activated Carbon, Aqueous-Solutions, Dyes, Equilibrium, Particles, Kinetics, Removal, Ions

Fadali, O.A., Magdy, Y.H., Daifullah, A.A.M., Ebrahiem, E.E. and Nassar, M.M. (2004), Removal of chromium from tannery effluents by adsorption. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (2), 465-472.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 465.pdf

Abstract: Tannery effluent is characterized not only by heavy loads but also with toxic heavy metals especially chromium ions. Chromium is considered an important source of contamination due to large volume of exhaust liquid discharged and solid sludge produced. Details on adsorption studies were carried out using synthetic chromium salts (chromium chloride) as adsorbate, and cement kiln dust (a waste from white cement industry) as adsorbent. Equilibrium isotherms have been determined for the adsorption of chromium ions on cement kiln dust. Kinetic study provided that the adsorption process is diffusion controlled. The experimental results have been fitted using Freundlich, Langmuir, and Redlich Peterson isotherms. The maximum adsorption capacity of cement kiln dust was found to be 33 mg/g. Industrial tannery effluent (22-mg/L chromium and COD 952 mg/L) was also treated by cement dust. The treated effluent (using 20 g cement dust per 1 L) contains only 0.6 mg/L chromium and COD 200 mg/L.

Keywords: Adsorption Isotherms, Cement Kiln Dust, Effluent Treatment, Tannery Waste, Aqueous-Solutions

Zaidi, S. and Musarrat, J. (2004), Characterization and nickel sorption kinetics of a new metal hyper-accumulator Bacillus sp. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (3), 681-691.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 681.pdf

Abstract: The heavy metal-resistant bacterial strain SJ-101 has been isolated from fly ash contaminated soil. Based on the morphological and biochemical characteristics, the isolate SJ-101 was presumptively identified as Bacillus sp. The adsorption isotherms revealed the absolute adsorption capacity (Qdegrees) of 244 mg Ni g^-1 dry cell I mass vis-A-vis 161 mgNig^-1 synthetic resin (Amberlite IR-120). The higher relative adsorption capacity (K-F) of 7.37, and the intensity of adsorption (1/n) of 0.58 with dry cell biomass suggested higher affinity of Bacillus cells towards nickel ions, The data conform to the Langmuir adsorption model relatively better than the Freundlich model. The thermodynamic parameters indicated the feasibility, endothermic, and, interactive nature of nickel, adsorption process on the cell surface, Higher Ni tolerance and sorption capacity of Bacillus sp. SJ-101, explicitly signifies its implications in Ni bioremediation process.

Keywords: Heavy Metals, Bioaccumulation, Biosorption, Bacillus sp., Metal Toxicity, Xylosoxidans 31A, Cell-Wall, Resistance, Subtilis, Mercury, Cobalt, Microorganisms, Biosorption, Induction, Toxicity

Satyanarayan, S., Venerkar, A.P. and Ramakant (2004), Organic removals from highly proteinous wastewater from soya milk and tofu manufacturing plant. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (3), 759-771.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 759.pdf

Abstract: Combined, wastewater from soya milk and tofu manufacturing industry was treated by physico-chemical method using conventional coagulants such as lime, alum, ferric chloride, and ferrous sulphate in combination with synthetic cationic polyelectrolyte. The wastewater samples were analyzed as per the Standard Methods and the experiments were carried out using Jar test apparatus (Phipps & Birds). The ferric chloride in combination with synthetic cationic polymer (Oxyfloc-FL-11) in the ratio of 250: 20 mg L^-1 resulted in very good removals of COD, BOD, and SS of 75.4, 79.8, and 96.0% respectively with complete removal of odor, color and turbidity.

Keywords: Soyabean Wastewater, Tofu, Coagulants, Polyelectrolyte, Cationic

Armağan, B., Turan, M., Özdemir, O. and Çelik, M.S. (2004), Color removal of reactive dyes from water by clinoptilolite. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (5), 1251-1261.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 1251.pdf

Abstract: The adsorption of reactive dyes on Gordes (Turkey) clinoptilolite was investigated by a series of batch and column adsorption experiments. Three reactive dyes (Everzol Black, Everzol Red. Everzol Yellow) were used in laboratory studies. Synthetic wastewaters were used and the ability of natural zeolite (clinoptilolite) and their modified form were examined. The adsorption results, in batch and column reactor, indicate that natural zeolite have limited adsorption capacities of the reactive dyes but are substantially improved upon modifying their surfaces with quaternary amines (HTAB). The degree of hydrophilicity is found to play an important role in the uptake of reactive dyes.

Keywords: Activated Carbon, Adsorption, Adsorption, Aqueous-Solutions, Clinoptilolite, Color Removal, Column Operations, Dyes, Equilibrium Uptake, External Mass-Transfer, Fly-Ash, Heavy-Metals, Htab, Reactive Dyes, Removal, Sorption Dynamics, Textile Industry Wastewater, Waste-Water, Zeolite

? Turan, M., Armagan, B., Ozdemir, O. and Celik, M.S. (2004), Mesoporous mineral columns for color removal from aqueous solutions. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (8), 2221-2228.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 2221.pdf

Abstract: The removal efficiency of natural minerals (e.g., zeolite and sepiolite) from aqueous solutions of azo dyes was investigated. The adsorption of three types of reactive dyes, Black, Red, and Yellow dissolved in distilled and/or deionized water on zeolite and sepiolite have been performed using column adsorption experiments. Distilled water containing 50 mg/L dyestuff was used to identify the ability of natural mesoporous minerals and their modified forms. The adsorption results indicate that both natural sepiolite and zeolite have limited adsorption capacities of the reactive dyes but are substantially improved upon modifying their surfaces with quaternary amines (HTAB). The removal of Yellow dye showed an excellent performance in sepiolite column compared to that in zeolite column.

Keywords: Adsorption, Adsorption, Amines, Ammonia, Carbon, Clinoptilolite, Color Removal, Dye, Dyes, Fixed Bed, Green, Htab, Reactive Dyes, Removal, Sepiolite, Sepiolite, Zeolite, Zeolites

? Orescanin, V., Mikelic, L., Lulic, S., Nad, K., Mikulic, N., Rubcic, M. and Pavlovic, G. (2004), Purification of electroplating wastewaters utilizing waste by-product ferrous sulfate and wood fly ash. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (9), 2437-2446.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 2437.pdf

Abstract: A new procedure for electroplating wastewater treatment using waste by-product (ferrous-sulfate) and waste (wood fly ash) is presented. Ferrous-sulfate was employed for Cr(VI) reduction whereas neutralization and heavy metal removal from electroplating wastewaters was performed using wood fly ash. Heavy metal removal efficiency varied from 97.5% for Cu to 99.973% for Zn. Satisfying results can be achieved already at the pH 8. The method is suitable for the purposes of wastewater treatment and disposal in compliance with environmental laws. Furthermore, it is technically simple, cost-efficient and requires less space compared to the classical methodology. According to the composition of its water extractable fraction remaining waste ash could be safely deposited on domestic waste repositories.

Keywords: Chromate, Coagulant Production, Electroplating Wastewater, Ferrous Sulfate, Heavy Metals, Heavy-Metals, Ion-Exchange, Iron, Recovery, Red Mud, Reduction, Removal, Water, Wood Fly Ash

? Kang, H.J., An, K.G. and Kim, D.S. (2004), Utilization of steel slag as an adsorbent of ionic lead in wastewater. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 39 (11-12), 3015-3028.

Full Text: 2004\J Env Sci Hea Par A-Tox Haz Sub Env Eng39, 3015.pdf

Abstract: The feasibility of using slag, a waste from steel-making industry, as an adsorbent for ionic lead in wastewater was studied. Kinetic and equilibrium aspects of Pb2+ adsorption on the slag were investigated along with the effects of temperature and pH. Additionally, adsorption change at different ionic strength and desorption characteristics were also addressed. We identified that the adsorption kinetics of Pb2+ on the slag follows a first order reaction that can be modeled by Freundlich adsorption isotherm. It was also found that equilibrium adsorption of Pb2+ decreases with pH, which may be associated with the change of electrokinetic potential of slag as a function of pH. As temperature increases the adsorption capacity rises, and the data can be best fitted using van’t Hoff equation. Ionic strength was found to negatively affect the adsorbability of Pb2+. Most of the adsorbed Pb2+ could be desorbed rapidly by a complexing agent, such as EDTA, which may suggest the feasibility of recycling of slag as an adsorbent for Pb2+.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Kinetics, Desorption, Dynamics, EDTA, Equilibrium, Feasibility, Industry, Ionic Lead, Isotherm, Kinetic, Kinetics, Lead, pH, Removal, Steel Slag, Strength, Wastewater

? Adak, A., Bandyopadhyay, M. and Pal, A. (2005), Adsorption of anionic surfactant on alumina and reuse of the surfactant-modified alumina for the removal of crystal violet from aquatic environment. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 40 (1), 167-182.

Full Text: 2005\J Env Sci Hea Par A-Tox Haz Sub Env Eng40, 167.pdf

Abstract: The adsorption characteristics of sodium dodecyl sulfate (SDS), an anionic surfactant on neutral alumina were studied in detail. Alumina was found to be an efficient adsorbent for SDS and could be used for the removal of SDS from its highly concentrated (several thousand ppm) solution. The equilibrium time found was 2 h. Though the removal efficiency was low (similar to65%) at neutral pH, but in slightly acidic condition and in the presence of NaCl the efficiency could be increased dramatically (up to >98%). The adsorption isotherm study showed,distinct four regions. The effects of various other parameters such as adsorbent dose, time, and the presence of different ions (Cl^-, NO₃^- SO₄^2-, and Fe³⁺), and nonionic surfactant on the SDS adsorption were also studied. It Was 4 observed that the adsorption capacity was increased due to the presence of these ions in general. After the adsorption of SDS on alumina, the surfactant-modified alumina (SMA) was used for the removal of crystal violet (CV), a well-known cationic dye from aquatic environment. The kinetic studies showed that 1 h shaking time was sufficient to achieve the equilibrium. The removal of CV followed the second order kinetics. Studies were conducted to see the effects of adsorbent dose and initial CV concentration on the removal of CV using SMA. The pH was maintained at 6.7  0.1. SMA was found to be very efficient, and similar to 99% efficiency could be achieved under optimised conditions for the removal of CV when present even at a high concentration (200 ppm). To test whether the removal of CV was possible from real water using SMA, the adsorption study was conducted using CV spiked samples using distilled water, tap water, and synthetically prepared wastewater. It was interesting to note that the removal efficiency was even better for tap water and much better for wastewater when compared to that using distilled water. Desorption of both SDS and CV from the SMA surface was possible using 1 M sodium hydroxide solutions.

Keywords: Adsolubilization, Adsolubilization, Adsorption, Adsorption Isotherm, Alumina, Anionic Surfactant, Aquatic, Aquatic Environment, Capacity, Concentration, Condition, Crystal Violet, CV, Dye, Efficiency, Environment, Equilibrium, Fenton Oxidation, Interface, Isotherm, Kinetic, Kinetics, Low-Cost Adsorbent, NO₃, Parameters, pH, Removal, Removal Efficiency, Reuse, Silica, Sodium, Sodium Dodecyl Sulfate, Sodium Hydroxide, Sulfate, Surface, Surfactant, Surfactant-Modified Alumina, Textile Waste-Water, Wastewater, Water

? Kundu, S. and Gupta, A.K. (2005), Sorption kinetics of As(V) with iron-oxide-coated cement - A new adsorbent and its application in the removal of arsenic from real-life groundwater samples. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 40 (12), 2227-2246.

Full Text: 2005\J Env Sci Hea Par A-Tox Haz Sub Env Eng40, 2227.pdf

Abstract: In the search of alternative adsorbents for the removal of arsenic, a new adsorbent (iron-oxide coated cement) was examined under various conditions to evaluate its suitability in removing As(V). A removal of more than 99% was obtained within 2 h for an initial As(V) concentration of 1 mg/L. Mnetic studies showed a removal which became somewhat constant after 2 h. Thorough investigations to understand the mechanism of solute adsorption onto the new sorbent with the help of four kinetic models, viz. similar to first-order reversible kinetics model, pseudo-first-order kinetic model, second-order kinetic model, and pseudo-second-order kinetic model showed that the sorption kinetics is consistent with the pseudo-second-order model from which it can be inferred that the mechanism of adsorption is chemical interaction or chemisorption. The equilibrium data followed the Langmuir isotherm at low concentrations of As(V) (: 4 mg/L), but followed the Freundlich isotherm over a wide range of concentrations (0.5-10 mg/L) which can be due to solid solution precipitation. Studies on the effect of pH on As(V) removal revealed somewhat constant (similar to 95%) As(V) removal over a wide pH range of 4-10. The efficiency of this adsorbent was also checked for the removal of arsenic from three real ground water samples containing both As(III) and As(V) with total arsenic in the range of 0.33-1.2 mg/L. The total arsenic removal was 71%, 87% and 75% for the samples containing 0.33, 0.88 and 1.2 mg/L total arsenic, respectively at the same adsorbent dose of 3 g/L. However, increasing the adsorbent dose will enhance removal capacity. Investigations of these real samples with the four kinetic models revealed most reliable fit with the pseudo-second order model. However, good fit was also obtained with the other three models. Values of the diffusion coefficients calculated from the first order kinetics data, indicated that, film diffusion is the rate limiting step for each of the three real life groundwater samples.

Keywords: Arsenic Removal, Adsorption, Iron Oxide Coated Cement, Pseudo-Second Order Model, Chemisorption, Real-Life Groundwater Samples, Adsorption, Oxyhydroxide, Bangladesh, Model, Pb

? Adak, A. and Pal, A. (2006), Removal kinetics and mechanism for crystal violet uptake by surfactant-modified alumina. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 41 (10), 2283-2297.

Full Text: 2006\J Env Sci Hea Par A-Tox Haz Sub Env Eng41, 2283.pdf

Abstract: Sodium dodecyl sulfate (SDS), an anionic surfactant (AS) was used for the surface modification of neutral alumina. Micelle-like structures are formed on the surface of alumina, which was used for the removal of crystal violet (CV), a well-known cationic dye from aquatic environment. This process is called adsolubilization. The surfactant-modified alumina (SMA) was found to be very efficient showing > 99% CV removal from a 200 ppm CV bearing solution with only 6 g/L of adsorbent dose. The kinetic studies showed that 60 minutes’ shaking time was sufficient to achieve the equilibrium. The reaction kinetics data were analysed using four reaction kinetic models, viz., first-order reaction model, pseudo-first-order reaction model, second-order reaction model and pseudo-second-order reaction model, and it was found that the removal of CV followed the pseudo-second order reaction model. It was found that neither film diffusion nor pore diffusion was rate limiting for this process. Isotherm studies showed that Langmuir isotherm fitted more accurately compared to Freundlich isotherm. To test whether the removal of CV was possible from real water using SMA, the experiments were conducted using CV spiked distilled water and synthetic wastewater. It was interesting to note that the removal efficiency was better for wastewater as compared to that of distilled water.

Keywords: Alumina, Anionic Surfactant, Sodium Dodecyl Sulfate, Adsorption, Surfactant-Modified Alumina, Crystal Violet, Removal, Adsolubilization, Textile Waste-Water, Photocatalytic Degradation, Aqueous-Solution, Dye Removal, Adsorption, Oxidation, Sorption, Adsolubilization, Decolorization, Silica

? Tunali, S., Ozcan, A., Kaynak, Z., Ozcan, A.S. and Akar, T. (2007), Utilization of the Phaseolus vulgaris L. waste biomass for decolorization of the textile dye Acid Red 57: determination of equilibrium, kinetic and thermodynamic parameters. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (5), 591-600.

Full Text: 2007\J Env Sci Hea Par A-Tox Haz Sub Env Eng42, 591.pdf

Abstract: In the present study, biosorption of Acid Red 57 (AR57) onto a waste biomass of Phaseolus vulgaris L. was investigated by varying pH, contact time, biosorbent concentration and temperature, to determine the equilibrium, thermodynamic and kinetic parameters. The AR57 biosorption was fast, and equilibrium was attained within 20 min. Biosorption equilibrium data fit the Langmuir isotherm model well with high correlation coefficients. According to Langmuir isotherm model the maximum biosorption capacity of Phaseolus vulgaris L. for AR57 dye was determined as 4.0910^-4 mol g^-1 or 215.13 mg g^-1 at 20°C. The thermodynamic parameters (Gibbs free energy, enthalpy and entropy) for the biosorption of AR57 were indicated that the biosorption was spontaneous and exothermic in nature. The pseudo-second-order kinetic model agrees well with the dynamic behavior of the biosorption of AR57 onto P. vulgaris L., under various temperatures. The removal efficiency of the biomass was also examined in real textile wastewater.

Keywords: Phaseolus Vulgaris L., Biosorption, Biosorbent, AR57, Isotherm, Kinetics, Fungus Aspergillus-Niger, Aqueous-Solution, Enteromorpha-Prolifera, Regression-Analysis, Reactive Dyes, Batch System, Removal, Biosorption, Adsorption, Water

? Aravindhan, R., Rao, J.R. and Nair, B.U. (2007), Kinetic and equilibrium studies on biosorption of basic blue dye by green macro algae Caulerpa scalpelliformis. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (5), 621-631.

Full Text: 2007\J Env Sci Hea Par A-Tox Haz Sub Env Eng42, 621.pdf

Abstract: Dynamic batch experiments were carried out for the biosorption of basic blue dye on to the green macro algae Caulerpa scalpelliformis. The factors affecting the sorption process such as the initial concentration of the dye, pH of the solution, the adsorbent dosage and the time of contact were studied. It has been observed that the sorption process was significantly affected by the pH of the initial dye solution. The sorption kinetics was found to follow the second-order kinetic model. The Boyd’s plot confirmed the external mass transfer as the rate-limiting step. The average effective diffusion coefficient was found to be 1.65210^-5 cm²/S. Sorption equilibrium studies demonstrated that the biosorption followed Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Optimized parameters were used to treat the commercial effluent containing the dye. Complete color removal was observed in two stages of treatment with the seaweed.

Keywords: Basic Blue Dye, Biosorption, Diffusion Coefficient, Equilibrium Isotherm, Green Seaweed, Macro Algae, Component Systems, Aqueous-Solution, Waste-Water, Adsorption, Removal, Peat, Isotherm, Sorption, Single, Ions

? Mohapatra, D., Mishra, D., Chaudhury, G.R. and Das, R.P. (2007), An investigation into the prospects of arsenic(V) removal from contaminated groundwater using untreated bauxite ore. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (6), 831-838.

Full Text: 2007\J Env Sci Hea Par A-Tox Haz Sub Env Eng42, 831.pdf

Abstract: Steady-state experiments were conducted on arsenic(V) removal from contaminated groundwater using two different grades of bauxite ore. The materials considered were refractory grade bauxite (RB) with high alumina and low iron content and feed bauxite (FB) with moderate alumina and high iron content. Adsorption studies were carried out for different parameters such as pH, adsorbent dosage, As(V) concentration and reaction time to establish optimum conditions. RB was found to be the better adsorbent compared to FB with a maximum As(V) adsorption capacity of 1.49 mg As(V)/g compared to 1.26 mg As(V)/g of FB. Both the adsorbents showed similar type of behavior with varying magnitude. As(V) adsorption was independent of the ionic strength suggesting an inner-sphere surface complexion mechanism. The kinetics of the As(V) adsorption could be best explained by pseudo-second-order rate equation. The adsorption was found strongly pH dependent, with maximum adsorption over a wide range of pH similar to 4.0 to 7.5. The column study results showed that at a adsorbent bed depth of 30 cm and feed flow rate of 50 ml/h, the RB was capable of treating 256 bed volumes of As(V) contaminated water (Co = 1.79 mg/L) before breakthrough (Ce = 0.01 mg/L).

Keywords: Adsorbent, Adsorbent Dosage, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Isotherm, Alumina, Arsenate Adsorption, Arsenic, As(V), Bauxite, Behavior, Breakthrough, Capacity, Chemistry, Column, Column Study, Concentration, Contaminated Water, Dosage, EXAFS, Feed, Ferrihydrite, Flow, Flow Rate, Gibbsite, Groundwater, Intra Particle Diffusion, Investigation, Ionic Strength, Iron, Kinetics, Low, Materials, Mechanism, Organic-Matter, Parameters, pH, Pseudo Second Order, Pseudo-Second-Order, Range, Rate Equation, Reaction, Reaction Time, Removal, Sorption, Speciation, Spectroscopy, Strength, Surface, Surface Complexion, Water, World

? Maji, S.K., Pal, A., Pal, T. and Adak, A. (2007), Sorption kinetics of arsenic on laterite soil in aqueous medium. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (7), 989-996.

Full Text: 2007\J Env Sci Hea Part A42, 989.pdf

Abstract: The efficiency of a locally available laterite soil in removing both arsenite and arsenate from aqueous medium by adsorption was evaluated. It was observed that in batch experiment conducted at 0.5 mg/L initial concentration of arsenic, laterite soil could remove up to 98% of arsenite and 95% of arsenate under optimized conditions. The kinetic profiles under various conditions were developed. Both arsenite and arsenate removal followed pseudo - second order reaction kinetic model. Pore and film diffusion coefficients were determined from the half-time equation and film diffusion appeared to be the rate-limiting. This was further supported by multiple interruption tests.

Keywords: Activated Carbon, Adsorbents, Adsorption, Aqueous Medium, Arsenate, Arsenate Removal, Arsenic, Arsenic Adsorption, Arsenite, As(III), As(V) Removal, Batch, Batch Experiment, Cement, Column, Concentration, Diffusion, Diffusion Coefficient, Diffusion Coefficients, Efficiency, Experiment, Film, Film Diffusion, Groundwater, Iron, Kinetic, Kinetic Model, Kinetics, Laterite, Laterite Soil, Model, Order, Profiles, Pseudo Second Order, Rate Limiting, Rate-Limiting Process, Reaction, Removal, Second Order, Soil, Tests, Water

? Sharma, V.K., Dutta, P.K. and Ray, A.K. (2007), Review of kinetics of chemical and photocatalytical oxidation of Arsenic(III) as influenced by pH. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (7), 997-1004.

Full Text: 2007\J Env Sci Hea Part A42, 997.pdf

Abstract: The kinetics and stoichiometry of As(III) oxidation by chemical oxidants is presented. The reactions are first-order with respect to each reactant. The second-order rate constants vary with pH and have a range in magnitude of 10⁴ – 10⁷ M^-1 s^-1 for free available chlorine (FAC), O₃, and FeO₄^2- in a pH range of 6.0-9.0. In this pH range, the reactions of As(III) with chloroamine (NH₂Cl) and H₂O₂ are quite slow with rate constants of 2.9-4.310^-1 M^-1 s^-1 and 2.610^-2-4.510 M^-1 s^-1 for chloroamine and H₂O₂, respectively. The pH dependence of the oxidation reactions can be described using acid-base equilibria of both As(III) species and the oxidant. FAC, O₃, and FeO₄^2- oxidize As(III) instantaneously at pH 7.0 with half-lives of milliseconds if 2 mg/L excess dose of oxidant is applied. One major advantage of FeO₄^2- ions over the other oxidants is its ability to remove arsenic in water by two mechanisms; it oxidizes As(III) and also subsequently coagulates As(V) through Fe(III) hydroxide produced from Fe(VI) reduction. Photocatalytic oxidation of As(III) to As(V) follows zero-order kinetics and the oxidation is completed in minutes with no significant pH dependence. The removal of dissolved arsenic to values below the World Health Organization drinking water limit of 10 g/L can be achieved through photocatalytic oxidation of As(III) to As(V) in acidic solution followed by adsorption of As(V) onto TiO₂ surfaces.

Keywords: Acid-Base, Adsorption, Arsenate, Arsenate Adsorption, Arsenic, Arsenite, Arsenite Oxidation, As(III), As(III) Oxidation, As(V), Chemical, Chlorine, Constants, Dependence, Dissolved, Drinking Water, Drinking-Water, Equilibria, Fe(Iii), Ferrate(VI), First Order, H₂O₂, Kinetics, Mechanisms, O₃, Oxidant, Oxidants, Oxidation, Oxygen, pH, pH Dependence, Photocatalytic, Photocatalytic Oxidation, Potassium Ferrate(VI), Range, Rate, Rate Constants, Reduction, Removal, Removal, Second Order, Species, Stoichiometry, Surfaces, TiO₂, Waste-Water, Water, Zero-Valent Iron

? Maji, S.K., Pal, A., Pal, T. and Adak, A. (2007), Modeling and fixed bed column adsorption of As(V) on laterite soil. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 42 (11), 1585-1593.

Full Text: 2007\J Env Sci Hea Part A42, 1585.pdf

Abstract: Laterite soil, an abundant locally available natural adsorbent, has been evaluated for As(V) removal from aqueous solutions in column mode operation. The column studies were conducted using columns of 10, 20, 30 cm bed depth with 2 cm internal diameter. Initial As(V) concentration was 0.5 mg/L and flow rate was 7.75 mL/min. Bohart and Adams sorption model was employed for the determination of different parameters like height of exchange zone, adsorption rate, time required for exchange zone to move, and the adsorption capacity. Effect of flow rate and initial concentration was studied. The adsorption capacity of the laterite soil for 0.5 mg/L of As(V) was found to be 62.32 mg/L, and the adsorption rate constant was 1.0911 L/mg h for the minimum bed depth of 8.47 cm. The column was designed by the BDST model. Freundlich isotherm model was used to compare the theoretical and experimental breakthrough pro. le in the dynamic process. The bed saturation obtained was 36-80%. Regeneration of the exhausted column was possible with 1M NaOH.

Keywords: Adsorbent, Adsorption, Aquatic Environment, Aqueous-Solutions, Arsenic Removal, As(III), As(V) Adsorption, BDST Model, Breakthrough Curve, Cement, Column Studies, Desorption Studies, Drinking-Water, Freundlich, Isotherm, Laterite, Laterite Soil, Modified-Alumina, Oxide, Soil, Sorption, United-States

? Smiciklas, I., Dimovic, S., Sljivic, M. and Plecas, I. (2008), The batch study of Sr²⁺ sorption by bone char. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 43 (2), 210-217.

Full Text: 2008\J Env Sci Hea Part A43, 210.pdf

Abstract: Considering the excellent sorption properties of synthetic calcium hydroxyapatite (HAP) towards many divalent cations, the potential application of bone char, the natural source of HAP, for sequestering Sr²⁺ ions from aqueous solutions has been studied in batch conditions. Contact time, initial solution pH and initial Sr²⁺ concentrations were varied to examine the effect of these process parameters on the amount of Sr²⁺ sorbed. The kinetics of Sr²⁺ sorption was found to be a 2-step process, with contact time of 24 h required for attaining equilibrium. The sorption isotherm was well fitted with Langmuir and DKR theoretical models. Sorption of Sr²⁺ on bone char was found to be a favorable, thermodynamically feasible and spontaneous process, with the maximum sorption capacity of 0.271 mmol/g and sorption energy of 11.09 kJ/mol. The sorption was pH-independent in the initial pH range 4-10, as a result of excellent buffering properties of bone char (constant final pH), while for pH > 10 sorbed amounts of Sr²⁺ increased due to attractive electrostatic forces between negatively charged sorbent surface and positively charged metal ions. On the basis of the amount of Ca²⁺ released and final pH decrease in respect to the point of zero charge of bone char (pHPZC), two possible mechanisms of Sr²⁺ sorption were identified: ion-exchange and the formation of complex compounds with HAP and carbon active surface sites. The amounts of Sr²⁺ leached from bone char increased with the increase of Ca²⁺ content and the decrease of solution pH. In comparison with synthetic HAP, bone char represents a cost-effective alternative for Sr²⁺ sequestering.

Keywords: Bone Char, Sr²⁺, Sorption, Sorption Mechanisms, Equilibrium, Kinetic, Aqueous-Solutions, Hydroxyapatite, Removal, Ions, Strontium, Adsorption, Cadmium, Surface, Metals, Carbon

? Shashirekha, V., Sridharan, M.R. and Swamy, M. (2008), Biosorption of trivalent chromium by free and immobilized blue green algae: Kinetics and equilibrium studies. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 43 (4), 390-401.

Full Text: 2008\J Env Sci Hea Part A43, 390.pdf

Abstract: The process of biosorption of trivalent chromium (Cr³⁺) by live culture of Spirulina platensis and the sorption potential by the dried biomass, in both free and immobilized states have been investigated for a simulated chrome liquor in the concentration range of 100-4500 ppm. Both live and dried biomass were very good biosorbents as they could remove high amounts of chromium from tannery wastewater. Polyurethane foam and sodium alginate were used as immobilizing agents and their performances compared. Biosorption kinetic data on Cr³⁺ sorption onto dried biomass were analyzed using pseudo-first-and pseudo-second-order kinetic models in batch column experiments. The second-order equation was more appropriate to predict the rate of biosorption. Subsequently, the effects of height of packing diameter of the column, concentration of blue-green algae (BGA) in varying amounts of sodium alginate, chromium concentration were studied. The results fit into both Langmuir Freundlich isotherm models with very high regression coefficients. Furthermore, equilibrium studies using retan chrome liquor (RCL), with a chromium concentration of 1660 ppm, obtained from a tannery also showed promising results. In general, our studies indicate the efficacy of the algal species in removal of chromium from tannery wastewater.

Keywords: Alginate, Biomass, Biosorption, Chromium, Column Experiments, Culture, Efficacy, Equilibrium, Experiments, Freundlich Isotherm, Green Algae, Immobilized, Isotherm, Kinetic, Kinetic Models, Langmuir, Models, Removal, Sorption, Wastewater

? Tang, X.W., Li, Z.Z., Chen, Y.M. and Wang, Y. (2008), Removal of Cu(II) from aqueous solution by adsorption on Chinese Quaternary loess: Kinetics and equilibrium studies. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 43 (7), 779-791.

Full Text: 2008\J Env Sci Hea Part A43, 779.pdf

Abstract: This paper dealt with the characteristics of Cu(II) adsorption on Chinese Quaternary loess. The Cu(II) adsorption isotherm and kinetics fit the Langmuir model and pseudo-second order kinetics well, respectively, with a predicted adsorption capacity of 109 mg g^-1. The adsorption is ion exchange adsorption due to D-R model. Factors that are positively correlated with the adsorption capacity of loess include equilibrating time, pH, temperature, and solid-solution ratio. The adsorption of Cu(II) on loess involves 2 - 3 sequential diffusing steps into the micropores, and an endothermic and spontaneous process with predicted enthalpy, entropy, and Gibb’s free energy changes of 7.64 kJ mol^-1, 81.21 J mol K- 1^-1 and - 14.94 - 17.37 kJ mol^-1, respectively. Moreover, the applicability of loess on industrial wastewater treatment was investigated and satisfactorily proved. Finally, FT-IR spectra shows the precipitation of copper carbonate and the complexation of Cu(II) with clay minerals at pH 5.0 and pH 2.67, respectively.

Keywords: Acid-Mine Drainage, Adsorption, Adsorption Isotherm, Aqueous Solution, Capacity, Carbonate, Changes, Chinese, Chinese Quaternary Loess, Clay, Clay Minerals, Complexation, Copper, Cu(II), Endothermic, Entropy, Equilibrium, FT-IR, FTIR, Heavy-Metals, Illite, Industrial Wastewater, Ion Exchange, Ion-Exchange, Ions, Isotherm, Kaolinite, Kinetics, Langmuir, Langmuir Model, Model, pH, Pseudo-Second Order, Remediation, Removal, Sewage-Sludge, Solution, Temperature, Thermodynamic Parameters, Thermodynamics, Treatment, Wastewater, Wastewater Treatment, Water

? Park, Y.J., Yang, J.K. and Choi, S.I. (2008), The application of reused powdered wastes as adsorbent for treating arsenic containing mine drainage. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 43 (9), 1093-1099.

Full Text: 2008\J Env Sci Hea Part A43, 1093.pdf

Abstract: This study examined the potential reuse of powdered wastes (PW) generated during the sanding and sawing process in a local chemical company in Korea with the viewpoint of the recycling these wastes and minimizing the level of contamination. The PW contained 40-60% aluminum hydroxide and 30-45% matrix resin. As a potential adsorbent, the suitability of thermal treated PW to remove arsenic from synthetic and real wastewater was investigated. As a pretreatment process, the reused adsorbent from PW was calcined at 550°C for 3 hrs in a furnace. The calcination characteristics of PW were examined both quantitatively and qualitatively by X-ray fluorescence (XRF), and qualitatively by X-ray diffraction (XRD). The major inorganic composition of the calcined PW (CPW) was aluminum oxide with poor crystallinity. The CPW contained well developed meso-pores (0.143 cm³ g^-1) and showed a specific surface area of 234 m² g^-1. The pH of the zero point charge (pHpzc) of the CPW was determined to be 7.8 by acid-base titration. From the batch adsorption tests, the complete removal of arsenic (up to 20 mg L^-1) was observed with CPW (2 g) at pH ranging from 3.0 to 8.0. However, there was a significant decrease in arsenate adsorption at higher pH. A kinetics study indicated that the uptake of arsenate followed a second-order rate equation. In the presence of sulfate, the removal of arsenate was increasingly affected by the sulfate concentration. The application of CPW to the removal of 4 different real mine drainages was also carried out. Mine drainage contains a relatively high arsenate concentration as well as sulfate. Whilst the amount of arsenic removed from real mine drainage by CPW was slightly lower than that removed from synthetic wastewater due to competitive sorption by multiple ions, the adsorption of arsenate showed rapid removal within 10 min with good removal efficiency, which meets the national wastewater discharge limits. These results suggest that CPW is a good adsorbent for removing arsenic from synthetic and real mine drainage.

Keywords: Adsorbent, Adsorption, Adsorption, Alumina, Aluminum Oxide, Aqueous-Solutions, Arsenate, Arsenic, Batch Adsorption, Calcination, Calcined, Carbon, Charge, Dependence, Efficiency, Interface, Kinetics, Korea, Mechanisms, Mine Drainage, Oxide, pH, pH_PZC, Potential, Powdered Wastes, Pretreatment, Recycling, Removal, Removal Efficiency, Resin, Second Order, Second-Order, Sorption, Specific Surface, Sulfate, Surface Area, Surface-Charge, Wastewater, X-Ray Diffraction, XRD, Zero Point Charge

? Bulgariu, L., Răţoi, M., Bulgariu, D. and Macoveanu, M. (2009), Adsorption potential of mercury(II) from aqueous solutions onto Romanian peat moss. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 44 (7), 700-706.

Full Text: 2009\J Env Sci Hea Par A44, 700.pdf

Abstract: This study was undertaken to evaluate the adsorption potential of Romanian peat moss for the removal of mercury(II) from aqueous solutions. The batch system experiments carried out showed that this natural material was effective in removing mercury(II). The analysis of FT-IR spectra indicated that the mechanism involved in the adsorption can be mainly attributed to the binding of mercury(II) with the carboxylic groups of Romanian peat moss. Adsorption equilibrium approached within 60 min. The adsorption data fitted well the Langmuir isotherm model. The maximum adsorption capacity (q_max) was 98.94 mg g^-1. Pseudo-second-order kinetic model was applicable to the adsorption data. The thermodynamic parameters indicate that the adsorption process was spontaneous as the Gibbs free energy values were found to be negative (between -17.58 and -27.25 kJ mol^-1) at the temperature range of 6-54C.

Keywords: Adsorption, Adsorption Capacity, Adsorption Equilibrium, Analysis, Aqueous Solutions, Batch, Batch System, Binding, Biosorbents, Biosorption, Capacity, Carboxylic, Copper, Data, Energy, Equilibrium, Experiments, FT-IR, FTIR, FTIR Spectra, Gibbs Free Energy, Heavy-Metals, Isotherm, Isotherm Model, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Mechanism, Mercury(II), Model, Models, Natural, Peat, Peat Moss, Potential, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Removal, Romanian Peat Moss, Solutions, Sorbents, Sorption, Temperature, Thermodynamic, Thermodynamic Parameters, Waste-Water

? Shah, B.A., Shah, A.V., Singh, R.R. and Patel, N.B. (2009), Sorptive removal of nickel onto weathered basaltic andesite products: Kinetics and isotherms. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 44 (9), 880-895.

Full Text: 2009\J Env Sci Hea Pat A-Tox Haz Sub Env Eng44, 880.pdf

Abstract: The suitability of weathered basaltic andesite products (WBAP) as a potential sorbent was assessed for the removal of Ni(II) from electroplating industrial wastewater. A model study based on the batch mode of operation was carried out for Ni(II) removal from aqueous solution. The effect of various parameters such as hydronium ion concentration, shaking time, sorbent dose, initial Ni(II) concentration, and temperature on the sorption process was studied. At optimised conditions of the various parameters, the industrial wastewater loaded with Ni(II) was sorbed onto WBAP Thermodynamic parameters for the sorption process were evaluated. Freundlich, Langmuir, Temkin, and Dubinin-Kaganer-Radushkevich isotherms were applied to the sorption pattern on the WBAP. The sorption dynamics of the process was evaluated by applying Lagergren, Bangham, and Weber & Morris equations. The sorption process follows Pseudo-second-order rate of surface diffusion which is identified as the predominating mechanism. The sorption process was found to be reversible by the recovery of sorbed Ni(II) upon extraction with 0.5 M HNO₃. The sorbent before and after sorption, was characterized by Fourier transform infrared (FTIR),. Powder X-Ray diffraction PXRD), and Thermogravimetric analysis (TGA) methods. The change in surface morphology and crystallanity of the mineral after sorption was analyzed by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). Based on the previous model study, an electroplating industrial effluent was successfully treated with WBAP to minimize the pollution load caused by Ni(II).

Keywords: Adsorbent, Adsorptive Removal, Analysis, Aqueous Solution, Aqueous-Solutions, Batch, Batch Mode, Concentration, Diffusion, Dynamics, Electron Microscopy, Electroplating Industrial Effluent, Electroplating Wastewater, Extraction, Fly-Ash, Freundlich, FTIR, Heavy-Metals, Industrial Effluent, Industrial Wastewater, Ion-Exchange-Resins, Isotherms, Kinetics, Langmuir, Load, Mechanism, Metal-Ions, Methods, Mode, Model, Morphology, Nickel, Operation, Pattern, Peat, Pollution, Pollution Load, Potential, Pseudo-Second-Order, Recovery, Removal, SEM, Solution, Sorbent, Sorbent Dose, Sorption, Sorption Process, Surface, Surface Diffusion, TEM, Temperature, TGA, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Waste-Water, Wastewater, Weathered Basaltic Andesite Products

? Oh, S. and Shin, W.S. (2010), Effect of ageing on desorption of lead and cadmium from sediments: Kinetics and desorption-resistance. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 45 (9), 1150-1168.

Full Text: 2010\J Env Sci Hea Par A-Tox Haz Sub Env Eng45, 1150.pdf

Abstract: In this study, the effect of ageing on sorption isotherms and desorption behaviors (kinetics and desorption-resistance) of lead (Pb) and cadmium (Cd) in natural sediments was investigated. Several sorption models such as Freundlich, Langmuir and Dubinin-Radushkevich models were fitted to the sorption data. The sorption affinity and sorption capacity of the heavy metals onto sediments increased with cation exchange capacity (CEC) and BET surface area (A(BET)). The sorption affinity of Pb was higher than that of Cd in all sediments at all ageing time scales (1, 30 and 100 d). Four different models: the one-site mass transfer model (OSMTM), the pseudo-first-order kinetic model (PFOKM), the pseudo-second-order kinetic model (PSOKM) and the two compartment first-order kinetic model (TCFOKM) were used to analyze desorption kinetics. All models predicted that the sorbed amount (q(e,s)) at the apparent desorption equilibria increased as the cation exchange capacity (CEC) and BET surface area (A(BET)) of the sediments increased. However, the fast desorption fractions (f(1,d)) decreased with increasing CEC, A(BET) and organic carbon content (f(oc)). Sequential desorption experiments were conducted to investigate the effect of ageing on desorption-resistance and a biphasic desorption model was fitted to the data. The biphasic desorption model parameters indicate that the maximum capacity of desorption resistant fraction (q(max)(irr)) of Pb was higher than that of Cd and the q(max)(irr) increased with CEC, A(BET) and ageing time for both Pb and Cd. Sequential extraction analysis revealed that the transformation of heavy metals in more mobile fraction into less mobile fractions was the main reason for the increase in desorption-resistance.

Keywords: Adsorption, Ageing, Analysis, BET, BET Surface Area, Cadmium, Capacity, Carbon, Cation Exchange, Cation Exchange Capacity, Data, Desorption, Desorption Kinetics, Desorption-Resistance, Dubinin-Radushkevich, Exchange, Extraction, Fe, Freundlich, Heavy Metals, Heavy-Metals, Isotherms, Kinetic, Kinetic Model, Kinetics, Langmuir, Lead, Mass Transfer, Metals, Model, Model Parameters, Models, Pb, Pseudo Second Order, Pseudo-Second-Order, Release, Sediment, Sequential Extraction, Sequential Extraction Procedure, Soils, Sorption, Sorption Capacity, Sorption Isotherm, Sorption Isotherms, Surface Area, Time, Trace-Metals, Zn

? Mathieu, J.L., Gadgil, A.J., Addy, S.E.A. and Kowolik, K. (2010), Arsenic remediation of drinking water using iron-oxide coated coal bottom ash. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 45 (11), 1446-1460.

Full Text: 2010\J Env Sci Hea Par A-Tox Haz Sub Env Eng45, 1446.pdf

Abstract: We describe laboratory and field results of a novel arsenic removal adsorbent called ‘Arsenic Removal Using Bottom Ash’ (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (similar to$0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R-2 = 0.77) ARUBA’s adsorption capacity in treating real groundwater is 2.6×10⁶ mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo-second-order kinetic model, R² >= 0.99) increase from 2.4×10⁵ to 7.2×10⁵ g mol^-1min^-1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA’s arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA’s AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.

Keywords: Adsorbent, Adsorption, Adsorption Capacity, Affordability, Arsenic, Arsenic Adsorption, Arsenic Remediation, Arsenic Removal, Bangladesh, Bangladesh, Bottom Ash, Capacity, Coagulation, Coal, Coal Bottom Ash, Coated, Coating, Community, Competitive Adsorption, Concentration, Contaminated Groundwater, Costs, Drinking Water, Equilibrium, Field, Filtration, Fly-Ash, Ground-Water, Groundwater, Interval, Iron, Iron Oxide, Iron-Oxide, Isotherm, Kinetic, Kinetic Model, Langmuir, Langmuir Isotherm, Model, Particles, Phosphate, Plants, Potential, Power, Pressure, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Public-Health, Rates, Remediation, Removal, Room Temperature, Sand, Scale, Source, Standard, Temperature, Treatment, Waste, Water, Water Contaminants, Water Treatment, Zero-Valent Iron, Zerovalent Iron

? El-Said, G.F. and Draz, S.E.O. (2010), Physicochemical and geochemical characteristics of raw marine sediment used in fluoride removal. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 45 (12), 1601-1615.

Full Text: 2010\J Env Sci Hea Par A-Tox Haz Sub Env Eng45, 1601.pdf

Abstract: The study was directed to use raw marine sediment in the removal of fluoride. The sediment was mainly composed of calcite, magnesium-calcite and aragonite. The effect of the initial fluoride concentration, pH and the contact time was studied at room temperature to determine the adsorption capacity of the sediment. The optimum adsorption capacity was observed at pH values of 5 and 6.2. The adsorption process was fast and the equilibrium was reached within 60 min. For fluoride solutions of 10 and 15 mg/L, 100% removal was obtained onto 0.1 g of raw marine sediment. Pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion equations were used to deduce the kinetic data. The adsorption mechanism was rather complex process, and the intra-particle diffusion was not the only rate-controlling step. The equilibrium data were tested using thirteen isotherm models (Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich, Erunauer-Emmett-Teller, Flory-Huggins, Non-ideal competitive adsorption, Generalized, Redlich Peterson, Khan, Sips, Koble Corrigan and Toth isotherm equations). Five different error functions were applied. For the sorption of fluoride process, the calculated activation energy and the free energy were of 0.707 and -14.491 kJ/mol, respectively.

Keywords: Activated Carbon, Activation, Activation Energy, Adsorption, Adsorption And Kinetics Isotherms, Adsorption Capacity, Adsorption Mechanism, Adsorption-Isotherm, Aqueous-Solution, Calcite, Capacity, Characteristics, Competitive, Competitive Adsorption, Concentration, Data, Diffusion, Drinking-Water, Elovich, Elovich Equation, Energy, Equilibrium, Error, Error Analysis, Fluoride, Fluoride Removal, Freundlich, Functions, Geochemical, Intra-Particle Diffusion, Intraparticle Diffusion, Ion-Exchange, Isotherm, Isotherm Equations, Isotherm Models, Kinetic, Kinetics, Langmuir, Marine Sediment, Mechanism, Models, pH, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Raw Marine Sediment, Redlich-Peterson, Removal, Room Temperature, Sediment, Solutions, Sorption, Temperature, Waste-Water

? Zhao, Y.Q. and Babatunde, A.O. (2011), Foreword. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 46 (7), 677-679.

Full Text: 2011\J Env Sci Hea Par A-Tox Haz Sub Env Eng46, 677.pdf