Personal Research Database

Full Text: J\J Haz Mat121, 61.pdf

Abstract: Batch and column experiments were conducted to investigate the effect of dissolved oxygen (DO) and pH on arsenic removal with zero-valent iron [Fe(0)]. Arsenic removal was dramatically affected by the DO content and the pH of the solution. Under oxic conditions, arsenate [As(V)] removal by Fe(0) filings was faster than arsenite [As(III)]. Greater than 99.8% of the As(V) was removed whereas 82.6% of the As(III) was removed at pH 6 after 9 h of mixing. When the solution was purged with nitrogen gas to remove DO, less than 10% of the As(III) and As(V) was removed. High DO content and low solution pH also increased the rate of iron corrosion. The removal of arsenic by Fe(0) was attributed to adsorption by iron hydroxides generated from the oxic corrosion of Fe(0). The column results indicated that a filtration system consisting of an iron column and a sand filter could be used for treatment of arsenic in drinking water.

Keywords: Arsenic, Iron, Adsorption, Groundwater, Filtration

? Tuzen, M., Parlar, K. and Soylak, M. (2005), Enrichment/separation of cadmium(II) and Lead(II) in environmental samples by solid phase extraction. Journal of Hazardous Materials, 121 (1-3), 79-87.

Full Text: J\J Haz Mat121, 79.pdf

Abstract: A preconcentration/separation procedure is presented for the solid phase extraction of trace cadmium and lead ions as their 1-(2-pyridylazo) 2-naphthol (PAN) chelates in environmental samples on Chromosorb-106 resin, prior to cadmium and lead determinations by atomic absorption spectrometry. The preconcentration procedure was optimized by using model solutions containing cadmium and lead ions. The influences of pH of the model solutions, amounts of PAN, eluent type and volume etc. were investigated. Also the effects of the matrix constituents of the samples were also examined. Separation of cadmium and lead from real samples was achieved quantitatively. The procedure presented was checked with the analysis of microwave-digested standard reference materials (IAEA-336 Lichen and SRM 1515 Apple leaves). The preconcentration procedure was applied for the lead and cadmium contents of the natural water samples, some salts with satisfactory results (recoveries >95%, relative standard deviations <8%).

Keywords: Preconcentration, Chromosorb-106, Solid Phase Extraction, Environmental Samples, Atomic Absorption Spectrometry

? Krishna, K.R. and Philip, L. (2005), Bioremediation of Cr(VI) in contaminated soils. Journal of Hazardous Materials, 121 (1-3), 109-117.

Full Text: J\J Haz Mat121, 109.pdf

Abstract: Ex situ treatment of hexavalent chromium (Cr(VI)) contaminated soil using a bioreactor–biosorption system was evaluated as a novel remediation alternative. Leaching of Cr(VI) from the contaminated soil using various eluents showed that desorption was strongly affected by the solution pH. The leaching process was accelerated at alkaline conditions (pH 9). Though, desorption potential of ethylene diamine tetra acetic acid (EDTA) was the maximum among various eluents tried, molasses (5 g/L) could also elute 72% of Cr(VI). Cr(VI) reduction studies were carried out under aerobic and facultative anaerobic conditions using the bacterial isolates from contaminated soil. Cr(VI) reduction was moderately higher in aerobic conditions than in facultative anaerobic conditions. The effect of various electron donors on Cr(VI) reduction was also investigated. Among five electron donors screened, peptone (10 g/L) showed maximum Cr(VI) reduction followed by molasses (10 g/L). The time required for complete Cr(VI) reduction was increased with increase in the initial Cr(VI) concentration. However, specific Cr(VI) reduction was increased with increase in initial Cr(VI) concentration. Sulfates and nitrates did not compete with Cr(VI) for accepting the electrons. A bioreactor was developed for the detoxification of Cr(VI). Above 80% of Cr(VI) reduction was achieved in the bioreactor with an initial Cr(VI) concentration of 50 mg/L at an HRT of 8 h. An adsorption column was developed using Ganoderm lucidum (a wood rooting fungus) as the adsorbent for the removal of trivalent chromium (Cr(III)) and excess electron donor from the effluent of the bioreactor. The specific Cr(III) adsorption capacity of G. lucidum in the column was 576 mg/g. The new biosystem seems to be a promising alternative for the ex situ bioremediation of Cr(VI) contaminated soils.

Keywords: Biotransformation, Biosorption, Contaminated Soil, Hexavalent Chromium, Ganoderma Lucidum

? Yapar, S., Özbudak, V., Dias, A. and Lopes, A. (2005), Effect of adsorbent concentration to the adsorption of phenol on hexadecyl trimethyl ammonium-bentonite. Journal of Hazardous Materials, 121 (1-3), 135-139.

Full Text: J\J Haz Mat121, 135.pdf

Abstract: In this work, it is intended to study the effect of adsorbent concentration on the adsorption of phenol by hexadecyl trimethyl ammonium-bentonite. The experiments were conducted in two groups. The adsorption of hexadecyl trimethyl ammonium bromide (HDTMA) on bentonite was studied in the first group of experiments. It was observed that the all HDTMA was adsorbed by the bentonite, even when the amount used exceeded 100% of cation exchange capacity (CEC). After the modification of bentonite by using HDTMA in an amount equivalent to 100% of CEC, the adsorption experiments were performed at five different adsorbent concentrations ranging from 2 to 10 g/L. A type V isotherm and a non-linear increase in percent removal with adsorbent concentration were observed. The observation of the non-linear relation between the percent removal and adsorbent concentration was attributed to the effect of intra particle interactions and it was represented by a second order polynomial. Several adsorption isotherm equations were applied to the experimental data. Although, the Freundlich equation fitted fairly well, it failed to represent the plateau and the second region that appeared in the isotherm. Therefore, an equation giving the equilibrium concentration as a function of initial and adsorbent concentrations was suggested.

Keywords: HDTMA, Organo-bentonite, Adsorption Isotherm, Adsorbent Concentration

? Deydier, E., Guilet, R., Sarda, S. and Sharrock, P. (2005), Physical and chemical characterisation of crude meat and bone meal combustion residue: “waste or raw material?” Journal of Hazardous Materials, 121 (1-3), 141-148.

Full Text: 2005\J Haz Mat121, 141.pdf

Abstract: As a result of the recent bovine spongiform encephalopathy (BSE) crisis in the European beef industry, the use of animal by-product is now severely controlled. Meat and bone meal (MBM) production can no longer be used to feed cattle and must be safely disposed of or transformed. Main disposal option is incineration, producing huge amounts of ashes the valorisation of which becomes a major concern. The aim of this work is to characterise MBM combustion residue in order to evaluate their physical and chemical properties to propose new valorisation avenues. The thermal behaviour of crude meat and bone meal was followed by thermogravimetric analysis (TGA) and (24 wt.%) inorganic residue was collected. The resulting ashes were characterised by powder X-ray diffraction (XRD), particle size distribution, specific surface area (BET), scanning electron microscopy (SEM) couple with energy disperse X-ray analysis (EDX). Elemental analysis revealed the presence of chloride, sodium, potassium, magnesium with high level of phosphate (56 wt.%) and calcium (31 wt.%), two major constituents of bone, mainly as a mixture of Ca-10(PO4)(6)(OH)(2) and Ca-3(PO4)(2) phases. The impact of combustion temperature (from 550 to 1000&DEG; C) on the constitution of ashes was followed by TGA, XRD and specific surface measurements. We observed a strong decrease of surface area for the ashes with crystallisation of calcium phosphates phases without major changes of chemical composition. © 2005 Elsevier B.V. All rights reserved.

Keywords: Analysis, Apatite, Apatite, Ashes, Bone, Bovine, Calcium, Cattle, Characterisation, Chemical, Chemical Characterisation, Chemical Composition, Chemical Properties, Chloride, Combustion, Combustion Residue, Composition, Crisis, Disposal, Distribution, EDX, Electron Microscopy, Energy, Feed, Hydroxyapatite, Impact, Incineration, Inorganic, Ions, Lead Immobilization, Magnesium, Measurements, Meat, Meat and Bone Meal, Metals, Microscopy, Mixture, Particle, Particle Size, Particle Size Distribution, Phosphate, Phosphate Sources, Phosphates, Physical, Potassium, Prions, Production, Properties, Recent, Removal, Residue, Scanning Electron Microscopy, SEM, Size Distribution, Sodium, Soils, Sorption, Specific Surface, Specific Surface Area, Surface, Surface Area, Temperature, Thermogravimetric, Thermogravimetric Analysis, Valorisation, X-Ray Diffraction, XRD

? Prasad, G.K., Singh, B., Suryanarayana, M.V.S. and Batra, B.S. (2005), Kinetics of degradation of sulphur mustard on impregnated carbons. Journal of Hazardous Materials, 121 (1-3), 159-165.

Full Text: 2005\J Haz Mat121, 159.pdf

Abstract: Kinetics of degradation of sulphur mustard (HD) on the surface of NaOH, CrO₃, C, NaOH, CrO₃, EDA, C and RuCl₃, C systems has been examined by using gas chromatography technique by extracting and analyzing the residual HD periodically. The carbons were prepared by impregnating activated carbon with 4% sodium hydroxide plus 3% Cr(VI) as CrO₃ with and without 5% ethylene diamine (EDA) and 5% ruthenium chloride by using their aqueous solutions. Obtained carbons were characterized for surface area analysis by BET conventional method. Kinetic plots reveal that the observed reactions are fast at the initial stages, slow at the later stages and progress to a steady state indicating the first order behavior. Effect of moisture on kinetic rate is also observed. In the case of NaOH, CrO₃, C system the rate constant is decreased from 13.36 to 5.5310^-2 h^-1 and half life is increased from 5.2 to 12.54h while moisture content is increased from 1.9% to 11.2%. Whereas, the rate constant of HD degradation reaction is decreased from 10.4 to 4.1410^-2 h^-1 and half life is increased from 6.7 to 16.72h while moisture content is increased from 2.1% to 10.8% on NaOH, CrO₃, EDA, C. Reaction on RuCl₃, C system also behaves in the similar manner. Extracted reaction products were characterized by GC, MS and it is found that on NaOH, CrO₃, C, HD degrades to hemisulphur mustard, thiodiglycol and 1,4-oxathiane. Whereas, on NaOH, CrO₃, EDA, C, HD is degraded to 1,4-thiazane and it is degraded to divinyl sulphone on RuCl₃, C. All these investigations reveal that above mentioned carbons can be used in nuclear, biological and chemical (NBC) filtration systems for protection against sulphur mustard. © 2005 Elsevier B.V All rights reserved.

Keywords: Activated Carbon, Active-Carbon, Adsorption, Adsorption, Analysis, Aqueous Solutions, Behavior, BET, Biological, Carbon, Chemical, Chemical Warfare Agent, Chloride, Chromatography, Chromium, Content, Conventional, Copper, Cr(VI), Cyanogen Chloride, Degradation, EDA, Filtration, First, First Order, Gases, GC, MS, Half-Life, HD, Impregnation, Investigations, Kinetic, Kinetics, Life, Moisture, Progress, Protection, Rate Constant, Rights, Ruthenium, Silver, Sodium, Solutions, State, Steady State, Sulphur Mustard, Surface, Surface Area, Systems, Technique, X

? Chojnacka, K. (2005), Biosorption of Cr(III) ions by eggshells. Journal of Hazardous Materials, 121 (1-3), 167-173.

Full Text: J\J Haz Mat121, 167.pdf

Abstract: The paper presents results of studies carried out on sorption of Cr(III) ions from aqueous solutions by eggshells as a low-cost sorbent. It was found that crushed eggshells posses relatively high sorption capacity, when comparing with other sorbents, that was evaluated as 21–160 mg/g. The effect of process parameters: pH, temperature, initial concentration of Cr(III) ions on the process kinetics was studied. It was found that the equilibrium of the process was reached after 60 min. Also equilibrium studies were performed: the effect of sorbent concentration and equilibrium Cr(III) concentration was studied. The maximum experimentally determined sorption capacity 160 mg/g was obtained at low sorbent concentration at 20 °C and pH 5. It was found that sorption capacity increased with the increase of Cr(III) concentration, temperature and sorbent concentration. Mathematical models describing kinetics and equilibrium of sorption were proposed. The process kinetics was described with pseudo-second-order pattern and equilibrium was described with Langmuir-type equation, and the influence of sorbate concentration, with an empirical dependence. The models were positively verified. Eggshells were able to remove the concentration of Cr(III) ions below the acceptable level, i.e. at 40 °C, at the initial concentration of metal ions 100 mg/kg, at sorbent concentration 15 g/l.

Keywords: Aqueous Solutions, Biosorption, Capacity, Concentration, Cr(III), Cr(III) Ions, Eggshells, Equilibrium, Equilibrium Studies, Kinetics, Metal, Metal Ions, Modelling, Models, Pattern, pH, Pseudo Second Order, Pseudo-Second-Order, Solutions, Sorbate, Sorbent, Sorbents, Sorption, Sorption Capacity, Temperature

? Coleman, N.J., Lee, W.E. and Slipper, I.J. (2005), Interactions of aqueous Cu²⁺, Zn²⁺ and Pb²⁺ ions with crushed concrete fines. Journal of Hazardous Materials, 121 (1-3), 203-213.

Full Text: J\J Haz Mat121, 203.pdf

Abstract: The crushing of reclaimed concrete-based demolition waste to produce recycled aggregate gives rise to a large volume of cement-rich fine material for which market development would be beneficial. It was envisaged that this fine fraction may prove to be an effective sorbent for aqueous heavy metal species by virtue of its ion exchangeable phases and high pH.

A batch sorption study confirmed that crushed concrete, in the particle size range 1–2 mm, successfully excluded Cu²⁺ (35 mg g⁻¹), Zn²⁺ (33 mg g⁻¹) and Pb²⁺ (37 mg g⁻¹) from aqueous media. Subsequent distilled water leaching of the metal-laden concrete particles indicated that 1.9, 0.9 and 0.2% of the bound metals, Cu²⁺, Zn²⁺ and Pb²⁺, respectively, were readily soluble. Scanning electron microscopy revealed that the removal of Cu²⁺ and Zn²⁺ arose from surface precipitation reactions, whereas, the principal mechanism of uptake of Pb²⁺ was found to be by diffusion into the cement matrix. The metal ion removal efficiency of crushed concrete fines is compared with those of other low cost sorbents and potential applications which may exploit this sorptive property are also discussed.

Keywords: Recycling, Cement, Demolition Waste, Heavy Metal Ions, Sorbent

? Erses, A.S., Fazal, M.A., Onay, T.T. and Craig, W.H. (2005), Determination of solid waste sorption capacity for selected heavy metals in landfills. Journal of Hazardous Materials, 121 (1-3), 223-232.

Full Text: J\J Haz Mat121, 223.pdf

Abstract: The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities for heavy metals on a solid waste matrix were investigated. Five heavy metals (iron, copper, zinc, nickel and cadmium) were chosen because of their availability in any landfill site. The conditions during all the experimental runs were pH 7.0, temperature 32 °C and suppressed microbial degradation. For adsorption isotherm (Freundlich and Langmuir) calculations, fixed quantities of heavy metal ions were mixed with variable quantities of solid waste. The ratio of mass of adsorbate per unit mass of adsorbent was changed five times, by changing only the adsorbent amount. The results showed that the time required to reach equilibrium varied from metal to metal but all reached equilibrium within the first 32 h. The relative potential of sorption of the individual metals and mixed metals on the solid waste matrix is Fe > Zn > Cu > Ni > Cd. The sorption capacity of domestic solid waste matrix for heavy metals is quite significant and this property might prove helpful for the in situ removal of heavy metals in landfill operation.

Keywords: Solid Waste, Landfill, Heavy Metals, Sorption, Equilibrium Time, Adsorption Isotherm, Freundlich Isotherm, Langmuir Isotherm

? Pan, B.C., Zhang, X., Zhang, W.M., Zheng, J.Z., Pan, B.J., Chen, J.L. and Zhang, Q.X. (2005), Adsorption of phenolic compounds from aqueous solution onto a macroporous polymer and its aminated derivative: Isotherm analysis. Journal of Hazardous Materials, 121 (1-3), 233-241.

Full Text: J\J Haz Mat121, 233.pdf

Abstract: Adsorption of phenolic compounds from aqueous solution to a macroporous polymeric adsorbent (CHA-111), its animated derivative (MCH-111) and a reference weakly anion exchanger (ND-900) was studied. Experimental results indicated that amino functional groups on the polymeric matrix play an important role in phenol adsorption by MCH-111 and ND-900, which was attributed to the formation of hydrogen bonding between the phenol molecule and the amino group on the polymeric matrix. The semi-empirical Freundlich isotherm equation and its reduced form were employed to interpret the adsorption behavior. A site energy distribution model based on the Polanyi adsorption potential theory can elucidate the adsorption mechanism reasonably.

Keywords: Phenolic Compounds, Adsorption Isotherm, Polymeric Adsorbent, Amination, Site Energy Distribution

? Shukla, S.S., Yu, L.J., Dorris, K.L. and Shukla, A. (2005), Removal of nickel from aqueous solutions by sawdust. Journal of Hazardous Materials, 121 (1-3), 243-246.

Full Text: J\J Haz Mat121, 243.pdf

Abstract: The main parameters influencing Nickel(II) metal sorption on maple sawdust were: initial metal ion concentration, amount of adsorbent, and pH value of solution. The maximum percent metal removal was attained after about 1 h. The greatest increase in the rate of adsorption of metal ions on sawdust was observed for pH changes from 2 to 5. An empirical relationship has been obtained to predict the percentage Nickel(II) removal at any time for known values of sorbent and initial sorbate concentration. The experimental results provided evidence for chelation ion exchange as the major adsorption mechanisms for binding metal ions to the sawdust. The adsorbent can be effectively regenerated using 0.1 M strong acid and reused.

Keyword: Maple Sawdust, Heavy Metals, Nickel, Adsorption, Wastewater

? Gong, R., Li, M., Yang, C., Sun, Y.Z. and Chen, J. (2005), Removal of cationic dyes from aqueous solution by adsorption on peanut hull. Journal of Hazardous Materials, 121 (1-3), 247-250.

Full Text: J\J Haz Mat121, 247.pdf

Abstract: The potential feasibility of peanut hul particle for removal of three cationic dyes (methylene blue, brilliant cresyl blue and neutral red) from aqueous solution was investigated. The effects of various experimental parameters were examined and optimal experimental conditions were decided. Above the value of initial pH 4, three dyes studied could be removed effectively. The isothermal data fitted the Langmuir model or Freundlich model. The adsorption processes followed the pseudo-first-order rate kinetics. The results in this study indicated that peanut hull was an attractive candidate for removing cationic dyes from dye wastewater.

Keywords: Adsorption, Cationic Dye, Methylene Blue, Brilliant Cresyl Blue, Neutral Red, Peanut Hull

? Lin, C.C. and Lin, H.L. (2005), Remediation of soil contaminated with the heavy metal (Cd²⁺). Journal of Hazardous Materials, 122 (1-2), 7-15.

Full Text: J\J Haz Mat122, 7.pdf

Abstract: Soil contamination by heavy metals is increasing. The biosorption process for removal of the heavy metal Cd²⁺ from contaminated soil is chosen for this study due to its economy, commercial applications, and because it acts without destroying soil structure. The study is divided into four parts (1) soil leaching: the relationships between the soil leaching effect and agitation rates, solvent concentrations, ratios of soil to solvent, leaching time and pH were studied to identify their optimum conditions; (2) adsorption Cd²⁺ tests of immobilized Saccharomycetes pombe beads: different weight percentages of chitosan and polyvinyl alcohol (PVAL) were added to alginate (10 wt.%) and then blended or cross-linked by epichlorohydrin (ECH) to increase their mechanical strength. Next, before blending or cross-linking, different weight percentages of S. pombe 806 or S. pombe ATCC 2476 were added to increase Cd²⁺ adsorption. Thus, the optimum beads (blending or cross-linking, the percentages of chitosan, PVAL and S. pombe 806 or S. pombe ATCC 2476) and the optimum adsorption conditions (agitation rate, equilibrium adsorption time, and pH in the aqueous solution) were ascertained; (3) regeneration tests of the optimum beads: the optimum beads adsorbing Cd²⁺ were regenerated by various concentrations of aqueous HCl solutions. The results indicate that the reuse of immobilized pombe beads was feasible; and (4) adsorption model/kinetic model/thermodynamic property: the equilibrium adsorption, kinetics, change in Gibbs free energy of adsorption of Cd²⁺ on optimum beads were also investigated.

Keywords: Soil Leaching, Cadmium, Chitosan, Immobilized Saccharomycetes Pombe Bead, Regeneration

? Kim, H.J., Baek, K., Kim, B.K. and Yang, J.W. (2005), Humic substance-enhanced ultrafiltration for removal of cobalt. Journal of Hazardous Materials, 122 (1-2), 31-36.

Full Text: J\J Haz Mat122, 31.pdf

Abstract: It is well known that the membrane separation process combined with surfactant micelle (micellar-enhanced ultrafiltration) or polyelectrolyte (polyelectrolyte-enhanced ultrafiltration) can remove heavy metal ions or radionuclides effectively. However, the complexing agent, surfactant or polyelectrolyte remained in effluent is a serious disadvantage of these methods. In this study, humic substances (HS) were used as complexing agents instead of synthetic chemicals. The HS are sorts of natural organic matters and their functional groups such as carboxyl and phenyl groups can bind with the cation and form complexes. The effects of HS concentration and pH on the removal of cobalt were investigated. At the HS concentration of 3 g/L and pH of 6, over 95% of cobalt was removed by regenerated cellulose membrane with molecular weight cut-off (MWCO) of 3000. As the HS concentration increased, the removal of cobalt was also enhanced because of the increase in binding sites (functional groups). The removal of cobalt increased from 72.5% to 97.5% as pH increased from 4 to 8 at the HS concentration of 3 g/L. It resulted from the more deprotonation of functional groups in humic acid at higher pH.

Keywords: Humic Acid, Cobalt, Complexation, Electrolyte, Ultrafiltration

? Ravikumar, K., Deebika, B. and Balu, K. (2005), Decolourization of aqueous dye solutions by a novel adsorbent: Application of statistical designs and surface plots for the optimization and regression analysis. Journal of Hazardous Materials, 122 (1-2), 75-83.

Full Text: J\J Haz Mat122, 75.pdf

Abstract: Adsorption of Neolan Blue 2G (Acid Blue 158) and Basic Methylene Blue (Basic Blue 9) was investigated using a hybrid adsorbent that was prepared by pyrolysing a mixture of carbon and flyash at 1:1 ratio. A 2⁴ full factorial central composite design with nine replicates at the center point and thus a total of 31 experiments were successfully employed for batch experimental design and analysis of the results. The combined effect of pH, temperature, particle size and time on the dye adsorption was studied. An empirical model was developed and validated applying ANOVA analysis incorporating interaction effects of all parameters and optimized using response surface methodology. The optimum pH, temperature, particle size and time were found to be 2.20, 27.85°C, 0.0565 mm, 245 min, respectively, for Acid Blue 158 and those for Basic Blue 9 were 13.40, 28.45°C, 0.0555 mm and 230 min, respectively. Complete removal (100%) was observed for both the dyes using the hybrid adsorbent.

Keywords: Adsorption, Hybrid Adsorbent, Dye Removal, Response Surface Methodology, Statistical Analysis

? Meena, A.K., Mishra, G.K., Rai, P.K., Rajagopal, C. and Nagar, P.N. (2005), Removal of heavy metal ions from aqueous solutions using carbon aerogel as an adsorbent. Journal of Hazardous Materials,