Personal Research Database

Full Text: 2007\J Haz Mat142, 449.pdf

Abstract: Cr(VI) is a priority pollutant and has been documented to be harmful to fauna, flora and human beings and chromium containing water and wastewater are hazardous. Removal of Cr(VI) by adsorption on a non-toxic natural substance, riverbed sand has been investigated. A maximum removal of 74.3% was noted at 0.50×10⁻⁴ M concentration of Cr(VI) in solution. Kinetic and equilibrium studies of Cr(VI) removal have been carried out. Chemical analysis of the adsorbent revealed SiO₂ to be its major component. Kinetic data of adsorption was fitted by Lagergreen’s model and kad, the rate constant of adsorption, was found be maximum 2.69×10⁻² min⁻¹ at 25 °C with minimum at 35 °C. Values of coefficients of intra-particle diffusion and mass transfer have been determined at different values of temperature. Langmuir’s model has been used for equilibrium studies and the constants have been calculated. The studies conducted show the process of Cr(VI) removal to be exothermic in nature.

Keywords: Cr(VI), Sand, Removal, Kinetics, Equilibrium, Adsorption

? Unob, F., Wongsiri, B., Phaeon, N., Puanngam, M. and Shiowatana, J. (2007), Reuse of waste silica as adsorbent for metal removal by iron oxide modification. Journal of Hazardous Materials, 142 (1-2), 455-462.

Full Text: 2007\J Haz Mat142, 455.pdf

Abstract: Silica gel is widely used in research laboratories, especially for the purification of organic compounds. Consequently, waste silica gel is generated in increasing amounts. In this work, waste silica was modified by coating its surface with iron oxide aiming to obtain an effective adsorbent for metal removal from wastewater. In the preparation of the adsorbent, the optimal pretreatment temperature and iron concentration were investigated. The coated waste silica was characterized for BET surface area, pore size, specific pore volume and iron content. Iron oxide-coated waste silica was tested for the adsorption of Pb(II), Cu(II), Cd(II) and Ni(II) from solutions in a batch system. The effect of contact time, pH and salt concentration on metal adsorption was investigated. It was found that the adsorption of metals occurred rapidly and reached equilibrium within 30 min. The pH suitable for metal adsorption was between 6 and 7 and leaching of iron from the coating was observed only at pH 3 or lower. The presence of salt reduced the adsorption efficiency of the adsorbent. The adsorption behavior followed both Langmuir and Freundlich isotherms (25 °C). Finally, the efficacy of the adsorbents was investigated using aqueous lab waste where removal efficiencies ranging from 62 to 89% were achieved when the initial metal concentrations ranged from 13 to 42 mg L⁻¹.

Keywords: Waste Silica Gel, Iron Oxide, Metals, Adsorption

? Wang, X.S., Huang, J., Hu, H.Q., Wang, J. and Qin, Y. (2007), Determination of kinetic and equilibrium parameters of the batch adsorption of Ni(II) from aqueous solutions by Na-mordenite. Journal of Hazardous Materials, 142 (1-2), 468-476.

Full Text: 2007\J Haz Mat142, 468.pdf

Abstract: The potential to remove nickel(II) ions from aqueous solutions using Na-mordenite, a common zeolite mineral, was thoroughly investigated. The effects of relevant parameters solution pH, adsorbent dose, ionic strength, and temperature on nickel(II) adsorption capacity were examined. The sorption data followed the Langmuir, Freundlich, Langmuir–Freundlich and Dubinin–Radushkevich (D–R) isotherms. The maximum sorption capacity was found to be 5.324 mg/g at pH 6, initial concentration of 40 mg/L and temperature of 20 °C. Thermodynamic parameters, viz. changes in standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) have also been evaluated and the results show that the sorption process was spontaneous and endothermic in nature. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion were calculated. The activation energy (E_a) was found to be 12.465 kJ/mol in the present study, indicating a chemical sorption process involving weak interactions between sorbent and sorbate. The sorption capacity increased with the increase of solution pH and the decrease of ionic strength and adsorbent dose. The nickel(II) ions sorption by the Na-mordenite is not completely attributable to ion exchange. Compared to the other adsorbents, the nickel(II) ions show a lower affinity towards the clay mineral adsorbents.

Keywords: Activation, Activation Energy, Adsorbent, Adsorbent Dose, Adsorbents, Adsorption, Adsorption Capacity, Aqueous Solutions, Batch, Batch Adsorption, Biosorbents, Capacity, Changes, Chemical, Clay, Clay Mineral, Cobalt, Concentration, Copper, Data, Diffusion, Endothermic, Energy, Enthalpy, Entropy, Equilibrium, Freundlich, Ion Exchange, Ion-Exchange, Ionic Strength, Isotherms, Kaolinite, Kinetic, Langmuir, Langmuir-Freundlich, Mechanisms, Metal-Ions, Na-Mordenite, Ni(II), Nickel, Nickel(II), pH, Potential, Rate Constant, Removal, Rights, Solution, Solutions, Sorbate, Sorbent, Sorption, Sorption Capacity, Sorption Mechanism, Sorption Process, Standard, Strength, Temperature, Thermodynamic, Thermodynamic Parameters, Wastewater Treatment, Zeolite, Zeolites

? Liu, Z.S. (2007), Control of heavy metals during incineration using activated carbon fibers. Journal of Hazardous Materials, 142 (1-2), 506-511.

Full Text: 2007\J Haz Mat142, 506.pdf

Abstract: Activated carbon fibers (ACFs) were applied to control heavy metals in incineration flue gas. Three heavy metal species (Cr, Cd and Pb), three ACFs, various adsorption temperatures (150, 250 and 300 °C) and weights of ACFs were experimentally determined. The results indicated that the effects of the type of ACF and the weight of the ACFs on the solid-state Cr removal were insignificant. The extent of solid-state Cd and Pb removal was related to the knitting structure of ACFs and the physical characteristic of the metals. The removal efficiencies of the solid-state and gaseous metals at various reaction temperature followed the order 250 > 150 > 300 °C and 300 > 250 > 150 °C, respectively.

Keywords: Activated Carbon Fibers (ACFs), Adsorption, Condensation, Heavy Metals, Incineration

? Kumar, K.V. (2007), Pseudo-second order models for the adsorption of safranin onto activated carbon: Comparison of linear and non-linear regression methods. Journal of Hazardous Materials, 142 (1-2), 564-567.

Full Text: 2007\J Haz Mat142, 564.pdf

Abstract: Kinetic experiments were carried out for the sorption of safranin onto activated carbon particles. The kinetic data were fitted to pseudo-second order model of Ho, Sobkowsk and Czerwinski, Blanchard et al. and Ritchie by linear and non-linear regression methods. Non-linear method was found to be a better way of obtaining the parameters involved in the second order rate kinetic expressions. Both linear and non-linear regression showed that the Sobkowsk and Czerwinski and Ritchie’s pseudo-second order models were the same. Non-linear regression analysis showed that both Blanchard et al. and Ho have similar ideas on the pseudo-second order model but with different assumptions. The best fit of experimental data in Ho’s pseudo-second order expression by linear and non-linear regression method showed that Ho pseudo-second order model was a better kinetic expression when compared to other pseudo-second order kinetic expressions.

Keywords: Activated Carbon, Adsorption, Analysis, Assumptions, Carbon, Data, Experimental, Experiments, Expression, Kinetic, Kinetics, Linear Regression, Methods, Model, Models, Non-Linear, Non-Linear Method, Non-Linear Regression, Nonlinear Regression, Particles, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-Second Order, Pseudo-Second Order Kinetics, Pseudo-Second Order Model, Pseudo-Second-Order, Regression, Regression Analysis, Removal, Safranin, Second Order, Second-Order, Sorption

? Cestari, A.R., Vieira, E.F.S., de Oliveira, I.A. and Bruns, R.E. (2007), The removal of Cu(II) and Co(II) from aqueous solutions using cross-linked chitosan—Evaluation by the factorial design methodology. Journal of Hazardous Materials, 143 (1-2), 8-16.

Full Text: 2007\J Haz Mat143, 8.pdf

Abstract: A 2³ factorial design was employed to evaluate the quantitative removal of Cu(II) and Co(II) on glutaraldehyde-cross-linked chitosan from kinetic isotherms, using chitosan masses of 100 and 300 mg and temperatures of 25 and 35°C. The adsorption parameters were analyzed statistically using modeling polynomial equations and a cumulative normal probability plot. The results indicated the higher quantitative preference of the chitosan for Cu(II) in relation to Co(II). Increasing the chitosan mass decreases the adsorption/mass ratio (mol g⁻¹) for both metals. The principal effect of the temperature did not show statistical importance. The adsorption thermodynamic parameters, namely Δ_adsH, Δ_adsG and Δ_adsS, were determined. Exothermic and endothermic results were found in relation to a specific factorial design experiment. A comparison of Δ_adsH values was made in relation to some metal–adsorbent interactions in literature. It is suggested that the adsorption thermodynamic parameters are determined by the influence of the principal and interactive experimental parameters and not by the temperature changes alone.

Keywords: Activated Carbon, Adsorption, Adsorption Thermodynamics, Adsorption-Kinetics, Anionic Dyes, Aqueous Solutions, Changes, Chemometrics, Chitosan, Co(II), Comparison, Copper, Cross-Linked, Cross-Linked Chitosan, Crosslinked Chitosan, Cu(II), Cumulative, Design, Endothermic, Equilibrium, Evaluation, Exothermic, Experiment, Experimental, Heavy-Metal Ions, Influence, Interactions, Isotherms, Kinetic, Literature, Mass, Membranes, Metals, Methodology, Modeling, Normal, Preference, Removal, Removal of Metals, Rights, Silica-Gel, Solutions, Statistical, Temperature, Thermodynamic, Thermodynamic Data, Thermodynamic Parameters, Values, Waste-Water

? El-Dessouky, S.I., El-Sofany, E.A. and Daoud, J.A. (2007), Studies on the sorption of praseodymium(III), holmium(III) and cobalt(II) from nitrate medium using TVEX–PHOR resin. Journal of Hazardous Materials, 143 (1-2), 17-23.

Full Text: 2007\J Haz Mat143, 17.pdf

Abstract: The use of TVEX–PHOR resin for the sorption of praseodymium(III), holmium(III) and cobalt(II) from nitrate medium was carried out using batch and column techniques. Various parameters affecting the uptake of these metal ions such as v/m ratio, pH and the metal ion concentration were separately studied. Effect of temperature on the equilibrium distribution values has been studied to evaluate the changes in standard thermodynamic quantities. Experimental results of the investigated metal ions were found to fit to Freundlich isotherm model over the entire studied concentration range. Selectivity sequence of the resin for these metals is Ho > Pr > Co. The recovery of the investigated metals from the loaded resin is preformed with 0.1 M sulphuric acid.

Keywords: Aqueous-Solution, Batch, Changes, Co, Cobalt, Cobalt(II), Column, Concentration, Distribution, Equilibrium, Freundlich, Freundlich Isotherm, Holmium(III), Ion, Isotherm, Isotherm Model, Ligands, Loaded Resin, Metal, Metal Ions, Metals, Model, Nitrate, Nitrate Medium, pH, Praseodymium(III), Rare-Earth Elements, Recovery, Resin, Rights, Samples, Separation, Sorption, Standard, Sulphuric Acid, Techniques, Temperature, Thermodynamic, TVEX-PHOR Resin, Uptake

? Kumar, P.A., Ray, M. and Chakraborty, S. (2007), Hexavalent chromium removal from wastewater using aniline formaldehyde condensate coated silica gel. Journal of Hazardous Materials, 143 (1-2), 24-32.

Full Text: 2007\J Haz Mat143, 24.pdf

Abstract: A resinous polymer, aniline formaldehyde condensate (AFC) coated on silica gel was used as an adsorbent in batch system for removal of hexavalent chromium from aqueous solution by considering the effects of various parameters like reaction pH, dose of AFC coated silica gel, initial Cr(VI) concentration and aniline to formaldehyde ratio in AFC synthesis. The optimum pH for total chromium [Cr(VI) and Cr(III)] adsorption was observed as 3. Total chromium adsorption was second order and equilibrium was achieved within 90–120 min. Aniline to formaldehyde ratio of 1.6:1 during AFC synthesis was ideal for chromium removal. Total chromium adsorption followed Freundlich’s isotherm with adsorption capacity of 65 mg/g at initial Cr(VI) 200 mg/L. Total chromium removal was explained as combinations of electrostatic attraction of acid chromate ion by protonated AFC, reduction of Cr(VI) to Cr(III) and bond formation of Cr(III) with nitrogen atom of AFC. Almost 40–84% of adsorbed chromium was recovered during desorption by NaOH, EDTA and mineral acids. AFC coated silica gel can be effectively used for treatment of chromium containing wastewaters as an alternative.

Keywords: Total Chromium Adsorption, Hexavalent Chromium Removal, Amine Group, Resinous Polymer, Second Order Kinetics

? Moon, Y.H., Kim, J.G., Ahn, J.S., Lee, G.H. and Moon, H.S. (2007), Phosphate removal using sludge from fuller’s earth production. Journal of Hazardous Materials, 143 (1-2), 41-48.

Full Text: 2007\J Haz Mat143, 41.pdf

Abstract: This study assesses the phosphate removal capacity and mechanism of precipitation or adsorption from aqueous solutions in batch experiments by an industrial sludge containing gypsum (CaSO₄·2H₂O) obtained as a by-product from a fuller’s earth process.

The potential capacity for phosphate removal was tested using various solution concentrations, pH values, reaction times, and amount of sludge. The maximum phosphate adsorption capacity calculated using the Langmuir equation was 2.0 g kg⁻¹. The pH for the maximum adsorption by the sludge was neutral to alkaline (pH 7–12). Over 99% of phosphate was removed from a phosphate solution of 30 mg L⁻¹ using 0.15 g of sludge in a 9-h reaction.

Sulfate (SO₄²⁻) concentration increased with increasing initial phosphate concentration, possibly because of dissolution of gypsum and adsorption of both sulfate and phosphate. At high phosphate concentration (>1000 mg L⁻¹), relative constant concentration of Ca²⁺ was not consistent with adsorption of the most important phosphate removal mechanism. Results suggest that precipitation of calcium phosphate is principally responsible for phosphate removal under its high concentration. Agglomerated precipitate in the reaction sludge was observed by SEM and identified as brushite (CaHPO₄·2H₂O) by XRD, FT-IR, and DTA. Based on thermodynamic considerations, it is suggested that the brushite will readily transform to more stable phases, such as hydroxyapatite (Ca₅(PO₄)₃·OH).

Keywords: Adsorption, Brushite, Hydroxyapatite, Gypsum, Precipitation

? Tang, D.Y., Zheng, Z., Lin, K., Luan, J.F. and Zhang, J.B. (2007), Adsorption of p-nitrophenol from aqueous solutions onto activated carbon fiber. Journal of Hazardous Materials, 143 (1-2), 49-56.

Full Text: 2007\J Haz Mat143, 49.pdf

Abstract: The adsorption of p-nitrophenol (PNP) onto activated carbon fiber (ACF) was investigated in simulated wastewater in a batch system to evaluate the effects of solution pH, presence of sodium chloride, adsorbent doses and temperature. It was found that PNP adsorption amount depended on pH, sodium chloride content, adsorbent doses and temperature. Langmuir and Freundlich models were applied to describe the adsorption isotherms. Freundlich model agreed with experimental data well, indicating the possibility of more than just one monomolecular layer of coverage. SEM photographs of ACF before and after adsorption revealed that it was in part with multimolecular layers of coverage on ACF surfaces. The change of free energy, enthalpy, and entropy of adsorption were also evaluated for the adsorption process. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The experimental data fitted very well the pseudo-second-order kinetic model. Attempts were made to desorb PNP from ACF using dilute NaOH solution and water, and desorption efficiency was obtained to the extent of 92.7% with 0.025 M NaOH and water at 368 K.

Keywords: Adsorption, p-Nitrophenol (PNP), Activated Carbon Fiber (ACF), Desorption

? Malferrari, D., Brigatti, M.F., Laurora, A., Pini, S. and Medici, L. (2007), Sorption kinetics and chemical forms of Cd(II) sorbed by thiol-functionalized 2:1 clay minerals. Journal of Hazardous Materials, 143 (1-2), 73-81.

Full Text: 2007\J Haz Mat143, 73.pdf

Abstract: The interaction between Cd(II) in aqueous solution and two 2:1 expandable clay minerals (i.e., montmorillonite and vermiculite), showing different layer charge, was addressed via batch sorption experiments on powdered clay minerals both untreated and amino acid (cysteine) treated. Reaction products were characterized via X-ray powder diffraction (XRDP), chemical analysis (elemental analysis and atomic absorption spectrophotometry), thermal analysis combined with evolved gasses mass spectrometry (TGA-MSEGA) and synchrotron-based X-ray absorption spectroscopy via extended X-ray absorption fine structure (EXAFS) characterization. Sorption isotherms for Cd(II) in presence of different substrates, shows that Cd(II) uptake depends both on Cd(II) starting concentration and the nature of the substrate. Thermal decomposition of Cd–cysteine treated clay minerals evidences the evolution of H₂O, H₂S, NO₂, SO₂, and N₂O₃. These results are well consistent with XRDP data collected both at room and at increasing temperature and further stress the influence of the substrate, in particular cysteine, on the interlayer. EXAFS studies suggest that Cd(II) coordinates with oxygen atoms, to give monomer complexes or CdO molecules, either on the mineral surface and/or in the interlayer. For Cd–cysteine complexes EXAFS data agree with the existence of Cd–S clusters, thus suggesting a predominant role of the thiol group in the bonding of Cd with the amino acid.

Keywords: Montmorillonite, Vermiculite, Cd(II), Cysteine, Adsorption

? Bayramoğlu, G. and Arıca, M.Y. (2007), Biosorption of benzidine based textile dyes “Direct Blue 1 and Direct Red 128” using native and heat-treated biomass of Trametes versicolor. Journal of Hazardous Materials, 143 (1-2), 135-143.

Full Text: 2007\J Haz Mat143, 135.pdf

Abstract: The capacities and mechanisms of native and heat-treated white rot fungus “Trametes versicolor” biomass in removing of two different benzidine based dyes (i.e., Direct Blue 1, DB-1 and Direct Red 128, DR-128) from aqueous solution was investigated with different parameters, such as molecular weight of dye, adsorbent dosage, pH, temperature and ionic strength. In the batch system, the biosorption equilibrium time for both dyes was about 6 h. The maximum biosorption was observed at pH 6.0 for DB-1 and at pH 3.0 for DR-128 on the native and heat-treated fungal biomass. The biosorption capacities of the native and heat-treated fungal biomass (at 800 mg/L dye concentration) were found to be 101.1 and 152.3 mg/g for DB-1 and these were 189.7 and 225.4 mg dye/g biomass for DR-128, respectively. The Freundlih and Temkin adsorption isotherm models were used for the mathematical description of the biosorption equilibrium. The Freundlich and Temkin models were able to describe the biosorption equilibrium of DB-l and DR-128 on the native and heat-treated fungal preparations. The Freundlich model also showed that the small molecular weight dye (i.e., DR-128) had a higher affinity of adsorption that than of the higher molecular weight dye (i.e., DB-1). The dye biosorption on the fungal biomass preparations followed the second order kinetics model.

Keywords: Trametes Versicolor, Biosorption, Heat-Treatment, Benzidine Based Dye, Kinetics, Adsorption Isotherm Models

? Daneshvar, N., Khataee, A.R., Rasoulifard, M.H. and Pourhassan, M. (2007), Biodegradation of dye solution containing Malachite Green: Optimization of effective parameters using Taguchi method. Journal of Hazardous Materials, 143 (1-2), 214-219.

Full Text: 2007\J Haz Mat143, 214.pdf

Abstract: In this paper, optimization of biological decolorization of synthetic dye solution containing Malachite Green was investigated. The effect of temperature, initial pH of the solution, type of algae, dye concentration and time of the reaction was studied and optimized using Taguchi method. Sixteen experiments were required to study the effect of parameters on biodegradation of the dye. Each of experiments was repeated three times to calculate signal, noise (S, N). Our results showed that initial pH of the solution was the most effective parameter in comparison with others and the basic pH was favorable. In this study, we also optimized the experimental parameters and chose the best condition by determination effective factors. Based on the S, N ratio, the optimized conditions for dye removal were temperature 25C, initial pH 10, dye concentration 5 ppm, algae type Chlorella and time 2.5 h. The stability and efficiency of Chlorella sp. in long-term repetitive operations were also examined.

Keywords: Algae, Biodegradation, Biological, Comparison, Concentration, Decolorization, Determination, Dye, Dye Removal, Efficiency, Experimental, Experiments, Long Term, Long-Term, Malachite Green, Malachite-Green, Optimization, pH, Removal, Solution, Stability, Taguchi Method, Temperature

? Deng, L.P., Su, Y.Y., Su, H., Wang, X.T. and Zhu, X.B. (2007), Sorption and desorption of lead(II) from wastewater by green algae Cladophora fascicularis. Journal of Hazardous Materials, 143 (1-2), 220-225.

Full Text: 2007\J Haz Mat143, 220.pdf

Abstract: Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298 K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na₂EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, C=O and C–O could combine intensively with Pb(II).

Keywords: Biosorption, Lead(II), Cladophora fascicularis, Wastewater, Desorption

? Eren, Z. and Acar, F.N. (2007), Equilibrium and kinetic mechanism for Reactive Black 5 sorption onto high lime Soma fly ash. Journal of Hazardous Materials, 143 (1-2), 226-232.

Full Text: 2007\J Haz Mat143, 226.pdf

Abstract: Batch adsorption studies were carried out for the sorption of C.I. Reactive Black 5, a reactive dye, onto high lime fly ash, obtained from Soma Thermal Power Plant (Turkey), to be low cost adsorbent. The effect of various experimental parameters such as contact time, adsorbent dose and initial dye concentration were investigated. Determination of the adsorption equilibrium concentrations was determined by UV–vis spectrophotometry analytical method. Equilibrium data were fitted to the Freundlich and Langmuir isotherm equations and the equilibrium data were found to be well represented by the Freundlich isotherm equation. The adsorption kinetics of C.I. Reactive Black 5 onto high lime fly ash were also studied to characterize of the surface complexation reaction. A pseudo-second-order mechanism has been developed to predict the rate constant of the adsorption, the equilibrium capacity and initial adsorption rate with the effect of initial concentration. A single-stage batch adsorber design of the adsorption of C.I. Reactive Black 5 onto high lime fly ash has been studied based on the Freundlich isotherm equation.

Keywords: Adsorbent, Adsorbent Dose, Adsorption, Adsorption Equilibrium, Adsorption Isotherms, Adsorption Kinetics, Adsorption Rate, Batch, Batch Adsorber Design, Batch Adsorption, Capacity, Complexation, Concentration, Cost, Data, Design, Dye, Equilibrium, Experimental, Fly Ash, Freundlich, Freundlich Isotherm, High Lime Fly Ash, Intraparticle Diffusion, Isotherm, Isotherm Equations, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, Lime, Low Cost Adsorbent, Mechanism, Pseudo Second Order, Pseudo-First-Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Rate Constant, Reactive Black 5, Reactive Dye, Sorption, Spectrophotometry, Surface, Surface Complexation, Turkey

? Yu, J.X., Tong, M., Sun, X.M. and Li, B.H. (2007), Cystine-modified biomass for Cd(II) and Pb(II) biosorption. Journal of Hazardous Materials, 143 (1-2), 277-284.

Full Text: 2007\J Haz Mat143, 277.pdf

Abstract: The surface of dried biomass of baker’s yeast was modified by crosslinking cystine with glutaraldehyde. X-ray photoelectron spectroscopy and microscope were used to characterize the modified biomass. The adsorption capacity of the modified biomass for Cd²⁺ and Pb²⁺ showed an increase compared with the pristine biomass due to the presence of cystine on the biomass surface. Experimental data showed that the adsorption of the two metal ions increased with time until equilibrium was achieved. The adsorption capacities for Cd²⁺ and Pb²⁺ were 11.63 and 45.87 mg g⁻¹, respectively, which were determined from the Langmuir isotherm. The loaded biosorbent was regenerated using HCl solution and could be used repeatedly at six times with little loss of uptake capacity. FTIR spectroscopy revealed that carboxyl, amide, and hydroxyl groups on the biomass surface were involved in the adsorption of Cd²⁺ and Pb²⁺.

Keywords: Baker’s Yeast, Cystine, Glutaraldehyde, Crosslinking, Adsorption

? Ma, W., Ya, F.Q., Han, M. and Wang, R. (2007), Characteristics of equilibrium, kinetics studies for adsorption of fluoride on magnetic-chitosan particle. Journal of Hazardous Materials,