Personal Research Database

Full Text: 2008\J Haz Mat152, 662.pdf

Abstract: This study proposed an oil palm by-product as a low-cost adsorbent for the removal of hexavalent chromium [Cr(VI)] from aqueous solution. Adsorption of Cr(VI) by sulphuric acid and heat-treated oil palm fibre was conducted using batch tests. The influence of pH, contact time, initial chromium concentration and adsorbent dosage on the removal of Cr(VI) from the solutions was investigated. The optimum initial pH for maximum uptake of Cr(VI) from aqueous solution was found to be 1.5. The removal efficiency was found to correlate with the initial Cr(VI) concentration, adsorbent dosage as well as the contact time between Cr(VI) and the adsorbent. The adsorption kinetics tested with pseudo first order and pseudo second order models yielded high R² values from 0.9254 to 0.9870 and from 0.9936 to 0.9998, respectively. The analysis of variance (ANOVA) showed significant difference between the R² values of the two models at 99% confidence level. The Freundlich isotherm (R² = 0.8778) described Cr(VI) adsorption slightly better than the Langmuir isotherm (R² = 0.8715). Difficulty in desorption of Cr(VI) suggests the suitability of treated oil palm fibre as a single-use adsorbent for Cr(VI) removal from aqueous solution. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Adsorption Kinetics, Analysis, Anova, Aqueous Solution, Batch, Chromium, Chromium(VI), Concentration, Confidence, Desorption, Efficiency, First, First Order, Freundlich, Freundlich Isotherm, Hexavalent Chromium, Isotherm, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, Low Cost Adsorbent, Low-Cost Adsorbent, Models, pH, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Removal, Removal Efficiency, Second Order, Second-Order, Solution, Solutions, Sulphuric Acid, Treated Oil Palm Fibre, Uptake

? Yang, H., Xu, R., Xue, X.M., Li, F.T. and Li, G.T. (2008), Hybrid surfactant-templated mesoporous silica formed in ethanol and its application for heavy metal removal. Journal of Hazardous Materials, 152 (2), 690-698.

Full Text: 2008\J Haz Mat152, 690.pdf

Abstract: With cetyltrimethylammonium (CTAB) and tetramethylammonium hydroxide (TMAOH) as hybrid surfactant templates, a mesoporous adsorbent (adsorbent Q was synthesized in ethanol via the integration of “One-step” procedure and “Evaporation-Induced Self-Assembly” procedure. During the synthesis, TMAOH served as the subsidiary structure-directing agent. Adsorbent C exhibited higher pore diameter (centered at 6.1 ), BET surface area (421.9 m²/g) and pore volume (0.556 cm³/g) than the other two adsorbents only using P123 (adsorbent A) or CTAB (adsorbent B) as the surfactant. The adsorbents were also characterized by XRD and FTIR spectroscopy. The adsorption of copper, zinc, lead, iron, silver and manganese ions on adsorbent C was investigated by contrast tests with adsorbent A and B. The experimental data showed that adsorbent C possessed better adsorption properties than the counterparts. The order of adsorption capacity for six metal ions was Mn²⁺ < Zn²⁺ < Cu²⁺ < Fe²⁺ < Pb²⁺ < Ag⁺. The kinetic and thermodynamic properties and the regeneration capacity of adsorbent C were also discussed. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Mesoporous Silica, Heavy Metal Removal, Adsorbent, Tetramethylammonium Hydroxide, Evaporation-Induced Self-Assembly, Sulfonic-Acid Groups, Functionalized SBA-15, Selective Adsorption, Aqueous-Solution, Co-Condensation, Pore Structures, Methylene-Blue, Thin-Films, Ions, Separation

? Zubieta, C.E., Messina, P.V., Luengo, C., Dennehy, M., Pieroni, O. and Schulz, P.C. (2008), Reactive dyes remotion by porous TiO₂-chitosan materials. Journal of Hazardous Materials, 152 (2), 765-777.

Full Text: 2008\J Haz Mat152, 765.pdf

Abstract: In this work, the aim was to evaluate the remotion (adsorption plus degradation) of two reactive dyes, Methylene Blue (MB) and Benzopurpurin (BP), from aqueous solutions by the utilization of TiO₂-chitosan microporous materials.

Two different TiO₂-chitosan hybrid materials were synthesized: TiO₂-Chit A with 280mg chitosan/gTiO₂ and TiO₂-Chit B with 46.76mg chitosan/g TiO₂. Adsorption data obtained at different solution temperatures (25, 35, and 45C) revealed an irreversible adsorption that decrease with the increment of T. Langmuir, Freundlich and Sips isotherm equation were applied to the experimental data. The obtained parameters and correlation coefficient showed that the adsorption of both dyes on TiO₂-Chit A at the three work temperatures was best predicted by the Langmuir isotherm, while Sips equation adjusted better to adsorption data on TiO₂-Chit B.

The adsorption enthalpy was relatively high and varied with T, indicating that interaction between adsorbent and adsorbate molecules was not only physical but chemical. There is a change in the adsorption heat capacity, (Delta(ads) C-p < 0), related with intense hydrophobic interactions.

The kinetic adsorption data were processed by the application of Lagergren and Avrami models. It was found that adsorption of both dyes on both adsorbents under the operating conditions was best predicted by Avrami model. The variation of kinetic order, n, and k(av), with Tare related to a pore followed by intra particle diffusion control of the adsorption rate.

MB photodegraclation on both TiO₂-chitosan hybrid materials was of 91 (in A) and 41 % (in B) and augmented with the chitosan content. For BP can be seen that the process in darkness resulted in a high remotion capacity than in UV light presence. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Chitosan, TiO₂, Dye Remotion, Photodegradation, Pore Structure-Analysis, Phenomenological Theory, Aqueous-Solution, Humic-Acid, Metal-Ions, T-Method, Chitosan, Adsorption, Sorption, Water

? Özer, A., Gürbüz, G., Çalimli, A. and Körbahti, B.K. (2008), Investigation of nickel(II) biosorption on Enteromorpha prolifera: Optimization using response surface analysis. Journal of Hazardous Materials, 152 (2), 778-788.

Full Text: 2008\J Haz Mat152, 778.pdf

Abstract: In this study, the biosorption of nickel(II) ions on Enteromorpha prolifera, a green algae, was investigated in a batch system. The single and combined effects of operating parameters such as initial pH, temperature, initial metal ion concentration and biosorbent concentration on the biosorption of nickel(H) ions on E. prolifera were analyzed using response surface methodology (RSM). The optimum biosorption conditions were determined as initial pH 4.3, temperature 27C, biosorbent concentration 1.2 g/L and initial nickel(II) ion concentration 100 mg/L. At optimum biosorption conditions, the biosorption capacity of E. prolifera for nickel(II) ions was found to be 36.8 mg/g after 120 min biosorption. The Langmuix and Freundlich isotherm models were applied to the equilibrium data and defined very well both isotherm models. The monolayer coverage capacity of E. prolifera for nickel(II) ions was found as 65.7 mg/g. In order to examine the rate limiting step of nickel(II) biosorption, such as the mass transfer and chemical reaction kinetics, the intraparticle diffusion model, external diffusion model and the pseudo second order kinetic model were tested with the experimental data. It was found that for both contributes to the actual biosorption process. The pseudo second order kinetic model described the nickel(II) biosorption process with a good fitting. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Algae, Analysis, Batch, Batch System, Biosorbent, Biosorption, Capacity, Chemical, Concentration, Coverage, Data, Diffusion, Diffusion Model, Enteromorpha Prolifera, Equilibrium, Experimental, Freundlich, Freundlich Isotherm, Green Algae, Intraparticle Diffusion, Intraparticle Diffusion Model, Isotherm, Kinetic, Kinetic Model, Kinetics, Langmuir, Mass Transfer, Metal, Methodology, Model, Models, Monolayer, Nickel(II), Nickel(II) Ion, pH, Pseudo Second Order, Pseudo-Second-Order, Rate Limiting Step, Reaction Kinetics, Response Surface Methodology, Response Surface Methodology (RSM), Second Order, Second-Order, Surface, Temperature

? Tzou, Y.M., Wang, S.L., Liu, J.C., Huang, Y.Y. and Chen, J.H. (2008), Removal of 2,4,6-trichlorophenol from a solution by humic acids repeatedly extracted from a peat soil. Journal of Hazardous Materials, 152 (2), 812-819.

Full Text: 2008\J Haz Mat152, 812.pdf

Abstract: Humic acid (HA) is one of the major components of soil organic matter. It strongly affects the sorption behavior of organic and inorganic contaminants in soils. To obtain a better understanding of the interactions of contaminants with HA, a repeated extraction technique has been applied to a peat soil to obtain HA fractions with varying aliphaticity and aromaticity, which were subsequently correlated to the sorption properties of 2,4,6-trichlorophenol (TCP). HA fractions were extracted repeatedly using an alkaline solution and each HA fraction was separated into two portions with an air-drying or re-suspending (denoted as RSHAs) process. Solid-state (13)C NMR and elemental analysis demonstrated that the aromaticity and polarity of HAs decreased with extractions. Kinetic results indicated that air-dried HAs exhibited two-step first order sorption behavior with a rapid stage followed by a slower stage. The slower sorption is attributed to the diffusion of 2,4,6-TCP in the condensed aromatic domains of HAs. Conversely, sorption of 2,4,6-TCP on RSHAs was extremely rapid and could not be fitted with any kinetic model. For air-dried HAs the sorption capacity (K,) was weakly correlated with the chemical compositions of HAs. However, a positive trend between K, and aromaticity was observed for RSHAs. Compared with the results of air-dried HAs with their counterparts of RSHAs, it is therefore concluded that air-drying may alter the structure of HAs through artificially creating a more condensed domain in HAs. The structural alternation may result in an incorrect interpretation of the relationship between sorption capacity and chemical composition of HAs and a misjudgment of the transport behavior of 2,4,6-TCP in soils and sediments. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: 2,4,6-Trichlorophenol, Aliphaticity, Analysis, Aromaticity, Behavior, Binding, Capacity, Chlorophenols, Diffusion, First Order, Fractions, Humic Acid, Humic Acids, Interpretation, Kinetic, Kinetic Model, Linear Sorption, Model, Naphthalene, NMR, Nonlinear Sorption, Nonlinearity, Peat, Phenanthrene Sorption, Polarity, Removal, Sediment Organic-Matter, Sediments, Soil, Sorption, Sorption Isotherm, Substances, Trend, Water

? Smičiklas, I., Onjia, A., Raičević, S., Janaćković, Đ. and Mitrić, M. (2008), Factors influencing the removal of divalent cations by hydroxyapatite. Journal of Hazardous Materials, 152 (2), 876-884.

Full Text: 2008\J Haz Mat152, 876.pdf

Abstract: The effect of pH, contact time, initial metal concentration and presence of common competing cations, on hydroxyapatite (HAP) sorption properties towards Ph²⁺, Cd²⁺, Zn²⁺, and Sr²⁺ ions was studied and compared using a batch technique. The results strongly indicated the difference between the sorption mechanism of Pb²⁺ and other investigated cations: the removal of Pb²⁺ was pH-independent and almost complete in the entire pH range (3-12), while the sorption of Cd²⁺, Zn²⁺ and Sr²⁺ generally increased with an increase of pH; the contact time required for attaining equilibrium was 30 mm for Pb²⁺ versus 24h needed for other cations; maximum sorption capacity of HAP sample was found to be an order of magnitude higher for Pb²⁺ (3.263 mmol/g), than for Cd²⁺ (0.601 mmol/g), Zn²⁺ (0.574 mmol/g) and Sr²⁺ (0.257 mmol/g); the selectivity of HAP was found to decrease in the order Ph²⁺ > Cd²⁺ > Zn²⁺ > Sr²⁺ while a decrease of pH_pzc, in respect to the value obtained in inert electrolyte, followed the order Cd²⁺ > Zn²⁺ > Ph²⁺ > Sr²⁺; neither of investigated competing cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺) influenced Pb²⁺ immobilization whereas the sorption of other cations was reduced in the presence of Ca²⁺, in the order Sr²⁺ > Cd²⁺ > Zn ²⁺. The pseudo-second order kinetic model and Langmuir isotherm have been proposed for modeling kinetic and equilibrium data, respectively. The sorption of all examined metals was followed by Ca²⁺ release from the HAP crystal lattice and pH decrease. The ion exchange and specific cation sorption mechanisms were anticipated for Cd²⁺, Zn²⁺ and Sr²⁺, while dissolution of HAP followed by precipitation of hydroxypyromorphite (Pb₁₀(PO₄)₆(OH)₂) was found to be the main operating mechanism for Pb²⁺ immobilization by HAP, with the contribution of specific cation sorption. (c) 2007 Elsevier B. V. All rights reserved.

Keywords: Batch, Capacity, Cation, Cation Sorption, Cd²⁺, Concentration, Data, Dissolution, Equilibrium, Hydroxyapatite, Immobilization, Ion Exchange, Ion-Exchange, Isotherm, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Isotherm, Mechanism, Mechanisms, Metal, Metals, Model, Modeling, Na⁺, Pb²⁺, pH, pHpzc, Precipitation, Pseudo Second Order, Pseudo-Second Order, Pseudo-Second-Order, Release, Removal, Sorption, Sorption Capacity, Sorption Mechanism, Sorption Mechanisms, Value, Zn²⁺

? Kalmykova, Y., Stromvall, A.M. and Steenari, B.M. (2008), Adsorption of Cd, Cu, Ni, Pb and Zn on Sphagnum peat from solutions with low metal concentrations. Journal of Hazardous Materials, 152 (2), 885-891.

Full Text: 2008\J Haz Mat152, 885.pdf

Abstract: This work investigates adsorption of metal ions on Sphagnum peat from solutions with environmentally relevant concentrations of metals. The peat moss is intended as an alternative, low-cost filter material for contaminated waters. Adsorption of Cd, Cu, Ni, Pb and Zn was studied in batch tests, and adsorption isotherms were determined. The kinetics of adsorption was analyzed using a second-order model and rate constants were calculated. An empirical model for predicting adsorption of metal ions at a given time was derived from these constants. Metal ions were removed in the descending order Pb > Cu > Ni > Cd > Zn. Relationship between the affinities of the metals to the peat active sites with chemical properties for the metals were indicated by the results. In addition, equilibration studies were performed at constant pH and ionic strength. The experimental data fitted the Freundlich equation. Both the uptake of metals and the Freundlich constants increased in line with increasing pH. The Freundlich exponent declined with higher initial concentrations, suggesting adsorption to sites with lower activity. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherms, Alternative, Aqueous-Solution, Cd, Experimental, Freundlich, Freundlich Isotherm, Fulvic-Acid, Heavy Metals, Heavy-Metals, Humic Acids, Ion-Binding, Isotherms, Kinetics, Metal, Metal Ions, Metals, Model, Natural Organic-Matter, Pb, Peat, pH, Removal, Rights, Sorption, Sphagnum Peat, Substances, Waste-Water, Work

? Jain, R. and Sikarwar, S. (2008), Removal of hazardous dye congored from waste material. Journal of Hazardous Materials, 152 (3), 942-948.

Full Text: 2008\J Haz Mat152, 942.pdf

Abstract: The present paper is aimed to investigate and develop cheap adsorption methods for color removal from wastewater using waste material sawdust as adsorbent. Sawdust, a biosorbent, was successfully utilized in removing a water soluble azo, dye, congored from wastewater. The paper incorporates effect of pH, temperature, amount of adsorbent, contact time, concentration of adsorbate, particle size on adsorption. Specific rate constants of the processes were calculated by kinetic measurements and a first order adsorption kinetics was observed in each case. Langmuir and Freundlich adsorption isotherm models were then applied to calculate thermodynamics parameters as well as to suggest the plausible mechanism of the ongoing adsorption processes. In order to observe the quality of wastewater COD measurements were also carried out before and after the treatments. A significant decrease in the COD values was observed, which clearly indicates that adsorption method offer good potential to remove congored from wastewater. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Sawdust, Congored, Adsorption, Kinetics, Waste Material, Liquid-Phase Adsorption, Methylene-Blue, Activated Carbon, Aqueous-Solutions, Basic Dye, Reactive Dyes, Equilibrium, Kinetics, Water, Adsorbents

? Kuo, C.Y. (2008), Desorption and re-adsorption of carbon nanotubes: Comparisons of sodium hydroxide and microwave irradiation processes. Journal of Hazardous Materials, 152 (3), 949-954.

Full Text: 2008\J Haz Mat152, 949.pdf

Abstract: This study evaluates exhausted carbon nanotubes regenerated by desorption processes using 1mM NaOH and microwave irradiation processes. Kinetic analyses of re-adsorption were performed using pseudo first- and second-order models. Regression results revealed that a pseudo first-order model accurately captured re-adsorption kinetics. The regeneration efficiency was 28, 30, 35 and 44% at 18, 28, 38 and 48C using desorption agent of 1mM NaOH for 24 h, respectively. Microwave power was considered the most important factor in regeneration experiments, as the temperature reached by exhausted CNTs was directly related to microwave power in this study. Additionally, microwave regeneration was more effective than the desorption agent of NaOH. The most effective conditions for regenerating exhausted CNTs were a microwave power input of 1000 W for 20 min. (C) 2007 Published by Elsevier B.V.

Keywords: Analyses, Carbon, Carbon Nanotubes, Desorption, Efficiency, Experiments, First, First Order, First-Order Model, Kinetic, Kinetics, Microwave, Microwaves, Model, Models, Nanotubes, NaOH, Power, Pseudo First Order, Pseudo First-Order, Pseudo-First-Order, Re-Adsorption, Regeneration, Second Order, Second-Order, Sodium, Temperature

? Ayoob, S. and Gupta, A.K. (2008), Insights into isotherm making in the sorptive removal of fluoride from drinking water. Journal of Hazardous Materials, 152 (3), 976-985.

Full Text: 2008\J Haz Mat152, 976.pdf

Abstract: The defluoridation research has thrown up many technologies, with adsorption as a popular alternative, especially among fluoride endemic habitations of the developing world. In the endeavor to develop novel adsorbents for defluoridation, the adsorption potential of hardened alumina cement granules (ALC) were examined through isotherm fitting. Though the adsorbent showed enhanced adsorption capacity at higher fluoride concentration ranges, the errors associated with linearization in isotherm fitting were also found to be increasing. The propagation of these errors was more prominent in Dubinin-Radushkevich and Langmuir models but negligible in Freundlich. The chi(2) analysis, used to correlate the equilibrium experimental data and the isotherm models, also suggested poor correlations at higher fluoride concentration ranges for all the models. The procedure of linear and nonlinear regression through optimization of error functions rendered the ‘best-fit’ model and optimum model parameters, through sum of normalized error (SNE) values. Though ALC exhibited maximum monolayer adsorption capacity of 34.36 mg g^-1 in concentration variation studies of fluoride in the range of 2.5-100 mgl^-1 in synthetic water, it got reduced to 10.215 mg g^-1 in dose variation studies and further to 0.9358 mg g^-1 in natural ground water. Though Langmuir appeared as the best-fit model in terms of R 2 in synthetic studies of different fluoride concentrations, the procedure of linear and nonlinear regression demonstrated that Freundlich was the best-fit. The nonlinear X 2 analysis together with minimum SNE values convincingly demonstrated that the equilibrium studies with dose variations of ALC offers more reliable isotherm parameters than those with high fluoride concentrations. The sorption of fluoride by ALC appeared endothermic with Freundlich adsorption capacity parameter increased from 0.5589 to 0.99391 g^-1 in natural water and 3.980-7.5198 1 g^-1 in synthetic water systems for a rise in temperature from 290 to 3 10 K. The study deviates from conventional methodologies of relying solely on R 2 values in selecting ‘best-fit’ isotherm model, and basically demonstrates how the optimum model parameters like ‘adsorption capacity’ evolves through linear and nonlinear regression using error functions. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Defluoridation, Nonlinear Regression, Sorption, Basic Dye Adsorption, Aqueous-Solution, Component Systems, Activated Alumina, Equilibrium, Models, Single, Defluoridation, Chemistry, Oxides

? Singh, A., Kumar, D. and Gaur, J.P. (2008), Removal of Cu(II) and Pb(II) by Pithophora oedogonia: Sorption, desorption and repeated use of the biomass. Journal of Hazardous Materials, 152 (3), 1011-1019.

Full Text: 2008\J Haz Mat152, 1011.pdf

Abstract: Maximum sorption of Cu(II) and Pb(II) by dried filamentous green alga Pithophora oedogonia occurred at pH 4.5 and 5.0, respectively. Chemical pretreatment could not appreciably enhance the metal sorption ability of the biomass. HCl and EDTA desorbed 92-96% of the sorbed metal from the metal-loaded biomass. Sorption and desorption of both the test metals were very rapid attaining an equilibrium within 15 min. The time course data of both the processes fitted well to the pseudo-first and the pseudo-second-order Lagergren kinetic models with r(2) >= 0.979. The isotherm equilibrium of Cu(II) and Pb(II) followed the Redlich-Peterson and Sips model very well with r(2) >= 0.991. The sorption of Cu(II) and Pb(II) at varying biomass doses could be well defined by linear and hyperbolic decrease, respectively. The regenerated biomass of Pithophora has better reusability for Pb(II) than for Cu(II). A good mechanical strength of Pithophora biomass was apparent as only 10-15% loss of biomass occurred at the end of the fifth cycle. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Biomass, Copper(II), Course, Cu(II), Data, Desorption, Edta, Equilibrium, Green Alga, Isotherm, Kinetic, Kinetic Models, Lead(II), Metal, Metal Sorption, Metals, Model, Models, Pb(II), pH, Pithophora, Pretreatment, Pseudo Second Order, Pseudo-First and, Pseudo-Second-Order, Redlich-Peterson, Removal, Sorption, Sorption Isotherm, Sorption-Desorption Cycle, Strength

? Mohan, D., Singh, K.P. and Singh, V.K. (2008), Wastewater treatment using low cost activated carbons derived from agricultural byproducts: A case study. Journal of Hazardous Materials, 152 (3), 1045-1053.

Full Text: 2008\J Haz Mat152, 1045.pdf

Abstract: A variety of low cost activated carbons were developed from agricultural waste materials viz., coconut shell, coconut shell fibers and rice husk. The low cost activated carbons were fully characterized and utilized for the remediation of various pollutants viz., chemical oxygen demand (COD), heavy metals, anions, etc., from industrial wastewater. Sorption studies were carried out at different temperatures and particle sizes to study the effect of temperatures and surface areas. The removal of chloride and fluoride increased with rise in temperature while COD and metal ions removal decreased with increase in temperature, thereby, indicating the processes to be endothermic and exothermic, respectively. The kinetics of COD adsorption was also carried out at different temperatures to establish the sorption mechanism and to determine various kinetic parameters. The COD removal was 47-72% by coconut shell fiber carbon (ATFAC), 50-74% by coconut shell carbon (ATSAC) and 45-73% by rice husk carbon (ATRHC). Furthermore, COD removal kinetics by rice husk carbon, coconut shell carbon and coconut fiber carbon at different temperatures was approximately represented by a first order rate law. Results of this fundamental study demonstrate the effectiveness and feasibility of low cost activated carbons. The parameters obtained in this study can be fully utilized to establish fixed bed reactors on large scale to treat the contaminated water.

Keywords: Activated Carbons, Adsorption, Agricultural, Agricultural Waste, Anions, Carbon, Case Study, Chemical, Chemical Oxygen Demand, Chloride, Coconut Fiber, Coconut Shell, Coconut Shell Fibers, Coconut Shells, COD, COD Removal, Cost, Demand, Effectiveness, Endothermic, Exothermic, Feasibility, Fibers, First, First Order, Fixed Bed, Fluoride, Heavy Metals, Industrial Wastewater, Ions, Kinetic, Kinetic Parameters, Kinetics, Law, Low Cost, Mechanism, Metal, Metal Ions, Metal Ions Removal, Metals, Oxygen, Pollutants, Rate Law, Remediation, Removal, Rice, Rice Husk, Rice-Husk, Scale, Sorption, Sorption Mechanism, Surface, Surface Areas, Temperature, Treatment, Waste, Waste Materials, Wastewater, Wastewater Treatment, Water, Water, Wastewater Treatment

? Oliveira, W.E., Franca, A.S., Oliveira, L.S. and Rocha, S.D. (2008), Untreated coffee husks as biosorbents for the removal of heavy metals from aqueous solutions. Journal of Hazardous Materials,