Personal Research Database

Full Text: 2007\J Haz Mat146, 428.pdf

Abstract: This letter reports the way to solve the Redlich–Peterson isotherm. In addition the importance of constraints for the Redlich–Peterson isotherm exponent was discussed in detail.

Keywords: Activated Carbon, Aqueous Solution, Biosorption, Copper(II), Isotherm, Kinetic, Kinetic Studies, Langmuir, Limitations, Nonlinear Method, Redlich-Peterson, Rights, Solution, Sorption Isotherm Parameters, Theory

? Sharma, Y.C. and Weng, C.H. (2007), Corrigendum to “Removal of chromium(VI) from water and wastewater by using riverbed sand: Kinetic and equilibrium studies” [J. Hazard. Mater. 142 (2007) 449–454]. Journal of Hazardous Materials, 146 (1-2), 435.

Full Text: 2007\J Haz Mat146, 435.pdf

? Strataki, N., Bekiari, V. and Lianos, P. (2007), Study of the conditions affecting dye adsorption on titania films and of their effect on dye photodegradation rates. Journal of Hazardous Materials, 146 (3), 514-519.

Full Text: 2007\J Haz Mat146, 514.pdf

Abstract: Nanocrystalline titania films have been deposited on glass slides by the sol-gel technique in the presence of surfactant, which plays the role of template of the nanostructure. Several different dyes, both anionic and cationic, have been adsorbed on these films from aqueous solutions. Some of these dyes were adsorbed at large quantities some at lower quantities. Some of them were adsorbed in monomeric form and others formed aggregates. Aggregates are easily distinguished by absorption spectrophotometry, since absorption of light is observed at a different wavelength than monomer absorption in a dilute solution. In all cases, aggregation demonstrated a hypsochromic shift, indicating repulsive interactions, which are justified in view of the fact that titania surface is charged and that adsorbed molecules are aligned in parallel. The above titania films are hydroxylated. Therefore, cationic dyes were readily adsorbed. Anionic dyes could be adsorbed only from aqueous solutions brought at low pH. Photodegradation rates of adsorbed dyes were generally fast since these films are efficient photocatalysts. Nevertheless, photodegradation of an adsorbed dye was faster when the quantity of the dye was smaller. When the adsorbed dyes formed aggregates, aggregation had adverse effect on photodegradation rates.

Keywords: Absorption, Adsorption, Aggregates, Aggregation, Aqueous Solutions, Cationic Dyes, Dye, Dye Adsorption, Dyes, Glass, Nanocrystalline Titania Films, pH, Photodegradation, Rates, Role, Sol-Gel, Solution, Solutions, Spectrophotometry, Surface, Surfactant, Template

? El-Khaiary, M.I. (2007), Kinetics and mechanism of adsorption of methylene blue from aqueous solution by nitric-acid treated water-hyacinth. Journal of Hazardous Materials, 147 (1-2), 28-36.

Full Text: 2007\J Haz Mat147, 28.pdf

Abstract: Kinetics adsorption experiments were conducted to evaluate the adsorption characteristics of a cationic dye (methylene blue, MB) onto nitric-acid treated water-hyacinth (N-WH). Results showed that N-WH can remove MB effectively from aqueous solution. The loading of MB onto N-WH was found to increase significantly with increasing the initial MB concentration, but the residual concentration of MB in solution also increased. A complete removal of MB from solution was only achieved at the lower range of initial MB concentration (less than 286 mg/L). Temperature had a slight effect on the amount adsorbed at equilibrium. The adsorption rate was fast and more than half of the adsorbed-MB was removed in the first 15 min at room temperature, which makes the process practical for industrial application. The adsorption kinetics at room temperature could be expressed by the pseudo second order model, while at higher temperatures (45-80C) and low MB concentration (97 mg/L) both Lagergren’s model and the pseudo second order model can be used to predict the kinetics of adsorption. The overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, then gradually changed to intraparticle diffusion control at a later stage. The initial period where external mass transfer is the rate controlling step was found to increase with increasing initial MB concentration and decrease with increasing temperature. The increase in temperature was also found to increase the rate of adsorption and reduce the time required to reach equilibrium. The initial rate of adsorption, h., was calculated, it was found to increase with increasing temperature, while the increase in MB concentration decreased h. at the lower concentration range then increased h. again at high concentration. The value of the activation coefficient, E, was found to be 8.207 kJ/mol, which indicates a diffusion controlled process. (c) 2007 Published by Elsevier B.V.

Keywords: Activation, Adsorption, Adsorption Characteristics, Adsorption Kinetics, Adsorption Rate, Aqueous Solution, Basic-Dyes, Biosorption, Biosorption, Cationic Dye, Characteristics, Concentration, Control, Diffusion, Diffusion Control, Dye, Equilibrium, External Mass Transfer, Industrial, Intraparticle Diffusion, Kinetics, Kinetics of Adsorption, Loading, Low, Mass Transfer, Mass-Transfer, MB, Mechanism, Methylene Blue, Model, Nitric Acid, Order, Predict, Process, Pseudo Second Order, Pseudo-Second-Order, Range, Rate, Removal, Room Temperature, Second Order, Temperature, Temperatures, Time, Transfer, Uptake, Waste, Water Hyacinth, Water-Hyacinth

? Ok, Y.S., Yang, J.E., Zhang, Y.S., Kim, S.J. and Chung, D.Y. (2007), Heavy metal adsorption by a formulated zeolite-Portland cement mixture. Journal of Hazardous Materials, 147 (1-2), 91-96.

Full Text: 2007\J Haz Mat147, 91.pdf

Abstract: Large amounts of fine zeolite by-product were produced when natural zeolite was processed into a powder with a specific particle size. In Korea, large piles of this by-product exist with no disposal options. We conducted studies to determine whether mixtures of this by-product with other materials could be used as a substitute to activated carbon for wastewater treatment. A granular material was formulated by mixing zeolite by-product with Portland cement (ZeoAds), and this material was tested for its efficiency for heavy metal removal from aqueous solutions. The ZeoAds removed pH and Cu in an aqueous solution up to 27.03 and 23.25 mg g(-1), respectively. Adsorption kinetics of the ZeoAds for heavy metals was first-order, and the ZeoAds removed about 90% of the Cu within 30 min. At solution pH lower than five, the adsorption specificity of the ZeoAds for metals was pH > Cu > Cd > Zn. Langmuir isotherms adequately described the adsorption, and adsorption capacity increased as the particle size decreased to 2 mm in diameter. The maximum adsorption capacities of the metals for the ZeoAds were, irrespective of the kinds of metals, about two times greater than those of activated carbon. Column experiments demonstrated that the ZeoAds was more efficient and had a higher sorptive capacity than activated carbon for removing metals from industrial wastewater. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Kinetics, Aqueous Solution, Capacity, Column, Cu, Exchange, First Order, Heavy Metal, Heavy Metal Adsorption, Heavy Metals, Industrial Wastewater, Ions, Isotherms, Kinetics, Langmuir, Langmuir Isotherms, Lead, Metal, Metals, Natural, Natural Zeolite, Natural Zeolites, pH, Portland Cement, Removal, Rhizopus-Arrhizus Biomass, Specificity, Treatment, Wastewater, Wastewater Treatment, Water, Zeolite

? Vilar, V.J.P., Botelho, C.M.S. and Boaventura, R.A.R. (2007), Methylene blue adsorption by algal biomass based materials: Biosorbents characterization and process behaviour. Journal of Hazardous Materials, 147 (1-2), 120-132.

Full Text: 2007\J Haz Mat147, 120.pdf

Abstract: Dead algal biomass is a natural material that serves as a basis for developing a new family of sorbent materials potentially suitable for many industrial applications. In this work an algal industrial waste from agar extraction process, algae Gelidium and a composite material obtained by immobilization of the algal waste with polyacrylonitrile (PAN) were physical characterized and used as biosorbents for dyes removal using methylene blue as model. The apparent and real densities and the porosity of biosorbents particles were determined by mercury porosimetry and helium picnometry. The methylene blue adsorption in the liquid phase was the method chosen to calculate the specific surface area of biosorbent particles as it seems to reproduce better the surface area accessible to metal ions in the biosorption process than the N₂ adsorption-desorption dry method. The porous texture of the biosorbents particles was also studied. Equilibrium isotherms are well described by the Langmuir equation, giving maximum uptake capacities of 171, 104 and 74 mg g^-1, respectively for algae, algal waste and composite material. Kinetic experiments at different initial methylene blue concentrations were performed to evaluate the equilibrium time and the importance of the driving force to overcome mass transfer resistances. The pseudo-first-order and pseudo-second-order kinetic models adequately describe the kinetic data. The biosorbents used in this work proved to be promising materials for removing methylene blue from aqueous solutions. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption-Desorption, Agar, Algae, Algal Biomass, Algal Waste, Applications, Aqueous Solutions, Aqueous-Solutions, Basic-Dyes, Biomass, Biosorbent, Biosorbents, Biosorption, Characterization, Composite, Composite Material, Concentrations, Densities, Driving, Dyes, Equilibrium, Equilibrium Time, Extraction, Family, Gelidium, Immobilization, Importance, Industrial, Industrial Waste, Isotherms, Kinetic, Kinetic Models, Kinetics, Langmuir, Langmuir Equation, Liquid Phase, Mass Transfer, Mass-Transfer, Materials, Mechanism, Mercury, Metal, Metal Ions, Methylene Blue, Methylene Blue Adsorption, Model, Models, N₂, N₂, Natural, Pan, Particles, Physical, Physical Properties, Porosimetry, Porosity, Porous, Process, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-First-Order, Pseudo-Second-Order, Removal, Solutions, Sorbent, Sorption, Specific Surface, Specific Surface Area, Surface, Surface Area, Surface-Area, Texture, Time, Transfer, Uptake, Waste

? Farré, M.J., Doménech, X. and Peral, J. (2007), Combined photo-Fenton and biological treatment for Diuron and Linuron removal from water containing humic acid. Journal of Hazardous Materials, 147 (1-2), 167-174.

Full Text: 2007\J Haz Mat147, 167.pdf

Abstract: A combined chemical (photo-Fenton) and biological treatment has been proposed for Diuron and Linuron degradation in water containing natural dissolved organic matter (DOM). Humic acid (HA) was used to simulate the DOM. During the photo-Fenton process ([Fe(II)] = 15.9 mg L^-1, [H₂O₂]=202 mgL^-1, 60min of UVA irradiation time), the chemical oxygen demand (COD), total organic carbon (TOC), toxicity (EC5015) and biodegradability (BOD₅/COD) of the generated intermediates were assessed. A reduction of photo-Fenton efficiency was observed when HA was present in solution. This effect has been explained as the result of a UVA light screening as well as a OH center dot radical quenching process by the HA. After the photo-Fenton process, the initial toxic and non-biodegradable herbicides were transformed into intermediates suitable for a subsequent aerobic biological treatment that was performed in a sequencing batch reactor (SBR). Complete elimination of the intermediates in presence of HA was reached at the end of the chemical-biological coupled system. Biosorption of HA onto the aerobic biomass was characterized. The results indicate that the Freundlich model adequately describes the adsorption of HA, a phenomena that follows a pseudo second-order adsorption kinetic model. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid, Adsorption, Adsorption Kinetic, Advanced Oxidation Processes, Aerobic, Aerobic Biological Treatment, Batch, Batch Reactor, Biodegradability, Biological Treatment, Biomass, Biosorption, BOD₅, COD, Carbon, Chemical, Chemical Oxygen Demand, Cod, Degradation, Demand, Dissolved, Dissolved Organic Matter, Diuron, Dom, Efficiency, Elimination, Freundlich, Freundlich Model, HA, Herbicides, Humic, Humic Acid, Hydrogen-Peroxide, Irradiation, Kinetic, Kinetic Model, Light, Matter, Model, Natural, OH, Organic, Organic Carbon, Organic Matter, Oxygen, Oxygen Demand, Ozonation, Photo-Fenton, Photocatalysis, Process, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Quenching, Radical, Reactor, Reduction, Removal, Reutilization, Sbr, Screening, Second Order, Sequencing Batch Reactor, Sequencing Batch Reactor, Sorption, System, Time, TOC, Total Organic Carbon, Toxic, Toxicity, Treatment, UVA, Waste-Water, Water

? Demir, A., and Arisoy, M. (2007), Biological and chemical removal of Cr(VI) from waste water: Cost and benefit analysis. Journal of Hazardous Materials, 147 (1-2), 275-280.

Full Text: 2007\J Haz Mat147, 275.pdf

Abstract: The objective of the present study is cost and benefit analysis of biological and chemical removal of hexavalent chromium [Cr(VI)] ions. Cost and benefit analysis were done with refer to two separate studies on removal of Cr(VI), one of heavy metals with a crucial role concerning increase in environmental pollution and disturbance of ecological balance, through biological adsorption and chemical ion-exchange.

Methods of biological and chemical removal were compared with regard to their cost and percentage in chrome removal. According to the result of the comparison, cost per unit in chemical removal was calculated €0.24 and the ratio of chrome removal was 99.68%, whereas those of biological removal were €0.14 and 59.3%. Therefore, it was seen that cost per unit in chemical removal and chrome removal ratio were higher than those of biological removal method. In the current study where chrome removal is seen as immeasurable benefit in terms of human health and the environment, percentages of chrome removal were taken as measurable benefit and cost per unit of the chemicals as measurable cost.

Keywords: Cost and benefit analysis, Heavy metal, Chrome, Adsorption, Ion-exchange

? Karagozoglu, B., Tasdemir, M., Demirbaş, E. and Kobya, M. (2007), The adsorption of basic dye (Astrazon Blue FGRL) from aqueous solutions onto sepiolite, fly ash and apricot shell activated carbon: Kinetic and equilibrium studies. Journal of Hazardous Materials, 147 (1-2), 297-306.

Full Text: 2007\J Haz Mat147, 297.pdf

Abstract: In this study, sepiolite, fly ash and apricot stone activated carbon (ASAC) were used as adsorbents for the investigation of the adsorption kinetics, isotherms and thermodynamic parameters of the basic dye (Astrazon Blue FGRL) from aqueous solutions at various concentrations (100-300 mg/L), adsorbent doses (3-12 g/L) and temperatures (303-323 K). The result showed that the adsorption capacity of the dye increased with increasing initial dye concentration, adsorbent dose and temperature. Three kinetic models, the pseudo-first-order, second-order, intraparticle diffusion, were used to predict the adsorption rate constants. The kinetics of adsorption of the basic dye followed pseudo-second-order kinetics. Equations were developed using the pseudo-second-order model which predicts the amount of the basic dye adsorbed at any contact time, initial dye concentration and adsorbent dose within the given range accurately. The adsorption equilibrium data obeyed Langmuir isotherm. The adsorption capacities (Q(0)) calculated from the Langmuir isotherm were 181.5 mg/g for ASAC, 155.5 mg/g for sepiolite and 128.2 mg/g for fly ash at 303 K. Thermodynamical parameters were also evaluated for the dye-adsorbent systems and revealed that the adsorption process was endothermic in nature. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption Capacities, Adsorption Capacity, Adsorption Equilibrium, Adsorption Equilibrium Data, Adsorption Isotherms, Adsorption Kinetics, Adsorption Process, Adsorption Rate, Aqueous Solutions, Ash, Basic Dye, Capacity, Carbon, Concentration, Concentrations, Constants, Contact Time, Diffusion, Dye, Endothermic, Equilibrium, Equilibrium Data, Equilibrium Studies, Fly Ash, Fly-Ash, Intraparticle Diffusion, Investigation, Ions, Isotherm, Isotherms, Kinetic, Kinetic Models, Kinetics, Kinetics of Adsorption, Langmuir, Langmuir Isotherm, Langmuir-Isotherm, Low-Cost Adsorbents, Model, Models, Parameters, Peat, Pith, Predict, Process, Product, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-First-Order, Pseudo-First-Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Pseudo-Second-Order Model, Range, Rate, Rate Constants, Removal, Second Order, Sepiolite, Shell, Solutions, Sorption, Stone, Temperature, Temperatures, Thermodynamic, Thermodynamic Parameters, Time, Unburned Carbon, Waste-Water

? Li, Q., Yue, Q.Y., Su, Y., Gao, B.Y. and Fu, L. (2007), Cationic polyelectrolyte/bentonite prepared by ultrasonic technique and its use as adsorbent for Reactive Blue K-GL dye. Journal of Hazardous Materials, 147 (1-2), 370-380.

Full Text: 2007\J Haz Mat147, 370.pdf

Abstract: In this study, the cationic polyelectrolyte polyepicholorohydrin-dimethylamine (EPI-DMA) was intercalated into bentonite using ultrasonic. The structure of EPI-DMA/bentonite and its adsorption of Reactive Blue K-GL (RB K-GL) dye were investigated. Compared with raw bentonite, the EPI-DMA/bentonite had larger interlayer spacing and was more hydrophobic, providing with better surface properties for adsorption. The adsorption of RB K-GL on EPI-DMA/bentonite was described by the adsorption models of Langmuir, Freundlich and Dubinin-Radushkevic. The adsorption kinetics was analyzed using pseudo-first- and second-order kinetic models and intraparticle, diffusion model. Results showed that both the intraparticle diffusion and first-order adsorption occur in the initial period of adsorption, and that pseudo-second-order kinetic model was more suitable for describing the whole adsorption process. The reaction rates were also calculated. The changes of free energy, enthalpy and entropy of adsorption were evaluated for the adsorption of RB K-GL onto EPI-DMA/bentonite, suggesting that the adsorption process was spontaneous and exothermic. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid Dyes, Activated Carbon, Adsorbent, Adsorption, Adsorption Kinetics, Adsorption Models, Adsorption Process, Adsorption Thermodynamics, Aqueous-Solution, Bentonite, Bleaching Earth, Cationic Polyelectrolyte, Cationic Polyelectrolyte, Bentonite, Diffusion, Diffusion Model, Disperse Dyes, Dye, Energy, Enthalpy, Entropy, Exothermic, First Order, Free Energy, Freundlich, Hydrophobic, Interlayer, Intraparticle Diffusion, Kinetic, Kinetic Model, Kinetic Models, Kinetics, Langmuir, Model, Models, Organic Pollutants, Polyelectrolyte, Process, Properties, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Reaction, Reaction Rates, Reactive Dye, Second Order, Sorption, Spontaneous, Structure, Surface, Surface Properties, Thermodynamics, Ultrasonic, Waste-Water

? Hamdaoui, O. and Naffrechoux, E. (2007), Modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon - Part I. Two-parameter models and equations allowing determination of thermodynamic parameters. Journal of Hazardous Materials, 147 (1-2), 381-394.

Full Text: 2007\J Haz Mat147, 381.pdf

Abstract: The adsorption equilibrium isotherms of five phenolic compounds from aqueous solutions onto granular activated carbon (GAC) were studied and modeled. Phenol (Ph), 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP), and 2,4,6-trichlorophenol (TCP) were chosen for the adsorption tests. To predict the adsorption isotherms and to determine the characteristic parameters for process design, seven isotherm models: Langmuir (five linear forms), Freundlich, Elovich, Temkin, Fowler-Guggenheim, Kiselev, and Hill-de Boer models were applied to experimental data. The results reveal that the adsorption isotherm models fitted the data in the order: Fowler-Guggenheim > Hill-de Boer > Temkin > Freundlich > Kiselev > Langmuir isotherms. Adsorption isotherms modeling shows that the interaction of phenolic compounds with activated carbon surface is localized monolayer adsorption, that is adsorbed molecules are adsorbed at definite, localized sites. Each site can accommodate only one molecule. The interaction among adsorbed molecules is repulsive and there is no association between them, adsorption is carried out on energetically different sites and is an exothermic process. Uptake of phenols increases in the order pH < 2-CP < 4-CP < DCP < TCP, which correlates well with respective increase in molecular weight, cross-sectional area, and hydrophobicity and decrease in solubility and pK(a). Additionally, for the four tested chlorophenols, it seems that the magnitude of adsorption is directly proportional to their degree of chlorination. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Modeling, Adsorption, Isotherms, Phenol, Chlorophenols, GAC, Dilute Aqueous-Solutions, P-Chlorophenol, Desorption, Kinetics, Sorption, Temperature, Equilibrium, Pollutants, Ultrasound, Mechanism

? Hamdaoui, O. and Naffrechoux, E. (2007), Modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon - Part II. Models with more than two parameters. Journal of Hazardous Materials, 147 (1-2), 401-411.

Full Text: 2007\J Haz Mat147, 401.pdf

Abstract: The adsorption equilibrium isotherms of five phenolic compounds, phenol, 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, from aqueous solutions onto granular activated carbon were studied and modeled. In order to determine the best-fit isotherm, the experimental equilibrium data were analyzed using thirteen adsorption isotherm models with more than two-parameter; nine three-parameter equations - the Redlich-Peterson, Sips, Langmuir-Freundlich, Fritz-Schlunder, Radke-Prasnitz (three models), Toth, and Jossens isotherms - three four-parameter equation - the Weber-van Vliet, Fritz-Schlunder, and Baudu isotherms - and one five-parameter equation - the Fritz-Schlunder isotherm. The results reveal that the adsorption isotherm models fitted the experimental data in the order: Baudu (four-parameter)>Langmuir-Freundlich (three-parameter) >Sips (three-parameter) >Fritz-Schlunder (five-parameter)>Toth (three-parameter) > Fritz-Schlunder (four-parameter)>Redlich-Peterson (three-parameter). The influence of solution pH on the adsorption isotherms of 4-CP was investigated. It was shown that the solution pH has not an effect on the adsorption isotherms for pH

Keywords: Modeling, Adsorption, Isotherms, Phenol, Chlorophenols, GAC, Dilute Aqueous-Solutions, Organic Solutes, Desorption, Temperature

? Kocaoba, S. (2007), Comparison of Amberlite IR 120 and dolomite’s performances for removal of heavy metals. Journal of Hazardous Materials, 147 (1-2), 488-496.

Full Text: 2007\J Haz Mat147, 488.pdf

Abstract: The presence of heavy metals in the environment is major concern due to their toxicity. Contamination of heavy metals in water supplies has steadily increased over the last years as a result of over population and expansion of industrial activities.

A strong cation-exchange resin, Amberlite IR 120 and a natural zeolite, dolomite were used for the removal of Lead(II) and cadmium(II). The optimum conditions were determined in a batch system as concentration range was between 5 and 100 mg/L, pH range between 1 and 8, contact time between 5 and 90 min, and the amount of adsorbent was from 0. 1 to 1 g. A constant stirring speed, 2000 rpm, was chosen during all of the experiments. The optimum conditions were found to be a concentration of 20 mg/L, pH of 5, contact time of 60 min and 0.5 g of adsorbent.

Also, for investigation of exchange equilibria different amounts of ion exchange resin and dolomite were contacted with a fixed volume and concentration of a heavy metal bearing solutions. Sorption data have been interpreted in terms of Langmuir and Freundlich equations.

The effect of adsorption temperature on the heavy metals adsorption onto dolomite was investigated at three different temperatures (20, 40 and 60C). Thermodynamic parameters were calculated.

The results obtained show that the Amberlite IR 120 strong cation-exchange resin and dolomite performed well for the removal of these heavy metals. As a low cost adsorbent, dolomite can preferable for removal of heavy metals from wastewaters. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Lead(II), Cadmium(II), Ion Exchange Resin, Dolomite, Adsorption, Conservative Technologies, Aqueous-Solutions, Ion-Exchange, Natural Clinoptilolite, Synthetic Resin, Adsorption, Pb(II), Bentonite, Cd(II), Zn(II), Waste

? Arrigo, I., Catalfamo, P., Cavallari, L. and Di Pasquale, S. (2007), Use of zeolitized pumice waste as a water softening agent. Journal of Hazardous Materials,