Personal Research Database

Full Text: 2006\J Haz Mat137, 1377.pdf

Abstract: The potential use of the brown seaweed, Ecklonia, biomass as a bioreductant for reducing Cr(VI) was examined in a continuous packed-bed column. The effects of the operating parameters, such as influent Cr(VI) concentration, influent pH, biomass concentration, flow rate and temperature, on the Cr(VI) reduction were investigated. Increases in the influent Cr(VI) concentration and flow rate or a decrease in the biomass concentration inside the column led to a higher breakthrough of the Cr(VI) ions in the effluent. Particularly, the influent pH and temperature most significantly affected on the breakthrough curve of Cr(VI); a decrease in the influent pH or an increase in the temperature enhanced the Cr(VI) reduction in the column. For process application, a non-parametric model using neural network was used to predict the breakthrough curves of the column. Finally, the potential of the column packed with Ecklonia biomass for Cr(VI) detoxification was demonstrated.

Keywords: Hexavalent Chromium, Detoxification, Ecklonia, Column, Neural Network

? Marañón, E., Ulmanu, M., Fernández, Y., Anger, I. and Castrillón, L. (2006), Removal of ammonium from aqueous solutions with volcanic tuff. Journal of Hazardous Materials, 137 (3), 1402-1409.

Full Text: 2006\J Haz Mat137, 1402.pdf

Abstract: This paper presents kinetic and equilibrium data concerning ammonium ion uptake from aqueous solutions using Romanian volcanic tuff. The influence of contact time, pH, ammonium concentration, presence of other cations and anion species is discussed. Equilibrium isotherms adequately fit the Langmuir and Freundlich models. The results showed a contact time of 3 h to be sufficient to reach equilibrium and pH of 7 to be the optimum value. Adsorption capacities of 19 mg NH₄⁺/g were obtained in multicomponent solutions (containing NH₄⁺, Zn²⁺, Cd²⁺, Ca²⁺, Na²⁺). The presence of Zn and Cd at low concentrations did not decrease the ammonium adsorption capacity. Comparison of Romanian volcanic tuff with synthetic zeolites used for ammonium removal (5A, 13X and ZSM-5) was carried out. The removal efficiciency of ammonium by volcanic tuff were similar to those of zeolites 5A and 13X at low initial ammonium concentration, and much higher than those of zeolite ZSM-5.

Keywords: Zeolites, Volcanic Tuff, Ammonium Removal, Adsorption Kinetic, Adsorption Equilibrium

? Gylienė, O., Nivinskienė, O. and Razmutė, I. (2006), Copper(II)–EDTA sorption onto chitosan and its regeneration applying electrolysis. Journal of Hazardous Materials, 137 (3), 1430-1437.

Full Text: 2006\J Haz Mat137, 1430.pdf

Abstract: Cu(II)–EDTA (ethylendiaminetetraacetate) complexes are widely used in the manufacture of printed circuit boards. In order to avoid the outlet into the environment the sorption of complexes onto chitosan is proposed. The uptake of both Cu(II) and EDTA proceeds in weakly acidic (pH 3–5) and strongly alkaline (pH > 12) solutions. In acidic solutions EDTA sorption prevails. FT-IR investigations have shown that in acidic solutions the amide bonds between –COOH groups of EDTA and –NH₂ groups of chitosan were formed. In alkaline solutions the single EDTA sorption does not proceed. In this media the sorption is enhanced by Cu(II) ions. The possible sorption mechanisms are discussed.

The uptake of both Cu(II) and EDTA by chitosan depends on the ratio between them in solutions. EDTA sorption in acidic solutions increases with increase in its concentration while that of Cu(II) decreases. In alkaline solutions the sorption of both Cu(II) and EDTA increases with increase in Cu(II) concentration.

The use of electrolysis enables to regenerate chitosan and to reuse it. During electrolysis copper is deposited onto the cathode and EDTA is oxidized onto the anode. The current efficiency depends on the current intensity, the load of chitosan and the pH of the background electrolyte. Electrolysis under the most favorable conditions ensures the 10-cycles regeneration without considerable changes in the sorption properties of chitosan. FT-IR spectra of the initial and regenerated chitosans are similar.

Keywords: EDTA, Cu(II), Sorption, Chitosan, Regeneration

? Pełech, R., Milchert, E. and Wróbel, R. (2006), Adsorption dynamics of chlorinated hydrocarbons from multi-component aqueous solution onto activated carbon. Journal of Hazardous Materials, 137 (3), 1479-1487.

Full Text: 2006\J Haz Mat137, 1479.pdf

Abstract: The results and a numerical simulation of studies on dynamics of the adsorption from seven-component aqueous solution of light chlorinated hydrocarbons on activated carbon have been presented. Aqueous solution of 1,2-dichloroethane (12DCE), 1,1,2,2-tetrachloroethane (S-TET), chloroform (CHCl₃), carbon tetrachloride (CCl₄), 1,1-dichloroethene (VDC), perchloroethene (PER) and 1,1,2-trichloroethene (TRI) was used. Concentrations of chlorohydrocarbons were similar as in wastewater from vinyl chloride plant. A cell model that incorporates the diffusion through a laminar layer of liquid around a particle was used to describe the experimental results. The applied calculation methods, which take kinetics into account, allows to well describe a phenomenon of dynamic adsorption. Mean relative deviations between the experimental and calculated values amounted 17%. The breakthrough curves become steeper along with an increase of the bed height. A consistency of the experimental results with those calculated indicates for a negligible contribution of the axial diffusion on the dynamic adsorption process of light chlorinated hydrocarbons from aqueous solution under the hydrodynamic conditions corresponding to the Reynolds number equal to 1.3. Determined optimal bed height for waste linear flow rate—15 cm/min is in the range 80–120 cm.

Keywords: Activated carbon, Adsorption, Chlorohydrocarbons, Diffusion, Wastewater

? Kumar, K.V. (2006), Linear and non-linear regression analysis for the sorption kinetics of Methylene blue onto activated carbon. Journal of Hazardous Materials, 137 (3), 1538-1544.

Full Text: 2006\J Haz Mat137, 1538.pdf

Abstract: Batch kinetic experiments were carried out for the sorption of methylene blue onto activated carbon. The experimental kinetics were fitted to the pseudo first-order and pseudo second-order kinetics by linear and a non-linear method. The five different types of Ho pseudo second-order expression have been discussed. A comparison of linear least-squares method and a trial and error non-linear method of estimating the pseudo second-order rate kinetic parameters were examined. The sorption process was found to follow a both pseudo first-order kinetic and pseudo second-order kinetic model. Present investigation showed that it is inappropriate to use a type 1 and type pseudo second-order expressions as proposed by Ho and Blanachard et al. respectively for predicting the kinetic rate constants and the initial sorption rate for the studied system. Three correct possible alternate linear expressions (type 2 to type 4) to better predict the initial sorption rate and kinetic rate constants for the studied system (methylene blue/activated carbon) was proposed. Linear method was found to check only the hypothesis instead of verifying the kinetic model. Non-linear regression method was found to be the more appropriate method to determine the rate kinetic parameters.

Keywords: Activated Carbon, Adsorption, Adsorption, Adsorption Kinetics, Analysis, Basic-Dyes, Carbon, Comparison, Error, Experimental, Experiments, Expression, First Order, Fly-Ash, Investigation, Kinetic, Kinetic Model, Kinetic Parameters, Kinetics, Linear Method, Metal-Ions, Methylene Blue, Model, Non-Linear, Non-Linear Method, Non-Linear Regression, Nonlinear Regression, Parameters, Peat, Process, Pseudo, Pseudo First Order, Pseudo First-Order, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo Second Order Kinetics, Pseudo Second-Order, Pseudo-First-Order, Pseudo-Second-Order, Rate Constants, Regression, Regression Analysis, Removal, Rights, Safranin, Second Order, Second Order Kinetics, Second-Order, Second-Order Kinetics, Sorption, Sorption Kinetics, Sorption Process, Trial, Water

? Mohan, D. and Chander, S. (2006), Removal and recovery of metal ions from acid mine drainage using lignite: A low cost sorbent. Journal of Hazardous Materials, 137 (3), 1545-1553.

Full Text: 2006\J Haz Mat137, 1545.pdf

Abstract: Acid mine drainage (AMD), has long been a significant environmental problem resulting from the microbial oxidation of iron pyrite in presence of water and air, affording an acidic solution that contains toxic metal ions. The main objective of this study was to remove and recover metal ions from acid mine drainage (AMD) by using lignite, a low cost sorbent. Lignite has been characterized and used for the AMD treatment. Sorption of ferrous, ferric, manganese, zinc and calcium in multi-component aqueous systems was investigated. Studies were performed at different pH to find optimum pH. To simulate industrial conditions for acid mine wastewater treatment, all the studies were performed using single and multi-columns setup in down flow mode. The empty bed contact time (EBCT) model was used for minimizing the sorbent usage. Recovery of the metal ions as well as regeneration of sorbent was achieved successfully using 0.1 M nitric acid without dismantling the columns.

Keywords: Adsorption, Heavy Metals, Adsorbent, Lignite, Acid Mine Drainage Treatment, Solid Waste Utilization, Ferrous, Ferric, Manganese

? Han, R.P., Li, H.K., Li, Y.H., Zhang, J.H., Xiao, H.J. and Shi, J. (2006), Biosorption of copper and lead ions by waste beer yeast. Journal of Hazardous Materials, 137 (3), 1569-1576.

Full Text: 2006\J Haz Mat137, 1569.pdf

Abstract: Locally available waste beer yeast, a byproduct of brewing industry, was found to be a low cost and promising adsorbent for adsorbing copper and lead ions from wastewater. In this work, biosorption of copper and lead ions on waste beer yeast was investigated in batch mode. The equilibrium adsorptive quantity was determined to be a function of the solution pH, contact time, beer yeast concentration, salt concentration and initial concentration of copper and lead ions. The experimental results were fitted well to the Langmuir and Freundlich model isotherms. According to the parameters of Langmuir isotherm, the maximum biosorption capacities of copper and lead ions onto beer yeast were 0.0228 and 0.0277 mmol g⁻¹ at 293 K, respectively. The negative values of the standard free energy change (ΔG°) indicate spontaneous nature of the process. Competitive biosorption of two metal ions was investigated in terms of sorption quantity. The amount of one metal ion adsorbed onto unit weight of biosorbent (q_e) decreased with increasing the competing metal ion concentration. The binding capacity for lead is more than for copper. Ion exchange is probably one of the main mechanism during adsorptive process.

Keywords: Waste Beer Yeast, Biosorption, Copper Ion, Lead Ion

? Chen, C.C., Lu, C.S., Mai, F.D. and Weng, C.S. (2006), Photooxidative N-de-ethylation of anionic triarylmethane dye (sulfan blue) in titanium dioxide dispersions under UV irradiation. Journal of Hazardous Materials, 137 (3), 1600-1607.

Full Text: 2006\J Haz Mat137, 1600.pdf

Abstract: The TiO₂-mediated photocatalysis process has been successfully applied to degradation of dye pollutants. Our results indicate that the TiO₂ surface is negatively charged, and the sulfan blue (SB) adsorbs onto the TiO₂ surface through the positive di-ethylamino groups while the TiO₂ surface is positively charged and the SB adsorbs onto the TiO₂ surface through the negative sulfonyl groups. In order to obtain a better understanding of the mechanistic details of this TiO₂-assisted photodegradation of the SB dye with UV irradiation, five intermediates of the processes were separated, identified, and characterized by the HPLC-ESI-MS technique, which included a positive- and negative-ion mode. The results indicated that the N-de-ethylation process continues until the N-de-ethylated SB dye is completely formed. The probable photodegradation pathways were proposed and discussed. The reaction mechanisms of UV, TiO₂ proposed in this study should be useful for future applications of the technology to the decolorization of dyes.

Keywords: Decolorization, Degradation, Dispersions, Dye, Dyes, Irradiation, Mechanisms, Mode, N-De-Ethylation, Pathways, Photocatalysis, Photodegradation, Pollutants, Sulfan Blue, Surface, Technology, TiO₂, Titanium, Titanium Dioxide, Triarylmethane, Understanding, UV, UV, TiO₂

? Lodeiro, P., Herrero, R. and Sastre de Vicente, M.E. (2006), Batch desorption studies and multiple sorption–regeneration cycles in a fixed-bed column for Cd(II) elimination by protonated Sargassum muticum. Journal of Hazardous Materials, 137 (3), 1649-1655.

Full Text: 2006\J Haz Mat137, 1649.pdf

Abstract: The protonated alga Sargassum muticum was employed in batch desorption studies to find the most appropriate eluting agent for Cd(II)-laden biomass regeneration. Eleven types of eluting solutions at different concentrations were tested, finding elution efficiencies higher than 90% for most of the desorbents studied. Total organic carbon and biomass weight loss measurements were made. The reusability of the protonated alga was also studied using a fixed-bed column. Eleven consecutive sorption–regeneration cycles at a flow rate of 10 mL min⁻¹ were carried out for the removal of 50 mg L⁻¹ Cd(II) solution. A 0.1 M HNO₃ solution was employed as desorbing agent. The column was operated during 605 h for sorption and 66 h for desorption, equivalent to a continuous use during 28 days, with no apparent loss of sorption performance. In these cycles, no diminution of the breakthrough time was found; although, a relative loss of sorption capacity, regarding the found in the first cycle, was observed. The slope of the breakthrough curves experiments a gradual increase reaching its maximum value for the last cycle tested (40% greater than for the first one). The maximum Cd(II) concentration elution peak was achieved in 5 min or less, and the metal effluent concentration was always lower than 0.9 mg L⁻¹ after 1 h of elution. The maximum concentration factor was determined to be between 55 and 109.

Keywords: Sargassum muticum, Fixed-Bed Column, Cd(II), Sorption–Desorption

? Tokcaer, E. and Yetis, U. (2006), Pb(II) biosorption using anaerobically digested sludge. Journal of Hazardous Materials, 137 (3), 1674-1680.

Full Text: 2006\J Haz Mat137, 1674.pdf

Abstract: Removal of Pb(II) by using resting cells of anaerobically digested sludge (ADS) obtained from a nearby wastewater treatment plant was examined. Firstly, sorption kinetic and equilibrium experiments were conducted using agitated, thermostated (25 °C) batch reactors. The maximum Pb(II) sorption capacity was found to be very high (1750 mg/g dry ADS or 8.45 mmol/g dry ADS). At all initial Pb(II) concentrations tested, sorption resulted in neutralization with an increase in the solution pH from an initial value of 4.0–5.5 to an equilibrium value of 7.0–8.0, at which Pb(II) can precipitate as hydroxide. The removal of Pb(II) by ADS was found to involve bioprecipitation as well as biosorption. FTIR spectrometry highlighted carboxyl groups present on the surface of ADS as the major functional groups responsible for biosorption. Secondly, a three-stage semi-continuous pseudo-counter current reactor system was tested to reduce ADS requirement in comparison to a conventional single-stage batch reactor. At an initial Pb(II) concentration of about 200 mg/L, an effluent Pb(II) concentration of 1.3 mg/L was achieved in the three stage reactor, corresponding to a metal removal capacity of 682.7 mg/g dry ADS (3.30 mmol/g), in comparison to 1.9 mg/L and 644.0 mg/g dry ADS (3.10 mmol/g) for the single-stage batch reactor.

Keywords: Anaerobically Digested Sludge, Lead, Removal, Sorption, Wastewater

? Bayramoğlu, G., Çelik, G. and Arıca, M.Y. (2006), Biosorption of Reactive Blue 4 dye by native and treated fungus Phanerocheate chrysosporium: Batch and continuous flow system studies. Journal of Hazardous Materials, 137 (3), 1689-1697.

Full Text: 2006\J Haz Mat137, 1689.pdf

Abstract: The native and treated fungal biomass of Phanerocheate chrysosporium was used for the biosorption of a textile dye (i.e., Reactive Blue 4). In the batch system, the biosorption equilibrium time was about 4 h and the maximum dye uptake on all the tested fungal biomass preparations was observed at pH 3.0. The dye uptake capacities of the biosorbents at 600 mg L⁻¹ dye concentration were found to be 132.5, 156.9, 147.6 and 81.1 mg g⁻¹ for native and heat-, acid- and base-treated dry fungal preparations, respectively. The dye uptake capacity order of the fungal preparations was found as heat-treated > acid-treated > native > base-treated. The Langmuir, Freundlich and Temkin adsorption models were used for the mathematical description of the biosorption equilibrium. The Freundlich and Temkin models were able to describe the biosorption equilibrium of Reactive Blue 4 on native and treated fungal preparations. The dye biosorption on the fungal biomass preparations followed Ritchie kinetic model. Biosorption of the dye from aqueous solution was also investigated in a continuous flow system. The maximum biosorption capacity of the heat-treated fungal biomass P. chrysosporium was 211.6 mg (g dry biomass)⁻¹ at an initial dye concentration of 600 mg L⁻¹ and at a flow rate of 20 mL h⁻¹.

Keywords: Phanerocheate Chrysosporium, Dye Biosorption, Textile Dye, Reactive Blue 4, Kinetics, Adsorption Isotherm Model

? Lai, H.Y. and Chen, Z.S. (2006), The influence of EDTA application on the interactions of cadmium, zinc, and lead and their uptake of rainbow pink (Dianthus chinensis). Journal of Hazardous Materials, 137 (3), 1710-1718.

Full Text: 2006\J Haz Mat137, 1710.pdf

Abstract: Soil used in this study was artificially contaminated with Cd, Zn, Pb, or applied in combinations (Cd–Zn, Cd–Pb, Zn–Pb, or Cd–Zn–Pb) to study the interactions of metals in soil contaminated with multiple metals. After planting rainbow pink (Dianthus chinensis) in these soils for 21 days, three different concentrations of ethylenedinitrilotetraacetic acid (EDTA) solutions were added to study the effect of applying EDTA on the interactions among these metals. The concentrations of Cd, Zn, and Pb in the soil solutions of different metals-treated soils increased significantly after applying 5 mmol EDTA kg⁻¹ soil (p < 0.05). The potential of groundwater contamination will increase after applying EDTA and it is not recommended to be in situ used or have to use very carefully. The existence of Pb in the Cd-contaminated soil enhanced the uptake of Cd in rainbow pink in the treatments of control and 2 mmol EDTA kg⁻¹ soil. Cadmium inhibited the concentration of Zn without applying EDTA. However, whether the application of EDTA or not and the applied EDTA concentration had the greatest effect on the uptake of Pb when compared to Cd and Zn. After applying 5 mmol EDTA kg⁻¹ soil, Cd or Zn in the Pb-contaminated soil inhibited the uptake of Pb in rainbow pink, but there were no effect in other treatments.

Keywords: Rainbow Pink, Interaction, EDTA, Cd, Zn, Pb

? Önal, Y. (2006), Kinetics of adsorption of dyes from aqueous solution using activated carbon prepared from waste apricot. Journal of Hazardous Materials, 137 (3), 1719-1728.

Full Text: 2006\J Haz Mat137, 1719.pdf

Abstract: Adsorbent (WA11Zn5) has been prepared from waste apricot by chemical activation with ZnCl₂. Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N₂ adsorption and DFT plus software. Adsorption of three dyes, namely, Methylene Blue (MB), Malachite Green (MG), Crystal Violet (CV), onto activated carbon in aqueous solution was studied in a batch system with respect to contact time, temperature. The kinetics of adsorption of MB, MG and CV have been discussed using six kinetic models, i.e., the pseudo first order model, the pseudo second order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, the modified Freundlich equation. Kinetic parameters and correlation coefficients were determined. It was shown that the second order kinetic equation could describe the adsorption kinetics for three dyes. The dyes uptake process was found to be controlled by external mass transfer at earlier stages (before 5min) and by intraparticle diffusion at later stages (after 5min). Thermodynamic parameters, such as ∆G, ∆H and ∆S, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures and concentrations. The themodynamics of dyes-WAZn115 system indicates endothermic process.

Keywords: Activated Carbon, Activation, Adsorbent, Adsorption, Adsorption Kinetics, Aqueous Solution, Batch, Batch System, BET, BET Surface Area, Carbon, Chemical, Chemical Activation, Correlation, DFT, Diffusion, Diffusion Model, Distribution, Dye Removal, Dyes, Elovich, Elovich Equation, Endothermic, Equilibrium, Freundlich, Freundlich Equation, Intraparticle Diffusion, Intraparticle Diffusion Model, Kinetic, Kinetic Equation, Kinetic Models, Kinetic Parameters, Kinetics, Kinetics of Adsorption, Malachite Green, Mass Transfer, MB, Methylene Blue, Mg, Model, Models, Modified, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Second Order, Second-Order, Size, Software, Solution, Surface, Surface Area, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Uptake, Volume, Waste, ZnCl₂

? Sergios, K. Papageorgiou, S.K., Katsaros, F.K., Kouvelos, E.P., Nolan, J.W., Deit, H.L. and Kanellopoulos, N.K. (2006), Heavy metal sorption by calcium alginate beads from Laminaria digitata. Journal of Hazardous Materials, 137 (3), 1765-1772.

Full Text: 2006\J Haz Mat137, 1765.pdf

Abstract: Alginate with a high M/G ratio, extracted from Laminaria digitata, was evaluated for Cu²⁺, Cd²⁺ and Pb²⁺ sorption in acidic solutions, in the form of calcium cross-linked beads. The high M/G ratio of alginate extracted from this algal species is most likely the determining factor for the increased adsorption capacity of the investigated metals, indicating that the mannuronic acid is responsible for the ion exchange mechanism. The data obtained from the batch experiments have been interpreted with Langmuir, Freundlich and Sips models. The Sips equation provided the best fit with the experimental results, indicating sorption sites heterogeneity for the material. The pH was found to have a significant effect on the process, with sorption capacity reaching a maximum at pH 4.5, indicating a competition mechanism between H⁺ and metal ions.

Kinetic experiments were performed at the optimum pH. For the interpretation of the kinetic experiments the Linear Adsorption Model was employed and diffusion coefficients were determined. The model fits the experimental data at higher concentrations, where the adsorbed quantity remains almost constant. Finally, a simplified expression of the batch kinetic adsorption model was employed. The model, predicts adequately, not only the diffusivity values, but also the concentration profiles inside the spherical particles.

Keywords: Heavy Metals, Alginate Beads, Diffusion, Kinetics, Biosorption, M/G ratio

? Ho, Y.S. and Ofomaja, A.E. (2006), Kinetic studies of copper ion adsorption on palm kernel fibre. Journal of Hazardous Materials,