Personal Research Database

Full Text: W\Wat Res35, 2341.pdf

Abstract: Rapid removal of disserved dilute lead (Pb) by pyroaurite-like compound MgxFey(OH)(2(x+y)) (CO₃^2-)(y/2). MH₂O; anionic clay: one of layered double hydroxides) from water was studied through batch and column experiments. The Pb-removal property of the compound was evaluated as a function of concentration of Pb in the treated solution, space Velocity (Sv) of the solution in the column packed with the compound, pH of the solution and contaminated humic substance. The compound showed a highly effective Pb-removal property that was comparable to the other conventional adsorbents. The Pb was removed rapidly by the column packed with the compound over the wide range of the Sv. The buffering pH function of the compound contributed to the Pb removal producing weak-alkali atmosphere. The contamination of humic substance in the treated solution reduced the Pb removal largely depending on its amount. The effectiveness of the compound for the rapid Pb removal was confirmed through a series of experiments. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Lead, Removal, Pyroaurite, Layered Double Hydroxide, Humic Substance, Adsorption, Ion-Exchange, Precipitation, Adsorption, Ions, Adsorbent, Cadmium, Carbon, Oxide, Iron

Chen, J.P. and Lin, M.S. (2001), Equilibrium and kinetics of metal ion adsorption onto a commercial H-type granular activated carbon: Experimental and modeling studies. Water Research, 35 (10), 2385-2394.

Full Text: W\Wat Res35, 2385.pdf

Abstract: Systematic studies on metal ion adsorption equilibrium and kinetics by a commercial H-type granular activated carbon were carried out. Titration of the carbon showed that the surface charge density decreased with an increasing pH. Higher copper adsorption was obtained with increasing solution pH and ionic strength. Metal removal was in the descending order: Cu²⁺ > Zn²⁺ approximate to Co²⁺. Copper removal was not affected by addition of zinc or cobalt, while copper can reduce both zinc and cobalt removal. Kinetic experiments demonstrated that the copper adsorption rapidly occurred in the first 30-60 min and reached the complete removal in 3-5 h. Removal of zinc and cobalt was slightly slower than that of copper. It was found that the mass transfer is important in the metal adsorption rate. The surface complex formation model was used successfully to describe the surface change density, as well as the single-and multi-species metal adsorption equilibrium. The copper removal was due to adsorption of Cu²⁺, CuOH⁺, and CuCl⁺, while the zinc and cobalt uptake was due to the formation of surface-metal complexes of SOM²⁺ and SOMOH⁺ (M = Zn and Co). It was found that the diffusion-control model well described the adsorption kinetics with various metal ions and pH values. Finally sensitivity analysis on the kinetic model’s parameters was carried out. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Single-and Multi-Species Metal Adsorption, H-Type Granular Activated Carbon, Equilibrium, Kinetics, Experimental, Modeling, Mercury(II), Copper(II), Lead(II), Removal, Water

Maine, M.A., Duarte, M.V. and Suñé, M.L. (2001), Cadmium uptake by floating macrophytes. Water Research, 35 (11), 2629-2634.

Full Text: W\Wat Res35, 2629.pdf

Abstract: Cd uptake capacity of a group of floating macrophytes (Salvinia herzogii. Pistia stratiotes. Hydromistia stolonifera and Eichhornia crassipes) was determined in outdoors experiments during the lowest temperature period of the year. Although all studied species were highly efficient in the Cd uptake. Pistia stratiotes was selected for further research because of its superior performance and its higher average relative growth rate. Cadmium% removal by Pistia stratiotes was greater in the first 24 h of the experiments (63.65, 72 and 74% of the added Cd for 1, 2. 4 and 6 mg Cd l^-1, respectively) After 31 days of growth. Pistia stratiotes efficiently removed Cd at the studied concentrations. The macrophyte was able to keep its capacity for Cd removal even though some toxicity symptoms appeared at 4 and 6 mg Cd l^-1. The greater the initial concentration, the greater Cd bioaccumulation rates, The increase of Cd concentration in plant tissues occurred especially in roots and was linearly related to the quantity of Cd added. Cd sorption by roots is faster than translocation to the plant aerial part and it occurs mainly during the first 24 h. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Cadmium Uptake, Macrophytes, Pistia Stratiotes, Roots, Water Pollution, Waste-Water Treatment, Nutrient Removal, Aquatic Plants, Heavy-Metals, Hyacinth, Environments, Toxicity, Wetlands

Huang, S.L. (2001), Cadmium adsorption by sediment in a turbulence tank. Water Research, 35 (11), 2635-2644.

Full Text: W\Wat Res35, 2635.pdf

Abstract: The mechanism of sediment motion that affects cadmium (Cd) adsorption on sediment particles was studied in a turbulence tank in the presence (and absence) of bed mud. The experimental results were verified by a mathematical model for heavy metal transport-transformation developed for the turbulence tank. The mathematical model includes the equations of water Row, sediment motion. heavy metal transport-transformation. heavy-metal reaction kinematics and equations for prescribing the initial conditions and boundary conditions for the experiment. The model conforms the transport transformation of heavy-metal pollutants in surface waters to following the law of convective-diffusive of common tracers and the characteristics of fare and transport of sediment motion. Variations of dissolved Cd concentrations and suspended particulate Cd concentrations with time and in the water column were measured and computed. The experimental measurements correspond with the computed results. Both the experimental measurements and computed results show that it takes about 6 h to reach equilibrium condition for cadmium adsorption by sediment particles. This is different from the result obtained from experiments conducted in continuously stirred tank reactors (or batch reactors) in which adsorption equilibrium can be achieved in about 20 min. Determination of the model parameters for sediment adsorption-desorption of metals in the tank is discussed. The experimental and computed results obtained in this study are useful to solve practical engineering problems in surface waters. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Water-Sediment-Pollutant Interaction, Turbulence Tank, Mathematical Modeling, Metal Transport-Transformation, Surface Waters, Fresh

Navarro, R.R., Tatsumi, K., Sumi, K. and Matsumura, M. (2001), Role of anions on heavy metal sorption of a cellulose modified with poly(glycidyl methacrylate) and polyethyleneimine. Water Research, 35 (11), 2724-2730.

Full Text: W\Wat Res35, 2724.pdf

Abstract: The influence of anions on the equilibrium and kinetic uptake of heavy metals from an aqueous solution by a novel nitrogen-type chelating adsorbent was evaluated. Equilibrium experiments revealed that stoichiometric amounts of metals and anions are adsorbed by the resin. Kinetic studies showed that during the initial stage of adsorption, the anions are adsorbed by the adsorbent prior to the metal ions. This occurred almost simultaneously with an increase in solution pH. At equilibrium, the pH returned towards its initial value. The concentration of anion also fluctuated during the entire equilibration process. Following these observations, mechanisms governing the role of anions on enhancing capacity and rate of metal uptake of this type of chelating adsorbent type were established. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Cellulose, Chelating Adsorbent, Heavy Metal, Anions, Removal

Othman, M.Z., Roddick, F.A. and Snow, R. (2001), Removal of dissolved organic compounds in fixed-bed columns: Evaluation of low-rank coal adsorbents. Water Research, 35 (12), 2943-2949.

Full Text: W\Wat Res35, 2943.pdf

Abstract: Characterisation of a range of Victorian low-rank coal (VLRC) based and commercial adsorbents under continuous flow conditions was conducted in down flow fixed-bed columns. The effect of bed depth, hydraulic loading and initial concentration of the adsorbate 4-nitrophenol (4-NP) was studied. Prediction of the performance of the columns using bed-depth/service time analysis showed good agreement with the experimental results. The VLRC-based activated carbons gave lower service times for removal of 4-NP compared with the coconut-based commercial activated carbon Picactif. However, they showed comparable efficiency in terms of bed volumes treated and carbon usage rate (CUR). The VLRC-activated power station char (APSC) showed the lowest CUR of 0.57 g/L in comparison with 0.62 and 3.61 g/L exhibited by the commercial carbons Picactif and Hydraffin, respectively. The power station char (PSC) and Auschar gave poor CUR of 11.23 and 75.36 g/L, respectively. Three adsorbents were evaluated for the removal of natural organic matter (NOM) from aqueous solution. The breakthrough behaviour indicated that the pore size distribution of the adsorbents is an important physical characteristic for the adsorption of the NOM. There was a non-adsorbable fraction of the NOM that was a function of the type of adsorbent. In the presence of NOM, Picactif gave longer service time for the removal of 4-NP compared with APSC, consistent with the trend obtained in the absence of NOM. However, lower breakthrough times (at 10% C₀) of 44 and 47% were obtained for APSC and Picactif, respectively. Further removal (35%) of 4-NP was achieved over extended operation of the beds, however more frequent backwashing was required as a result of the biological growth exhibited in the presence of NOM.

Keywords: Adsorption, Low-Rank Coal, Victorian Coal, NOM, DOC, 4-NP, fixed-bed Column

Chu, W. (2001), Dye removal from textile dye wastewater using recycled alum sludge. Water Research, 35 (13), 3147-3152.

Full Text: W\Wat Res35, 3147.pdf

Abstract: The removal of dyes from textile dying wastewater by recycled alum sludge (RAS) generated by the coagulation process itself was studied and optimized. One hydrophobic and one hydrophilic dye were used as probes to examine the performance of this process. It was found that RAS is a good way of removing hydrophobic dye in wastewater, while simultaneously reducing the fresh alum dosage, of which one third of the fresh alum can be saved. The back-diffusion of residued dye from the recycling sludge is detected but is easily controlled as long as a small amount of fresh alum is added to the system. The use of RAS is not recommended for the removal of hydrophilic dyes, since the high solubility characteristics of such dyes can cause deterioration in the water quality during recycling. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Alum, Dye, Hydrophilic, Hydrophobic, Recycle, Sludge, Water

Chen, B., Hui, C.W. and McKay, G. (2001), Film-pore diffusion modeling for the sorption of metal ions from aqueous effluents onto peat. Water Research, 35 (14), 3345-3356.

Full Text: W\Wat Res35, 3345.pdf

Abstract: The sorption of three metal ions, namely, copper, nickel and lead onto sphagnum peat moss has been studied using an agitated batch sorber system. The equilibrium isotherms were determined and kinetic runs were performed over a range of concentrations for each metal ion. A film-pore diffusion mass transfer model has been developed based on a single effective diffusion coefficient for each system. Error analysis of the experimental and theoretical data indicated relatively large errors at low initial metal ion concentrations. Therefore the model was modified to introduce a surface coverage concentration dependent effective diffusivity to account for a contribution from surface diffusion. (C) 2001 Elsevier Science Ltd. Alt rights reserved.

Keywords: Batch Adsorption, Modeling, Film-Pore Diffusion, Metal Ions, Peat, Shrinking-Core Model, Bovine Serum-Albumin, Surface-Diffusion, Activated Carbon, Mass-Transfer, Multicomponent Adsorption, Concentration-Dependence, Intraparticle Diffusion, Heterogeneous Surfaces, Exchange Kinetics

Meshko, V., Markovska, L., Mincheva, M. and Rodrigues, A.E. (2001), Adsorption of basic dyes on granular acivated carbon and natural zeolite. Water Research, 35 (14), 3357-3366.

Full Text: W\Wat Res35, 3357.pdf

Abstract: The adsorption of basic dyes from aqueous solution onto granular activated carbon and natural zeolite has been studied using an agitated batch adsorber. The influence of agitation, initial dye concentration and adsorbent mass has been studied. The parameters of Langmuir and Freundlich adsorption isotherms have been determined using the adsorption data. Homogeneous diffusion model (solid diffusion) combined with external mass transfer resistance is proposed for the kinetic investigation. The dependence of solid diffusion coefficient on initial concentration and mass adsorbent is represented by the simple empirical equations. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Basic Dye, Activated Carbon, Natural Zeolite, Homogeneous Diffusion Model, External Mass Transfer Resistance, Activated Carbon, Surface-Diffusion, Mass-Transfer, Liquid, Equilibrium, Adsorbents

Ćurković, L., Cerjan-Stefanović, Š. and Rastovèan-Mioè, A. (2001), Batch Pb²⁺ and Cu²⁺ removal by electric furnace slag. Water Research, 35 (14), 3436-3440.

Full Text: W\Wat Res35, 3436.pdf

Abstract: An evaluation of the application of electric furnace slag (EFS) as an adsorbent to remove Pb²⁺ and Cu²⁺ from industrial effluents is presented. The paper examines phase composition or EFS X-ray diffraction of powder. In the batch experiments, parameters studied include the effect of initial concentration of lead and copper ions, temperature, and contact time. Over the temperature range studied (293-313 K) the results of adsorption experiments could be Fitted by using both Langmuir and Freundlich models and thermodynamic values of DeltaG(0), DeltaH(0) and DeltaS(0) corresponding to each adsorption process were calculated. Satisfactory conformity between experimental data and the model-predicted values was expressed by the correlation coefficient (R²). Both Langmuir and Freundlich models described the Pb²⁺ and Cu²⁺ sorption processes adequately, with correlation coefficient (R²) values ranging from 0.9760 to 0.9994. Data from this study indicated the potential use of the tested electric furnace slag, a by-product from ‘Felis’ foundry in Sisak, Croatia, as Pb²⁺ and Cu²⁺ sorbents front the industrial effluents. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Lead, Copper, Heavy Metals, Electric Furnace Slag, Adsorption, Metal-Ion Exchange, Aqueous-Solution, Equilibrium Uptake, Sorption Dynamics, Column Operations, Activated Slag, Zeolites, Adsorption, Carbon

An, H.K., Park, B.Y. and Kim, D.S. (2001), Crab shell for the removal of heavy metals from aqueous solution. Water Research, 35 (15), 3551-3556.

Full Text: W\Wat Res35, 3551.pdf

Abstract: The ability of crab shell to remove heavy metals from aqueous solution was evaluated by comparing with that of several sorbents (cation exchange resin, zeolite, granular activated carbon, powdered activated carbon). All experiments were conducted using several heavy metal ion solutions (Pb, Cd, Cu, Cr). The orders of heavy metal removal capacity and initial heavy metal removal rate were found as crab shell>cation exchange resin>zeolite>powdered activated carbon greater than or equal to granular activated carbon. Therefore, crab shell is satisfactory as a good biosorbent for the heavy metal removal. The study indicates that the removal of these heavy metals is selective, with Pb and Cr being removed in preference to Cd and Cu. The sorption equilibrium of heavy metal ions on sorbents was modeled on the applications of Langmuir and Freundlich. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Biosorbents, Heavy Metal, Crab Shell, Cation Exchange Resin, Zeolite, Granular Activated Carbon, Powdered Activated Carbon, Rhizopus-arrhizus Biomass, Ions, Biosorbents, Biosorption

? Yu, J., Wang, X.W. and Yue, P.L. (2001), Optimal decolorization and kinetic modeling of synthetic dyes by Pseudomonas strains. Water Research, 35 (15), 3579-3586.

Full Text: 2001\Wat Res35, 3579.pdf

Abstract: Pseudomonas spp were isolated from an anaerobic-aerobic dyeing house wastewater treatment facility as the most active azo-dye degraders. Decolorization of azo dyes and non-azo dyes including anthraquinone, metal complex and indigo was compared with individual strains and a bacterial consortium consisting of the individual strain and municipal sludge (50:50 wt). The consortium showed a significant improvement on decolorization of two recalcitrant non-azo dyes, but little effect on the dyes that the individual strains could degrade to a great or moderate extent. Decolorization of Acid violet 7 (monoazo) by a Pseudomonas strain GM3 was studied in detail under various conditions. The optimum decolorization activity was observed in a narrow pH range (7-8), a narrow temperature range (35-40 degreesC), and at the presence of organic and ammonium nitrogen. Nitrate had a severe inhibitory effect on azo dye decolorization: 10 mg/L led to 50% drop in decolorization activity and 1000 mg/L to complete activity depression. A kinetic model is established giving the dependence of decolorization rate on cell mass concentration (first-order) and dye concentration (half order). The rate increased with temperature from 10 to 35 degreesC, which can be predicted by Arrhenius equation with the activation energy of 16.87 kcal/mol and the frequency factor of 1.49×1011 (mgL)(1/2)/g DCM min. (C)2001 Elsevier Science Ltd. All rights reserved.

Keywords: Activation, Activation Energy, Activity, Ammonium, Anaerobic Azo Reduction, Anaerobic-Aerobic Treatment, Azo Dye, Azo Dyes, Azo-Dye, Bacterial Consortium, Biodegradation, Biotreatment, Complex, Concentration, Decolorization, Degradation, Dependence, Depression, Drop, Dye, Dyeing, Dyes, Energy, First Order, Granular Sludge, Indigo, Inhibitory Effect, Kinetic, Kinetic Model, Kinetic Modeling, Mass Concentration, Metal, Model, Modeling, Municipal, Municipal Sludge, Nitrogen, Order, Organic, pH, Pseudomonas, Pseudomonas Decolorization Kinetics, Range, Simulated Textile Effluent, Sludge, Synthetic, Synthetic Dye Degradation, Synthetic Dyes, System, Temperature, Treatment, Waste-Water, Wastewater, Wastewater Treatment

Costley, S.C. and Wallis, F.M. (2001), Bioremediation of heavy metals in a synthetic wastewater using a rotating biological contactor. Water Research, 35 (15), 3715-3723.

Full Text: W\Wat Res35, 3715.pdf

Abstract: Immobilised microorganisms provide a potential system for the treatment of metal-contaminated waters. This study investigates the efficiency of a rotating biological contactor (RBC) in the treatment of waters contaminated with cadmium, copper and zinc in multiple sorption–desorption cycles. Each sorption cycle extended over a period of 12 weeks at an HRT of 24h to determine the efficiency of the system over a protracted period of time. The removal pattern observed in the initial cycle, namely Cu>>Zn>Cd, was repeated in both subsequent cycles. After completion of each cycle metals were successfully desorbed by means of an acid wash. The sorption ability of the biofilm was not adversely affected by the desorption process as evidenced by the similar metal removal rates obtained in each of the three sorption cycles. These results suggest that RBCs can be used successfully in the treatment of high-strength metal-contaminated wastewaters. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Rotating Biological Contactor, Biofilms, Heavy Metals, Sorption, Desorption, Cadmium, Copper, Zinc

Al-Degs, Y., Khraisheh, M.A.M. and Tutunji, M.F. (2001), Sorption of lead ions on diatomite and manganese oxides modified diatomite. Water Research, 35 (15), 3724-3728.

Full Text: W\Wat Res35, 3724.pdf

Abstract: Naturally occurring diatomaceous earth (diatomite) has been tested as a potential sorbent for Pb(II) ions. The intrinsic exchange properties were further improved by modification with manganese oxides. Modified adsorbent (referred to as Mn-diatomite) showed a higher tendency for adsorbing lead ions from solution at pH 4. The high performance exhibited by Mn-diatomite was attributed to increased surface area and higher negative surface charge after modification. Scanning electron microscope pictures revealed a birnessite structure of manganese oxides, which was featured by a plate-like-crystal structure. Diatomite filtration quality was improved after modification by manganese oxides. Good filtration qualities combined with high exchange capacity emphasised the potential use of Mn-diatomite in filtration systems. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Diatomaceous Earth (Diatomite), Manganese Oxides, Adsorption and Filtration

Ahsan, S., Kaneco, S., Ohta, K., Mizuno, T. and Kani, K. (2001), Use of some natural and waste materials for waste water treatment. Water Research, 35 (15), 3738-3742.

Full Text: W\Wat Res35, 3738.pdf

Abstract: A fundamental study was conducted to assess removal and filtration capacity of waste and natural indigenous materials as treatment mediums e.g., shell, limestone, waste paper mixed with refuse concrete, refuse cement, also processed nitrolite, charcoal-bio and charcoal. Under room temperature condition removal of phosphoric, nitric a-nd ammonium-ions, filtration of suspended substance (SS) together with removal of COD in waste water was investigated. Influence of particle size effect for all treatment mediums except for waste paper was pursued. Significant improvement of waste water quality with respect to SS, phosphoric ions and decrease in COD is possible by treating with these filtration mediums. With specific reference to some treatment mediums NO₃-N and NH₄-N showed reasonable improvement in quality, although generally removal effect was not very significant. Efficacy of treatment was dependent on the particle size of treatment mediums in general, however, nitrolite for NH₄-N, charcoal-A for SS and COD, refuse cement mixed with waste paper for PO₄ ion removal showed insignificant variability on the particle size effect. Results of this fundamental study demonstrate effectiveness and feasibility for applied application of these proposed waste and naturally available treatment ingredients at lower cost. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Waste Treatment, Removal, Filtration, Indigenous Materials, Removal

Li, Z.H. and Bowman, R.S. (2001), Retention of inorganic oxyanions by organo-kaolinite. Water Research, 35 (16), 3771-3776.

Full Text: W\Wat Res35, 3771.pdf

Abstract: A natural kaolinite (KGa-1b) was treated with the surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) to a level twice that of the cation exchange capacity (CEC). Sorption of nitrate. arsenate, and chromate by the resultant organo-kaolinite was then quantified. Sorption of each oxyanion was well-described by the Langmuir isotherm. Sorption of nitrate was the greatest. with a Langmuir sorption maximum of 24 mmol/kg, although chromate showed the highest sorption affinity of 20 L/kg. Sorption of nitrate. arsenate, and chromate on organo-kaolinite was at least two orders of magnitude greater than their sorption on unmodified kaolinite. Desorption of the bromide counterion indicated that each of the oxyanions was retained by ion exchange on an HDTMA bilayer formed on the organokaolinite. Chromate sorption on the organo-kaolinite was unaffected by solution pH in the range 5-9, but decreased at pH 11 due to competition of OH- for anion exchange sites. Similarly, chromate exchange by organo-kaolinite was reduced in the presence of high background levels of chloride. Chromate was effectively retained when flowing through a packed bed of organo-kaotinite: after an input of more than 40 pore volumes. the effluent concentration of chromate was less than 10% of the input concentration. and 90% of the original HDTMA remained on the organo-kaolinite. The results demonstrate that properly prepared organoclays can remove oxyanions, as well as nonpolar organics, from contaminated waters. (C) 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Hdtma, Surfactant, Organoclay, Sorption, Anion Exchange, Surfactant-Modified Zeolite, Cationic Surfactant, Natural Clinoptilolite, Sorption, Chromate, Clay, Contaminants, Hexadecyltrimethylammonium, Adsorption, Stability

Ko, D.C.K., Porter, J.F. and McKay, G. (2001), Film-pore diffusion model for the fixed-bed sorption of copper and cadmium ions onto bone char. Water Research,