Personal Research Database

Full Text: W\Wat Sci Tec47, 189.pdf

Abstract: Four naturally derived chitinous materials, commercial cryogenically milled carapace (CCMC), mechanically milled carapace (MMC), chitin and chitosan, were assessed for their ability to remove a range of alkali, alkaline earth, transition and heavy metals from aqueous media in flow-through column trials. The materials showed a poor affinity for the alkali metals and alkaline earth metals but significantly greater affinity for transition and heavy metals: an: general, chitin was the least efficient material for removal of transition and heavy metals (similar to35%) while chitosan was most effective (>99%). CCMC and MMC; both removed >90% of transition and heavy metals tested from solution. Batch studies conducted using copper as a reference metal demonstrated that removal was dependent on a number of variables including pH, contact time, particle size, metal concentration, metal type and the physic-chemical characteristics of the materials. Detailed analysis of the results from these studies indicate that removal is a complex process and that metals can be sequestered from solution by a number-of mechanisms including adsorption, absorption and precipitaion.

Keywords: Biosorbents, Chitin, Chitosan, Crabshell, Heavy Metals Transition Metals, Cancer-Pagurus L, Heavy-Metals, Waste-Water, Crab Shell, Lead, Precipitation, Biosorption, Adsorption, Copper, Mineralization

Bianchi, A., Papini, M.P., Corsi, A., Behra, P. and Beccari, M. (2003), Competitive transport of cadmium and lead through a natural porous medium: Influence of the solid/liquid interface processes. Water Science and Technology, 48 (3), 9-16.

Full Text: W\Wat Sci Tec48, 9.pdf

Abstract: Contaminated groundwater typically contains different metal contaminants which may compete with each other for the same adsorption sites. Understanding the fate of these micro-pollutants is of primary importance for the assessment of the risk associated with their dispersion in the environment and for the evaluation of the most appropriate remediation technology. In this regard, column techniques can be considered as useful tools both to perform transport experiments and to obtain equilibrium adsorption data without any perturbation of the actual solid/liquid interface. Cd and Pb monocomponent step column experiments were used to obtain adsorption isotherms on a natural aquifer material. A General Composite approach was used to define the equilibrium adsorption model characterized by two types of sites (ion-exchange and surface complexation sites). Coupling the adsorption model with the Advection-Dispersion equation (by IMPACT code) allowed us to well represent the monocomponent step experiments. The model was successfully used to predict the competitive Cd and Pb transport behaviour. Cd peaks of concentration due to Pb competition were experimentally observed and simulated by the model. This behaviour can be described only by an accurate modelling of the interaction and cannot be predicted by simple isotherms (such as Langmuir or Freundlich type).

Keywords: Adsorption, Competition, Heavy Metals, Modelling, Transport, Adsorption, Soil

Braskerud, B.C. and Haarstad, K. (2003), Screening the retention of thirteen pesticides in a small constructed wetland. Water Science and Technology, 48 (5), 267-274.

Full Text: W\Wat Sci Tec48, 267.pdf

Abstract: When pesticides are used in arable watersheds, residues are usually found in the recipients. However, small constructed wetlands (CWs) in first and second order streams can reduce the loss of pesticides, since water purification processes are stimulated. This paper presents the results of adding 13 pesticides to a CW in Norway. The relative retention increased between 0 and 67% for the, pesticides fluroxypyr, bentazone, dicamba, mecoprop, propiconazole, MCPA, dichlorprop, linuron, fenpropimorph, metalaxyl, metribuzin, metamitron and propachlor. In many cases, the CW reduced the peak concentrations to values regarded as non-toxic for aquatic life, even though the wetland covered less than 0.4% of the watershed surface area, and the average hydraulic load often was above 0.8 m d^-1. Possible retention factors were adsorption to soil particles and organic matter, sedimentation of particles, low or high redox-potential, and biodegradation of nitrogen-rich pesticides. However, the retention processes are complex, and are not fully understood.

Keywords: Constructed Wetland, Diffuse Pollution, Fungicide, Herbicide, Nonpoint-Source Pollution, Atrazine, Removal, Water

Reddad, Z., Gerente, C., Andres, Y. and Le Cloirec, P. (2004), Lead removal by a natural polysaccharide in membrane reactors. Water Science and Technology, 49 (1), 163-170.

Full Text: W\Wat Sci Tec49, 163.pdf

Abstract: Industrial wastewaters often contain heavy metal ions that are toxic to many living species. Therefore, economic treatment methods are investigated, involving the sorption of metal ions onto wastes or natural materials. In the present work, the ability of sugar beet pulp, a common waste of the sugar industry, to remove Pb²⁺ polluted waters is investigated. The kinetic and equilibrium experiments were performed in batch reactor in order to determine the Pb²⁺ adsorption mechanisms onto the polysaccharide. The dynamic studies of Pb²⁺ fixation onto the natural polysaccharide involve an adsorption reactor coupled with microfiltration membrane in order to confine the adsorbent particles. A mass balance model based on the Langmuir equilibrium isotherm was used to describe the Pb²⁺ breakthrough curves. This model successfully simulated the entire breakthrough curves whatever the operating conditions used. It provides a useful tool for process simulation and optimisation.

Keywords: Adsorption, Metal Ions, Microfiltration, Modelling, Polysaccharides, Sugar-Beet Pulp, Metal-Ions, Aqueous-Solution, Sorption, Binding, Cations

? Bathe, S., Mohan, T.V.K., Wuertz, S. and Hausner, M. (2004), Bioaugmentation of a sequencing batch biofilm reactor by horizontal gene transfer. Water Science and Technology, 49 (11-12), 337-344.

Full Text: 2004\Wat Sci Tec49, 337.pdf

Abstract: Bioaugmentation by introduction of catabolic genes residing on mobile genetic elements into the microbial community of a soil or wastewater environment might be an alternative to bioaugmentation by addition of bacterial cells with chromosomally encoded catabolic genes. This study investigates the possibility to enhance degradation of the xenobiotic model compound 2,4-dichlorophenoxyacetic acid in a sequencing batch biofilm reactor (SBBR) by using the conjugative plasmid pJP4 carrying genes for 2,4-D degradation. After introduction of a plasmid donor strain to a lab-scale SBBR operated without 2,4-D, the number of plasmid-carrying cells first dropped, and then increased after switching to 2,4-D as the sole carbon source. The donor cells were unable to grow in the applied synthetic wastewater with 2,4-D as the sole carbon source. Transconjugants could be detected both by culture-dependent and culture-independent methods in the 2,4-D degrading biofilm. In contrast to 90% 2,4-D degradation in the bioaugmented reactor within 40 h, a control reactor which had not received the plasmid still contained 60% of the initial 2,4-D concentration after 90 h. This experiment clearly demonstrates the introduction of 2,4-D degradative genes into a microbial biofilm and indicates that horizontal gene transfer is a promising tool for bioaugmentation of reactors treating wastewater.

Keywords: Bioaugmentation, Catabolic Plasmid PJP4, Conjugation, 2,4-Dichlorophenoxyacetic Acid (2,4-D), PCR-DGGE, Sequencing Batch Biofilm Reactor (SBBR), 2,4-Dichlorophenoxyacetic Acid Degradation, Comamonadaceae, Plasmids, Sludge, PJP4

? Acuna-Askar, K., Villarreal-Chiu, J.F., Gracia-Lozano, M.V., Garza-Gonzalez, M.T., Chavez-Gomez, B., Rodiguez-Sanchez, I.P. and Barrera-Saidana, H.A. (2004), BTE-OX biodegradation kinetics with MTBE through bioaugmentation. Water Science and Technology, 50 (5), 85-92.

Full Text: 2004\Wat Sci Tec50, 85.pdf

Abstract: The biodegradation kinetics of BTE-oX and MTBE, mixed all together, in the presence of bioaugmented bacterial populations as high as 880 mg/L VSS was evaluated. The effect of soil in aqueous samples and the effect of Tergitol NP-10 on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 36 hours, every 6 hours. Benzene and o-xylene biodegradation followed a first-order one-phase kinetic model, whereas toluene and ethylbenzene biodegradation was well described by a first-order two-phase kinetic model in all samples. MTBE followed a zero-order removal kinetic model in all samples. The presence of soil in aqueous samples retarded BTE-oX removal rates, with the highest negative effect on o-xylene. The presence of soil enhanced MTBE removal rate. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged from 95.4-99.7% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged from 55.9-90.1% and 15.6-30.1%, respectively.

Keywords: Eioaugmentation, Biodegradation, Bioremediation, BTEX, MTBE, Tergitol NP-10, Utyl Ether MTBE, Groundwater, Reactors, Isomers, Xylene, Batch

? Xu, H., Tay, J.H., Foo, S.K., Yang, S.F. and Liu, Y. (2004), Removal of dissolved copper(II) and zinc(II) by aerobic granular sludge. Water Science and Technology, 50 (9), 155-160.

Full Text: 2004\Wat Sci Tec50, 155.pdf

Abstract: This study investigated the adsorption kinetics of dissolved copper(II) and zinc(II) by aerobic granular sludge. Two series of batch experiments were conducted at different initial copper(II), zinc(II) concentrations (C-o) and initial granule concentrations (X-o). Results showed that the biosorption kinetics of individual copper(II) and zinc(II) by aerobic granules were closely related to C-o and X-o. The maximum biosorption capacity of individual copper(II) and zinc(II) by aerobic granules was 246.1 mg g^-1 and 180 mg g^-1 respectively. In order to theoretically interpret the results obtained, two kinetic models previously developed for biosorption were employed and compared in this study. It was found that the model proposed by Liu et al. (2003) could fit the experimental data very well, but the second-order model failed to fit the data in some cases. It appears that aerobic granules would be potential biosorbent with high efficiency for the removal of dissolved copper(II) and zinc(II) from wastewater.

Keywords: Aerobic Granules, Biosorption Kinetics, Copper(II), Initial Conditions, Zinc(II), Aqueous-Solutions, Biosorption, Biomass, Cadmium

? Acuna-Askar, K., Gracia-Lozano, M.V., Villarreal-Chiu, J.F., Marmolejo, J.G., Garza-Gonzalez, M.T. and Chavez-Gomez, B. (2005), Effect of soil and a nonionic surfactant on BTE-oX and MTBE biodegradation kinetics. Water Science and Technology, 52 (8), 107-115.

Full Text: 2005\Wat Sci Tec52, 107.pdf

Abstract: The biodegradation kinetics of BTE-oX and MTBE, mixed all together, in the presence of 905 mg/L VSS of BTEX-acclimated biomass was evaluated. Effects of soil and Tergitol NP-10 in aqueous samples on substrate biodegradation rates were also evaluated. Biodegradation kinetics was evaluated for 36 hours, every 6 hours. MTBE biodegradation followed a first-order one-phase kinetic model in all samples, whereas benzene, toluene and ethylbenzene biodegradation followed a first-order two-phase kinetic model in all samples. O-xylene biodegradation followed a first-order two-phase kinetic model in the presence of biomass only. Interestingly, o-xylene biodegradation was able to switch to a first-order one-phase kinetic model when either soil or soil and Tergitol NP-10 were added. The presence of soil in aqueous samples retarded benzene, toluene and ethylbenzene removal rates. O-xylene and MTBE removal rates were enhanced by soil. The addition of Tergitol NP-10 to aqueous samples containing soil had a positive effect on substrate removal rate in all samples. Substrate percent removals ranged 77-99.8% for benzene, toluene and ethylbenzene. O-xylene and MTBE percent removals ranged 50.1-65.3% and 9.9-43.0%, respectively.

Keywords: Biodegradation, BTEX, MTBE, Butyl Ether MTBE, Substrate Interactions, Mixtures, Reactors, Isomers, Toluene, Xylene, Batch

? Den, W. and Huang, C. (2006), Parameter optimization and design aspect for electrocoagulation of silica nano-particles in wafer polishing wastewater. Water Science and Technology, 53 (6), 187-194.

Full Text: 2006\Wat Sci Tec53, 187.pdf

Abstract: A systematic procedure has been proposed for the design of a multi-channel, continuous-flow electrocoagulation reactor of mono-polar configuration for the removal of sub-micron particles from wastewater. Using the chemical-mechanical-planarization (CMP) process as the target source of wastewater, a series of laboratory-scale studies were conducted to determine the required operating conditions for the efficient removal of the ultrafine particles. These operating criteria included charge loading (> = 8 F m^-3), current density (> = 5.7 A m^-2), hydraulic retention time (> = 60 min), as well as the initially operational pH (7 similar to 10). Furthermore, a steady-state transport equation with second-order reaction kinetics was employed to describe the rate of coagulation as the rate-limiting factor, The actual kinetic constant determined from the laboratory-scale experiments was approximately 1.2×10^-21 m³ s^-1, which was three orders of magnitude smaller than that calculated based on Brownian diffusion during the coagulation. The model was subsequently validated with a series of experiments using a pilot-scale electro-coagulation reactor geometrically similar to the laboratory-scale reactor with nearly twenty times volumetric scale-up.

Keywords: CMP, Electrocoagulation, Nano-Particle, Silica Colloids, Slurry, Wafer Polishing, Electroflotation

? Jiang, J.Q., Xu, Y., Simon, J., Quill, K. and Shettle, K. (2006), Removal of boron (B) from waste liquors. Water Science and Technology, 53 (11), 73-79.

Full Text: 2007\Wat Sci Tec53, 73.pdf

Abstract This paper explores the use of electrocoagulation to remove boron from waste effluent in comparison with alum coagulation. In treating model test wastes, greater boron removals were achieved with electrocoagulation at low doses than conventional alum coagulation when reaction was undertaken for the same conditions (pH 8.5, and initial boron concentration was 500 mg/L). Al electrocoagulation can achieve good boron removal performance (68.3%) at a dose of 2.1 (as molar ratio of Al:B, and for current density of 62.1 A/m2), while alum coagulation can only achieve the maximum boron removal of 56% at a dose of 2.4. Also, Al electrocoagulation can remove 15–20% more boron than alum coagulation for the same dose compared in the treatment of both model test wastes and industry effluent. The estimation of running costs shows that to achieve 75% boron removal from industry waste effluent, i.e. removing 150 g of boron from 1 m3 of effluent, electrocoagulation was 6.2 times cheaper than alum coagulation. The economic advantage of electrocoagulation in the treatment of boron-containing waste effluent is thus significant.

Keywords: Boron, Electrocoagulation, Waste Treatment

? Yang, Y., Tomlinson, D., Kennedy, S. and Zhao, Y.Q. (2006), Dewatered alum sludge: A potential adsorbent for phosphorus removal. Water Science and Technology, 54 (5), 207-213.

Full Text: 2006\Wat Sci Tec54, 207.pdf

Abstract: Alum sludge refers to the by-product from the processing of drinking water in water treatment works. In this study, groups of batch experiments were designed to identify the characteristics of dewatered alum sludge for phosphorus adsorption. Air-dried alum sludge (moisture content 10.2%), which was collected from a water treatment works in Dublin, was subjected to artificial P-rich wastewater adsorption tests using KH₂PO₄ as a model P source. Adsorption behaviours were investigated as a function of amount and particle size of alum sludge, pH of solution and adsorption time. The results have shown that pH plays a major role not only in the adsorption process but also in the adsorption capacity. With regard to adsorption capacity, this study reveals the Langmuir adsorption isotherm being the best fit with experimental data (R-2 = 0.98-0.99). The maximum adsorption capacities range from 0.7 to 3.5 mg-P/g when the pH of the synthetic P solution was varied from 9.0 to 4.3, accordingly. The outcome of this study indicated that alum sludge is suitable for use as an adsorbent for removal of phosphate from wastewater.

Keywords: Adsorption, Alum Sludge, Phosphorus, Reuse, Wastewater Treatment, Waste-Water, Aqueous-Solution, Adsorption, Phosphate, Oxide, Media

? Deng, S., Ting, Y.P. and Yu, G. (2006), Chromate sorption and reduction kinetics onto an aminated biosorbent. Water Science and Technology, 54 (10), 1-8.

Full Text: 2006\Wat Sci Tec54, 1.pdf

Abstract: A novel biosorbent, was prepared by chemically grafting of polyethylenimine (PEI) onto the fungal biomass of Penicillium chrysogenum through a two-step reaction. The modified biosorbent is favorable for the removal of anionic Cr(VI) species from aqueous solution due to the protonation of amine groups on the biomass surface. The sorption capacity for Cr(VI) increased by 7.2-fold after surface modification. Sorption kinetics results show that the pseudo-second-order kinetic model described the experimental data well. During the sorption process, X-ray photoelectron spectroscopy (XPS) was used to analyze the chromium species on the biosorbent surface and the results indicate that part of the Cr(VI) ions were reduced to Cr(III) ions which can be chelated with the amine groups on the biomass surface. The reduced Cr(III) ions formed some aggregates on the surface at higher solution pHs.

Keywords: Aminated Biosorbent, Cr(VI) Removal, Sorption Kinetics, XPS Spectra, Hexavalent Chromium, Modified Biomass, Biosorption, Removal, Enhancement, Cu(II), Cr(VI), Ions, Lead

? Vinitnantharat, S. Rattanasirisophon, W. and Ishibashi, Y. (2007), Modification of granular activated carbon surfaceby chitosan coating for geosmin removal: Sorption performances. Water Science and Technology, 55 (5), 145-152.

Full Text: 2007\Wat Sci Tec55, 145.pdf

Abstract: This study presents the results of the sorption performances for geosmin removal by sorption onto granular activated carbons (GAC) manufactured from different raw materials of coconut shell and bituminous coal. The surface of GAC was modified by chitosan coating. The 90% deacetylated chitosan flakes were used for coating on GAC with the GAC: chitosan ratio of 5:1. The surface of GAC was characterised by scanning electron microscope (SEM) analysis, Fourier transform infrared spectroscopy and measurement of the pH solution of GAC samples. The sorption of geosmin onto the chitosan for both uncoated and coated GACs could be described by the Freundlich adsorption model. Data revealed that the sequence of Freundlich constant (K_F) was chitosan coated bitominous coal (CB) > uncoated bituminous coal (UB) > chitosan coated coconut shell (CC)  uncoated coconut shell (UC). The bituminous coal based GAC with chitosan coating had a maximum capacity of 23.57 mg/g which was approximately two-fold of uncoated bituminous coal based GAC. Two simplified kinetic models, pseudo-first order and pseudo-second order, were tested to investigate the sorption mechanisms. It was found that the intraparticle diffusion was a rate controlling step for the sorption and followed the pseudo-second order equation.

Keywords: Adsorption, Chitosan, GAC, Geosmin, Odour Removal

? Wong, K.S., Wong, K.H., Ng, S., Chung, W.K. and Wong, P.K. (2007), Adsorption of copper ion on magnetite-immobilised chitin. Water Science and Technology, 56 (7), 135-143.

Full Text: 2007\Wat Sci Tec56, 135.pdf

Abstract: The adsorption of Cu²⁺ from aqueous solution by magnetite-immobilised chitin (MC) was studied in batch mode. Two conventional adsorbents, cation exchange resin (CER) and activated carbon (AC) were used for the comparison. The physicochemical parameters including pH, concentration of adsorbent, temperature and initial Cu²⁺ concentration were optimised. Under the optimised conditions, the removal efficiencies of Cu²⁺ for MC, CER and AC were 91.67, 93.36 and 89.16%, respectively. In addition, the removal capacities of Cu²⁺ for MC, CER and AC were 56.71, 74.84 and 6.55 mg/g, respectively. The adsorption isotherm studies indicated that the adsorptive behaviour of Cu²⁺ on three adsorbents could be well described by the Langmuir model. The maximum adsorption capacities (q(max)) for MC, CER and AC were 53.19, 89.29 and 5.82 mg/g, respectively. The applicability of the kinetic model has been investigated for MC. Experimental results indicated that a pseudo-second-order reaction model provided the best description of the data with a correlation coefficient 0.999 for different initial Cu²⁺ concentrations. The rate constants were also determined. Various thermodynamic parameters such as standard free energy (Delta G(0)), enthalpy (Delta H-0) and entropy (Delta S-0) were calculated for predicting the adsorption nature of MC. The results indicated that this system was a spontaneous and endothermic process.

Keywords: Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption Isotherm, Aqueous Solution, Aqueous-Solutions, Carbon, Cation, Cation Exchange, Cells, Chitin, Comparison, Copper, Cu²⁺, Equilibrium, Isotherm, Kinetic, Kinetics, Kinetics, Langmuir, Magnetite-Immobilised Chitin, pH, Recovery, Removal, Shell, Solution, Temperature, Thermodynamic Parameters, Thermodynamics, Waste, Zinc Biosorption

? Yin, C.Y., Aroua, M.K. and Daud, W.M.A.W. (2007), Modification of granular activated carbon using low molecular weight polymer for enhanced removal of Cu²⁺ from aqueous solution. Water Science and Technology, 56 (9), 95-101.

Full Text: 2007\Wat Sci Tec56, 95.pdf

Abstract: Palm shell activated carbon was modified via surface impregnation with polyethyleneimine (PEI) to enhance removal of Cu²⁺ from aqueous solution in this study. The effect of PEI modification on batch adsorption of Cu²⁺ as well as the equilibrium behavior of adsorption of metal ions on activated carbon were investigated. PEI modification clearly increased the Cu²⁺ adsorption capacities by 68% and 75.86% for initial solution pH of 3 and 5 respectively. The adsorption data of Cu²⁺ on both virgin and PEI-modified AC for both initial solution pH of 3 and 5 fitted the Langmuir and Redlich-Peterson isotherms considerably better than the Freundlich isotherm.

Keywords: Activated Carbon, Adsorption, Adsorption, Batch, Carbon, Chelating Polymer, Copper, Copper(II), Cu²⁺, Cu²⁺ Adsorption, Equilibrium, Freundlich, Freundlich Isotherm, Granular Activated Carbon, Impregnation, Ions, Isotherm, Isotherms, Langmuir, Membranes, Metal Ions, Models, Modification, Nickel(II), Palm Shell, Palm Shell Activated Carbon, Ph, Polyethyleneimine, Polymer, Removal, Sorption, Surface Sites, Water, Weight

? Paradelo, R., Moldes, A.B. and Barral, M.T. (2009), Treatment of red wine vinasses with non-conventional substrates for removing coloured compounds. Water Science and Technology, 59 (8), 1585-1592.

Full Text: 2009\Wat Sci Tec59, 1585.pdf

Abstract: Vinasses from the wine industry were treated with different materials to remove colour as a first step for treatment. Peat, several composts and red mud from bauxite refining were evaluated as adsorbents for coloured compounds, and their performances compared to that of activated charcoal. Among the materials assayed, grape marc vermicompost gave the best results, followed by peat. A sharp decrease of absorbance between 400-800 nm took place in vinasses after the treatments with these two materials, whereas the other substrates did not reduce the colour of the vinasses as did activate charcoal, grape marc vermicompost and peat. Moreover, grape marc vermicompost and peat were activated on high temperatures or grinding, producing better results in colour removal, although with negative effects on the electrical conductivity and nutrient concentration in the wastewater. The results of the treatment of vinasses with activated charcoal were reproduced and even overcame, in the case of the reduction of the optical density of vinasses at 665 nm, using grape marc vermicompost.

Keywords: Adsorption, Coloured Compounds, Degradation, Dye, Dye Removal, Grape Marc, Sorption, Vermicompost, Vinasses, Waste-Water

? Aksakal, Ö., Ucun, H. and Kaya, Y. (2009), Application of Eriobotrya japonica (Thunb.) Lindley (Loquat) seed biomass as a new biosorbent for the removal of malachite green from aqueous solution. Water Science and Technology,