Personal Research Database

Full Text: W\Wat Res38, 693.pdf

Abstract: The biosorption of cadmium(II) and zinc(II) ions onto dried Fontinalis antipyretica, a widely spread aquatic moss, was studied under different values of temperature, initial pH and water hardness. The equilibrium was well described by Langmuir adsorption isotherms. Maximum biosorption capacity of cadmium was independent on temperature and averaged 28.0 mg g^-1 moss, whereas for zinc, capacity increased with temperature, from 11.5 mg g^-1 moss at 5°C to 14.7 mg g^-1 moss at 30°C. Optimum adsorption pH value was determined as 5.0 for both metal ions. Cadmium uptake was unaffected by the presence of calcium ions, but zinc sorption was improved when water hardness increased from 101.1 to 116.3 mg CaCO₃ l^-1. Inversely, as hardness increases, the competition with calcium ions strongly reduces the affinity of the biosorbent for zinc.

Keywords: Aquatic Moss, Zinc, Cadmium, Sorption, Heavy Metals, Fontinalis Antipyretica

? Temmink, H. and Klapwijk, B. (2004), Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants. Water Research, 38 (4), 903-912.

Full Text: 2004\Wat Res38, 903.pdf

Abstract: Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C-12-homologue of linear alkyl benzene sulfonate (LAS-C-12). The pilot-plant was operated at influent LAS-C-12 concentrations between 2 and 12 mg l(-1) and at sludge retention times of 10 and 27 days. Effluent and waste sludge concentrations varied between 5 and 10 mug l(-1) and between 37 and 69 mug g(-1) VSS, respectively. In the sludge samples only 2-8% was present as dissolved LAS-C-12, whereas the remaining 92-98% was found to be adsorbed to the sludge. In spite of this high degree of sorption, more than 99% of the LAS-C-12 load was removed by biodegradation, showing that not only the soluble fraction but also the adsorbed fraction of LAS-C-12 is readily available for biodegradation. Sorption and biodegradation of LAS-C-12 were also investigated separately. Sorption was an extremely fast and reversible process and could be described by a linear isotherm with a partition coefficient of 3.21 g(-1) volatile suspended solids. From the results of biodegradation kinetic tests it was concluded that primary biodegradation of LAS-C-12 cannot be described by a (growth) Monod model, but a secondary utilisation model should be used instead. The apparent affinity of the sludge to biodegrade LAS-C-12 increased when the sludge was loaded with higher influent concentrations of LAS-C-12. (C) 2003 Elsevier Ltd. All rights reserved.

Keywords: Activated Sludge, Behavior, Biodegradation, Biodegradation Kinetics, Chemicals, Culture, Environment, Isotherm, Linear Alkylbenzene Sulfonate (LAS), Model, Monitoring, Organic Trace Compounds, Plant, Plants, Primary, Removal, Retention, Sewage, Sorption, Surfactant Monitoring Program, Utilisation, Waste-Water Treatment

? Doll, T.E. and Frimmel, F.H. (2004), Kinetic study of photocatalytic degradation of carbamazepine, clofibric acid, iomeprol and iopromide assisted by different TiO₂ materials: Determination of intermediates and reaction pathways. Water Research, 38 (4), 955-964.

Full Text: 2004\Wat Res38, 955.pdf

Abstract: The light-induced degradation of clofibric acid, carbamazepine, iomeprol and iopromide under simulated solar irradiation has been investigated in aqueous solutions suspended with different TiO₂ materials (P25 and Hombikat UV100). Kinetic studies showed that P25 had a better photocatalytic activity for clofibric acid and carbamazepine than Hombikat UV100. For photocatalytic degradation of iomeprol Hombikat UV100 was more suitable than P25. The results can be explained by the higher adsorption capacity of Hombikat UV100 for iomeprol.

The study also focuses on the identification and quantification of possible degradation products. The degradation process was monitored by determination of sum parameters and inorganic ions. In case of clofibric acid various aromatic and aliphatic degradation products have been identified and quantified. A possible multi-step degradation scheme for clofibric acid is proposed. This study proves the high potential of the photocatalytic oxidation process to transform and mineralize environmentally relevant pharmaceuticals and contrast media in water. (C) 2003 Elsevier Ltd. All rights reserved.

Keywords: Anatase/Rutile (P25), Anatase (Hombikat UV100), Degradation Products, Aqueous Suspensions, Pharmaceuticals, Contrast Media, Drinking-Water Treatment, Ray Contrast-Media, Aquatic Environment, Pharmaceuticals, Drugs, Ozonation, Oxidation, Removal, Samples, Agents

Villaescusa, I., Fiol, N., Martínez, M., Miralles, N., Poch, J. and Serarols, J. (2004), Removal of copper and nickel ions from aqueous solutions by grape stalks wastes. Water Research, 38 (4), 992-1002.

Full Text: W\Wat Res38, 992.pdf

Abstract: In the present work, the usefulness of grape stalks wastes generated in the wine production process has been investigated for the removal of copper and nickel ions from aqueous solutions. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact. The influence of pH, sodium chloride and metal concentration on metal removal has been studied. Uptake showed a pH-dependent profile. Maximum sorption for both metals was found to occur at around pH 5.5–6.0. An increase of sodium chloride concentration caused a decrease in metal removal. Langmuir isotherms, at pH 6.0, for each metal were used to describe sorption equilibrium data. Maximum uptake obtained was 1.59×10^-4 mol of copper and 1.81×10^-4 mol of nickel per gram of dry sorbent.

Sorption of copper and nickel on grape stalks released an equivalent amount of alkaline and alkaline earth metals (K⁺, Mg²⁺, Ca²⁺) and protons, indicating that ionic exchange is predominantly responsible for metal ion uptake. Fourier transform infrared (FTIR) spectrometry analysis indicated that lignin C–O bond might be involved in metal uptake.

Equilibrium batch sorption studies were also performed using a two metal system containing (Cu(II)+Ni(II)). In the evaluation of the two metal sorption system performance, single isotherm curves had to be replaced by three-dimensional sorption isotherm surface. In order to describe the isotherm surface mathematically, the extended-Langmuir model was used. Nickel was found to be much more sensitive to the presence of copper than copper is to the presence of nickel.

Keywords: Grape Stalks Wastes, Copper, Nickel, Metal Removal, Sorption Isotherms

Pagnanelli, F., Beolchini, F., Di Biase, A. and Vegliò, F. (2004), Biosorption of binary heavy metal systems onto Sphaerotilus natans cells confined in an UF/MF membrane reactor: Dynamic simulations by different Langmuir-type competitive models. Water Research, 38 (4), 1055-1061.

Full Text: W\Wat Res38, 1055.pdf

Abstract: Continuous heavy metal biosorption in membrane reactor apparatus using binary metal solutions was here considered. A dynamic model was developed to simulate biosorption performances on the base of metal mass balances in the system considering biosorption as an equilibrium process. The effect of three Langmuir-type competitive models on dynamic simulations of biosorption was then studied by using predictive equilibrium models (whose adjustable parameters were determined only by single metal system biosorption data) and not predictive equilibrium models (adjustable parameters directly by binary biosorption data). Predictive competitive models can give simulation profiles that are different from those obtained using non-predictive models. This detachment is due to the non-ideal competition among metals in solution which cannot be predicted only on the base of biosorption data in single metal systems. The dynamic model for multi-component biosorption here proposed was compared with experimental results reported in the literature and obtained using a biomass in a similar membrane reactor apparatus with ternary metal systems. The simulated profiles (obtained by using predictive equilibrium models) can reproduce qualitatively the specific adsorbent selectivity and the overshoot regions in the permeate concentrations of the metals with the minor affinity.

Keywords: Heavy Metals, Biosorption, Membrane Reactor, Langmuir-Type Models, Dynamic Modelling

Ahmedna, M., Marshall, W.E., Husseiny, A.A., Rao, R.M. and Goktepe, I. (2004), The use of nutshell carbons in drinking water filters for removal of trace metals. Water Research, 38 (4), 1062-1068.

Full Text: W\Wat Res38, 1062.pdf

Abstract: Filtration of drinking water by point-of-use (POU) or point-of-entry (POE) systems is becoming increasingly popular in the United States. Drinking water is filtered to remove both organic and inorganic contaminants. The objective of this study was to evaluate the use of granular activated carbon from nutshells (almond, English walnut, pecan) in a POU water filtration system to determine its effectiveness in removing select, potentially toxic metal ions, namely, copper (Cu²⁺), lead (Pb²⁺) or zinc (Zn²⁺) found in drinking water. The nutshell-based carbon system was designated ‘Envirofilter’ and was compared to four commercial POU systems with brand names of BRITA, Omni Filter, PŪR and Teledyne Water Pik. Eight prototype ‘Envirofilters’, consisting of individual or binary mixtures of carbons made from acid-activated almond or pecan shells and steam-activated pecan or walnut shells were constructed and evaluated for adsorption of the three metal ions. The results indicated that a binary mixture of carbons from acid-activated almond and either steam-activated pecan or walnut shells were the most effective in removing these metals from drinking water of all the POU systems evaluated. Binary mixtures of acid-activated almond shell-based carbon with either steam-activated pecan shell- or walnut shell-based carbon removed nearly 100% of lead ion, 90–95% of copper ion and 80–90% of zinc ion. Overall the performance data on the ‘Envirofilters’ suggest that these prototypes require less carbon than commercial filters to achieve the same metal adsorption efficiency and may also be a less expensive product.

Keywords: Granular Activated Carbon, Drinking Water Filtration; Point-of-Use Water Filter, Pecan Shell, Almond Shell, English Walnut Shell, Copper, Lead, Zinc

Notes: highly cited

? Cho, M., Chung, H., Choi, W. and Yoon, J. (2004), Linear correlation between inactivation of E. coli and OH radical concentration in TiO₂ photocatalytic disinfection. Water Research, 38 (4), 1069-1077.

Full Text: 2004\Wat Res38, 1069.pdf

Abstract: The biocidal action of the TiO2 photocatalyst has been now well recognized from massive experimental evidences, which demonstrates that the photocatalytic disinfection process could be technically feasible. However, the understanding on the photochemical mechanism of the biocidal action largely remains unclear. In particular, the identity of main acting photooxidants and their roles in the mechanism of killing microorganisms is under active investigation. It is generally accepted that reactive oxygen species (ROS) and OH radicals play the role. The aim of this study is to deter-mine how the OH radical, acting either independently or in collaboration with other ROS, is quantitatively related to the inactivation of E coli. The steady-state concentrations of OH radicals ([.OH](ss)) in UV-illuminated TiO2 suspensions could be quantified from the measured photocatalytic degradation rates of p-chlorobenzoic acid (a probe compound) and its literature bimolecular rate constant with OH radicals. The results demonstrated an excellent linear correlation between [.OH](ss) and the rates of E coli inactivation, which indicates that the OH radical is the primary oxidant species responsible for inactivating E coli in the UV/TiO2 process. The CT value of OH radical for achieving 2 log E coli inactivation was initially found to be 0.8 x 10(-5) mg min/l, as predicted by the delayed Chick-Watson model. Although the primary role of OH radicals in photocatalytic disinfection processes has been frequently assumed, this is the first quantitative demonstration that the concentration of OH radicals and the biocidal activity is linearly correlated. (C) 2003 Elsevier Ltd. All rights reserved.

Keywords: TiO², E. coli, Photocatalysis, OH Radical, ROS (reactive oxygen species), Bactericidal Activity, Aqueous Suspensions, Water, Kinetics, Degradation, Ozone

Jensen-Spaulding, A., Shuler, M.L. and Lion, L.W. (2004), Mobilization of adsorbed copper and lead from naturally aged soil by bacterial extracellular polymers. Water Research, 38 (5), 1121-1128.

Full Text: W\Wat Res38, 1121.pdf

Abstract: Sorption of pollutants is a dominant phase transfer process affecting the fate and transport of metals through the subsurface. The movement of contaminants is retarded by sorption to the stationary subsurface porous media and can seriously hinder remediation efforts. Research has shown that the binding of adsorbed metals becomes more pronounced the longer the contaminant is in the subsurface and the release rates of aged metal contaminants have not received the research attention given to freshly added metals in laboratory studies. Metal release rates are also influenced by the presence of dissolved ligands that compete with mineral soil surfaces by providing binding sites. Dissolved organic matter such as bacterial extracellular polymers are common in natural soil solutions and the metal binding properties of bacterial polymers are well established. Therefore, binding of metals to dissolved biopolymers may result in mobilization of an adsorbed metal. This is important for cases where the metals are assumed to be relatively immobile such as in the case of land applied biosolids. In addition, naturally occurring adherent bacteria commonly produce extracellular polymers and thus may modify the bioavailability of meal contaminants at the point of their attachment. In this study samples from three sites, one a land applied sludge test site, were used to investigate the ability of bacterial extracellular polymers to release metals from soils with long-term exposures. The presence of  200 mg/L bacterial extracellular polymer was found to increase the short-term (less than 350 h) release of Cu and Pb by a factor of 2–4-fold.

Keywords: Adsorption, Bacteria, Copper, Extracellular Polymer, Lead, Sludge

Balci, S. (2004), Nature of ammonium ion adsorption by sepiolite: Analysis of equilibrium data with several isotherms. Water Research, 38 (5), 1129-1138.

Full Text: W\Wat Res38, 1129.pdf

Abstract: Adsorption isotherms for an ammonium ion–sepiolite system have been established for initial ammonium ion solution concentrations in the range of 8.32–388.06 mmol NH₄⁺/L (150–7000 ppm). The change of the ‘g sepiolite/mL solution’ ratios from 1/10 to 1/70 caused an increase in the adsorption from 1.82 to 3.70 mmol NH₄⁺/g for the average particle size of 2.8 mm. The equilibrium data were fitted to ‘general-purpose isotherms’ and ‘first-order adsorption model’, and the adjustable parameters of the isotherms were estimated by nonlinear least-squares analysis. Langmuir and Freundlich models were found insufficient to explain the adsorption equilibrium, while Langmuir–Freundlich and Tooth isotherms explained the data well. Goodness of fit increased with the increased sepiolite quantity in the treated suspension.

Keywords: Ammonium Removal, Sepiolite, Adsorption Isotherm

Meng Chun, S. Chugchun, Guo Y.H., Shi, X.A., Cheng, J.F. and Yan, F. (2004), Study on characteristics of biocometabolic removal of omethoate by the Aspergillus spp. Water Research, 38 (5), 1139-1146.

Full Text: W\Wat Res38, 1139.pdf

Abstract: A strain Aspergillus spp. F1 which could effectively metabolized omethoate was screened out in this study. F1 tended to form granula with diameter 4–5 mm after 5 days culture in shaker. The pH range from 4.5 to 6.5 was the suitable pH range for growth and metabolism of Aspergillus spp. F1. The maximum omethoate removal rate was about 3.0 mg/(h L), and the removal fraction of omethoate reached 90% after 8 days culture when initial concentrations of omethoate were not more than 2000 mg/L in medium. There was no obvious relativity between cell growth and cometabolism of omethoate. Starch was the best carbon source for omethoate removal and the result after 3 days reached 56.6% removal. F1 could use omethoate to metabolize as single nitrogen or phosphate source. The residual fragments in medium after treatment with the Aspergillus spp. F1 were determined by gas chromatography–mass spectrometry. The analysis results showed that only fragment o, o, s, -trimethyl phosphorothioate (TEP) containing phosphorus was available and the fragment containing nitrogen was consumed by F1 thoroughly in culture process. But no accumulations of TEP were observed in the omethoate bioremediation process. F1 could effectively remove omethoate in complex nutritional environment safely.

Keywords: Aspergillus spp. F1, Omethoate, Biocometabolic Removal, Phosphorus Source, Nitrogen Source, Nontoxic Fragments

Min, S.H., Han, J.S., Shin, E.W. and Park, J.K. (2004), Improvement of cadmium ion removal by base treatment of juniper fiber. Water Research, 38 (5), 1289-1295.

Full Text: W\Wat Res38, 1289.pdf

Abstract: Juniper is a small-diameter underutilized lignocellulosic material. We evaluated the efficacy of base-treated juniper fiber (BTJF) for cadmium (Cd²⁺) sorption and the viability of juniper fiber as a sorbent for removing Cd²⁺ from water. Fourier transform infrared spectroscopy analysis indicated that carboxylate ion is a major functional group responsible for Cd²⁺ sorption. The apparent ideal sodium hydroxide concentration for base treatment is approximately 0.5 M. A batch sorption isotherm test showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model. After base treatment, the maximum Cd²⁺ sorption loading, Q_max, was greatly improved (9.18–29.54 mg/g), despite a decrease in specific surface area. A pseudo-second-order kinetic model fitted well for the sorption of Cd²⁺ onto BTJF. Initial metal ion concentration and treatment alkalinity were found to be major parameters influencing the kinetics of the sorption reaction. As a result of its strong ability to bind cadmium and its faster kinetics in low concentration, BTJF could be an inexpensive and efficient sorbent for removing heavy metals from stormwater runoff.

Keywords: Cadmium, Juniper, Saponification, Fourier Transform Infrared (FTIR) Spectroscopy, Isotherm, Kinetics

Zeng, L., Li, X.M. and Liu, J.D. (2004), Adsorptive removal of phosphate from aqueous solutions using iron oxide tailings. Water Research, 38 (5), 1318-1326.

Full Text: W\Wat Res38, 1318.pdf

Abstract: This study explored the feasibility of utilizing industrial waste iron oxide tailings for phosphate removal in laboratory experiments. The experimental work emphasized on the evaluation of phosphate adsorption and desorption characteristics of the tailing material. The adsorption isotherm, kinetics, pH effect and desorption were examined in batch experiments. Five isotherm models were used for data fitting. The three-parameter equations (Redlich–Peterson and Langmuir–Freundlich) showed more applicability than the two-parameter equations (Freundlich, Langmuir and Temkin). A modified equation for calculation of the separation factor using the Langmuir–Freundlich equation constants was developed. The initial phosphate adsorption on the tailings was rapid. The adsorption kinetics can be best described by either the simple Elovich or power function equation. The phosphate adsorption on the tailings tended to decrease with an increase of pH. A phosphate desorbability of approximately 13–14% was observed, and this low desorbability likely resulted from a strong bonding between the adsorbed PO₄^3- and iron oxides in the tailings. Column flow-through tests using both synthetic phosphate solution and liquid hog manure confirmed the phosphate removal ability of the tailings. Due to their low cost and high capability, this type of iron oxide tailings has the potential to be utilized for cost-effective removal of phosphate from wastewater.

Keywords: Phosphate Removal, Iron Oxide Tailings, Adsorption, Isotherm, Kinetics

Kristian Stevik, T., Aa, K., Ausland, G. and Hanssen, J.F. (2004), Retention and removal of pathogenic bacteria in wastewater percolating through porous media: A review. Water Research, 38 (6), 1355-1367.

Full Text: W\Wat Res38, 1355.pdf

Abstract: Properly designed biological filters or infiltration systems have the capacity to significantly reduce effluent concentrations of pathogenic microorganisms in wastewater. The retention and elimination of microbial cells in biological wastewater filter systems is influenced by several factors. In this review, these factors are discussed. Immobilization of microbial cells moving through a porous media is influenced by mechanisms such as physical straining as well as adsorption to porous media. The grain size of porous media and bacterial cell size are important factors affecting the straining of bacteria, as are the hydraulic loading rate or the extent of clogging layer development in the filter. Adsorption of cells to the porous media is influenced by the content of organic matter, degree of biofilm development, and electrostatic attraction due to ion strength of the solution or electrostatic charges of cell- and particle surfaces. The rate of inactivation of pathogenic microorganisms, in adsorbed or liquid phases, has been shown to be affected by abiotic and biotic factors such as moisture content, pH, temperature, organic matter, bacterial species, predation, and antagonistic symbiosis between microorganisms in the system. (C) 2004 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Contaminated Sandy Aquifer, Escherichia-Coli, Facilitated Transport, Fecal Streptococci, Filtration Theory, Growth-Conditions, Infiltration, Pathogenic Bacteria, Porous Media, Pseudomonas-Fluorescens, Purification, Solid-Surfaces, Surface Characteristics, Unsaturated Soil Columns, Wastewater

? Maine, M.A., Sune, N.L. and Lagger, S.C. (2004), Chromium bioaccumulation: comparison of the capacity of two floating aquatic macrophytes. Water Research, 38 (6), 1494-1501.

Full Text: 2004\Wat Res38, 1494.pdf

Abstract: The capacity of Salvinia herzogii and Pistia stratiotes to remove Cr(III) from water and their behaviour at different Cr(III) concentrations were studied in outdoor experiments. Cr distribution in aerial parts and roots with time and the possible mechanisms of Cr uptake were analyzed. Both macrophytes efficiently removed Cr from water at concentrations of 1, 2, 4 and 6 mg Cr L^-1. S. herzogii was the best adapted species. At a greater initial concentration, greater bioaccumulation rates were observed. Root Cr uptake was a rapid process that was completed within the first 24 h. Cr uptake through direct contact between the leaves and the solution is the main cause of the increase of Cr in the aerial parts, Cr being poorly translocated from the roots to the aerial parts. Both mechanisms were fast processes. The Cr uptake mechanism involves two components: a fast component and a slow one. The former occurs mainly due to the roots and leaves adsorption and is similar for both species. The slow component is different for each species probably because in P. stratiotes a Cr precipitation occurs induced by the roots. (C) 2004 Elsevier Ltd. All rights reserved.

Keywords: Accumulation, Adsorption, Azolla-Filiculoides, Cadmium Uptake, Chromate, Chromium Bioaccumulation, Floating Aquatic Macrophytes, Heavy-Metals, Hyacinth, Pistia Stratiotes, Plants, Reduction, Salvinia Herzogii, Uptake Mechanism, Waste-Water Treatment, Water Pollution, Wetlands

Solbrå, S., Allison, N., Skei, J., Waite, S. and Mikhalovsky, S. (2004), Deploying a metal adsorbent in situ: A technique for indicating bioavailable Cd(II) in marine waters. Water Research,