Personal Research Database

? Lin, S.H. and Wu, C.L. (1996), Removal of nitrogenous compounds from aqueous solution by ozonation and ion exchange. Water Research, 30 (8), 1851-1857.

Full Text: 1996\Wat Res30, 1851.pdf

Abstract: Experiments were conducted to investigate the ammonia, nitrite and nitrate removal from aqueous solution using ozonation and ion exchange. The operating variables of the combined ozonation and ion exchange processes include the pH, initial concentration of nitrogenous compounds and flow rate of aqueous solution. The effects of those variables on the removal efficiencies of the nitrogeneous compounds by ozonation, or ion exchange or both were explored. Ozonation was found able to completely convert nitrite to nitrate. However its capability of ammonia removal is much limited. The anionic and cationic ion exchange resins were able to efficiently remove nitrate and residual ammonia. An optimal operating range of OH for ammonia removal by the combined ozonation and ion exchange was obtained. However, removal of nitrite and/or nitrate by combined ozonation and ion exchange was found to be relatively insensitive to pH. It was observed that the combined process is capable of efficiently maintaining the nitrogeneous compounds in the aqueous solution at very low concentration levels. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Nitrogeneous Compound Removal, Ozonation, Ion Exchange, Ammonia, Water

Huang, C. and Huang, C.P. (1996), Application of Aspergillus oryzae and Rhizopus oryzae for Cu(II) removal. Water Research, 30 (9), 1985-1990.

Full Text: W\Wat Res30, 1985.pdf

Abstract: Biosorption of copper(II) by the untreated and acid-treated fungal biomass has been studied in both batch and column modes. Two species, Aspergillus oryzae and Rhizopus oryzae, were used in this study. A. oryzae mycelia (undergoing acid-washing) exhibit a clear advantage in Cu(II) removal, compared with other adsorbents. The acid-washing process can strongly enhance the adsorption capacity for A. oryzae mycelia. However, acid-washing does not alter the metal adsorption capacity of R. oryzae mycelia. The result indicates that acid-washing is not only a pretreatment step but also a regeneration step in the heavy metal removal process. These dual purposes, therefore, give the acid-washing biomass an indication of successful prospect.

Cultivating A. oryzae in pellet form is an effective means of mycelium immobilization. The method established in this study provides the high-yield, uniformly-sized particles (2-3 mm in diameter), which are effective in solid-liquid separation. This pellet column can completely remove metals before breakpoint. After the breakpoint, a significant amount of Cu(II) removal over a long period has been observed. This is thought to be the result of intracellular uptake. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Fungi, Copper, Adsorption, Aspergillus oryzae, Rhizopus Oryzae, Heavy Metal, Immobilization, Metal-Ions, Biomass, Uranium

Ning, Z., Kennedy, K.J. and Fernandes, L. (1996), Biosorption of 2,4-dichlorophenol by live and chemically inactivated anaerobic granules. Water Research, 30 (9), 2039-2044.

Full Text: W\Wat Res30, 2039.pdf

Abstract: Equilibrium sorption isotherms and sorption kinetics of 2,4-dichlorophenol (2,4-dCP) on live and chemically inactivated anaerobic granules were investigated using batch serum bottle tests. A general metabolic inhibitor, sodium azide, was used to inactivate the biological activity of the anaerobic biomass. Experimental results showed that the difference in the biosorption of live and chemically inactivated anaerobic granules were not significant, suggesting that anaerobic biosorption is mainly a physical-chemical process and that metabolically mediated diffusion in the process is negligible. (C) 1996 Elsevier Science Ltd. All rights reserved.

Keywords: 2,4-dichlorophenol, Biosorption, Anaerobic, Granules, Sludge

Walley, W.J. and Hawkes, H.A. (1996), A computer-based reappraisal of the biological monitoring working party scores using data from the 1990 river quality survey of England and Wales. Water Research, 30 (9), 2086-2094.

Full Text: W\Wat Res30, 2086.pdf

Abstract: The policies and procedures adopted by the Biological Monitoring Working Party in developing its score system are summarised. The conceptual basis of the reappraisal is described and then formulated mathematically. The analysis is based on some 17,000 biological samples and covers 85 families. The results are expressed in terms of derived scores which mirror the scores allocated to the families by the BMWP. Some of the differences between the derived and original scores are quite substantial and are shown to relate to policies and practices adopted by the Working Party. It is argued that the derived scores offer a more realistic representation of the families’ sensitivities to pollution than do the BMWP scores. The most significant differences are discussed in relation to their likely causes and are shown to be consistent with expectations. It is concluded that the system’s poor performance in some recent tests may be explained by these findings and that corrective action could improve performance.

Keywords: River, Quality, Pollution, Classification, Monitoring, Biology, Benthic, Invertebrates, Biotic Indices

Meng, X.G. and Letterman, R.D. (1996), Modeling cadmium and sulfate adsorption by Fe(OH)₃/SiO₂ mixed oxides. Water Research, 30 (9), 2148-2154.

Full Text: W\Wat Res30, 2148.pdf

Abstract: Adsorption of cadmium and sulfate in a mixed Fe(OH)₃/SiO₂ system was studied using the triple-layer model. The uptake of H₄SiO₄ dissolved from the SiO₂ particles was considered in modeling the cation and anion adsorption. The mixed oxides were formed with a range of Fe(OH)₃: SiO₂ ratios by controling the precipitation of ferric hydroxide in a suspension of fumed silica (Cab-O-Sil). Observation of the micromorphology of the mixed oxides by transmission electron microscopy showed that Fe(OH)₃ formed separately from the SiO₂ particles, therefore, an independent oxide model was used to simulate cation and anion adsorption. In this model Cd adsorption occurred on separate Fe(OH)₃ and SiO₂ surfaces, When the pH was lower than 8, Fe(OH)₃ dominated Cd adsorption in the mixed system. Sulfate adsorption on the independent Fe(OH)₃ surface was modeled for the mixed oxide system because no sulfate was adsorbed by the SiO₂ surface at pH > 4. The uptake of H₄SiO₄ reduced sulfate adsorption, but it had a negligible effect on cadmium absorption due to a combination of sorbate competition and electrostatic interactions. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Adsorption, Cadmium, Sulfate, Oxide, Model, Surface Complex, Amorphous Iron Oxyhydroxide, Surface-Ionization, Anion Adsorption, Water Interface, Goethite, Complexation, Ions

Smith, E.H. (1996), Uptake of heavy metals in batch systems by a recycled iron-bearing material. Water Research, 30 (10), 2424-2434.

Full Text: W\Wat Res30, 2424.pdf

Abstract: An iron-bearing material deriving from surface finishing operations in the manufacturing of cast-iron components demonstrates potential for removal of heavy metals from aqueous waste streams. Batch isotherm and rate experiments were conducted for uptake of cadmium, zinc and lead. In the pH range of 4-7, the iron sorbent had the highest capacity, on a mass-per-mass basis, for lead followed by zinc and cadmium. As anticipated, solution pH has a notable impact on metal removal, while ionic background and initial metal concentration exhibited a lesser impact on adsorptive behavior. Metal surface complexation with a developing oxide layer is postulated as the principal mechanism of heavy metal removal. Batch adsorption kinetics are quite rapid, with 90% or more of metal uptake occurring within the first 5-10 h of reaction for powdered fines. Larger, granular-sized particles exhibited a longer, slower approach toward the equilibrium position. Surface complexation as well as semi-empirical equilibrium and rate models provided a useful description of experimental phenomena in that conditional trends were reflected in the estimated values of the model coefficients. Given the availability and comparable metal uptake capacity of the recycled iron sorbent to natural metal oxides and some commercial adsorbents, use of the iron-bearing material offers potential environmental and economic benefit for certain industrial pretreatment applications.

Keywords: Adsorption, Batch Kinetics, Heavy Metals, Industrial Pretreatment, Iron Fines, pH Effects, Recycling Reuse, Cadmium Adsorption, Oxyhydroxide, Oxides, Model, Ions, Removal, Lead

Navarro, R.R., Sumi, K., Fujii, N. and Matsumura, M. (1996), Mercury removal from wastewater using porous cellulose carrier modified with polyethyleneimine. Water Research, 30 (10), 2488-2494.

Full Text: W\Wat Res30, 2488.pdf

Abstract: An adsorbent for heavy metal was synthesized by introducing polyethyleneimine (PEI) into porous cellulose carriers. Evaluations of synthesis results and adsorbent properties were conducted. Elementary analysis of the adsorbent revealed extensive crosslinking of PEI with the modified matrix. Batch adsorption tests showed the ability of cell-PEI to selectively remove mercury even at acidic regions. At low concentration ranges, mercury adsorption by cell-PEI can be interpreted by the Langmuir isotherm. With this model, an adsorbent capacity and Hg-ligand stability constant of approximately 288.0 mgg^-1 and 12.9 lmg^-1, respectively, were obtained. From adsorption rate experiments, diffusivity of Hg in the carrier was found to be approximately equal to 7.30×10^-14 m²s^-1. Extensive crosslinking of PEI chains that restricts ligand mobility was cited as the foremost factor contributing to these observed properties.

Keywords: Adsorption, Crosslinking, Mercury, Polyethyleneimine, Porous Cellulose Carrier

Benjamin, M.M., Sletten, R.S., Bailey, R.P. and Bennett, T. (1996), Sorption and filtration of metals using iron-oxide-coated sand. Water Research, 30 (11), 2609-2620.

Full Text: W\Wat Res30, 2609.pdf

Abstract: Iron oxides are good adsorbents for uncomplexed metals, some metal-ligand complexes, and many metal oxyanions. However, the adsorbent properties of these oxides are not fully exploited in wastewater treatment operations because of difficulties associated with their separation from the aqueous phase. This paper describes experiments in which iron oxides were coated onto the surface of ordinary filter sand, and this composite media was used in a fixed bed configuration for simultaneous filtration of particulate matter and sorption of dissolved metals. The process was successful in removing uncomplexed and ammonia-complexed cationic metals (Cu, Cd, Pb, Ni, Zn), as well as some oxyanionic metals (SeO₃, AsO₃), from simulated and actual waste streams over a wide range of metal concentrations. The adsorbent was stable during backwashing and regeneration operations, releasing most metals quantitatively; the exception was AsO₃, which was not efficiently recovered by regeneration with either acid or base. The composite media is inexpensive to prepare and could serve as the basis of a useful metal removal and possibly metal recovery process in a variety of settings. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Adsorption, Iron Oxides, Metals, Coated Sand, Bearing Wastes, Adsorption, Removal, Oxyhydroxide, Ions

Smith, E.H., Lu, W.P., Vengris, T. and Binkiene, R. (1996), Sorption of heavy metals by Lithuanian glauconite. Water Research, 30 (12), 2883-2892.

Full Text: W\Wat Res30, 2883.pdf

Abstract: Adsorption equilibria are evaluated for Cd(II), Pb(II) and Zn(II) on a sample of pass 200 mesh Lithuanian glauconite using two different experimental/analytical approaches. First, the impacts of total metal concentration, ionic strength and pH on adsorption capacity are quantified in terms of the Freundlich isotherm equation for isotherms conducted at a single initial pH value. Relative adsorption capacity for the metals was in the order Pb > Cd > Zn. Secondly, pH effects and sorption mechanisms were examined more closely using the triple layer-surface complexation model to describe pH-adsorption edges. Although glauconite is a complex clay mineral, a single site approach provided a satisfactory description for many of the cases studied. Discrepancies between model simulations and experimental data were observed for some instances involving large changes in ionic strength or sorbate-to sorbent ratio when using adsorption reactions and equilibrium constants evaluated for a baseline case. Analysis of the possible contributions of multi-site adsorption, cationic exchange, mineral dissolution and desorption phenomena are required to more accurately characterize metal uptake by glauconite.

Keywords: Adsorption, Montmorillonite, Removal, Models, Cu²⁺, Adsorption, Cadmium, Glauconite, Lead, Surface Complexation, Triple-Layer Model, Zinc

Mollah, A.H. and Robinson, C.W. (1996), Pentachlorophenol adsorption and desorption characteristics of granular activated carbon. I. Isotherms. Water Research, 30 (12), 2901-2906.

Full Text: W\Wat Res30, 2901.pdf

Abstract: The adsorption/desorption of pentachlorophenol (PCP) with Calgon F300 granular activated carbon (GAG) was studied and modelled. A modified Radke-Prausnitz (1972) isotherm model, incorporating a temperature- and pH-dependent proportionality constant, was found to best describe the observed PCP adsorption and desorption. The modified isotherm is valid in the ranges 4 less than or equal to pH less than or equal to 11 and 10 less than or equal to T less than or equal to 60°C. The activation energy of PCP adsorption was calculated to be 5.2 kJ/mol. At 30°C, PCP adsorbed strongly, and the rate of subsequent desorption was very low. However, the amount of PCP desorbed could be increased significantly by increasing the temperature to 60°C. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Adsorption, Desorption, Isotherm, Pentachlorophenol, Granular Activated Carbon, Microbial Regeneration Process, Organic Solutes, Capacity, Oxygen

Mollah, A.H. and Robinson, C.W. (1996), Pentachlorophenol adsorption and desorption characteristics of granular activated carbon. II. Kinetics. Water Research, 30 (12), 2907-2913.

Full Text: W\Wat Res30, 2901.pdf

Abstract: The kinetics of pentachlorophenol (PCP) adsorption/desorption with Calgon F300 granular activated carbon (GAC) was studied. A previously-developed model of GAC adsorption/desorption kinetics was applied to the case of PCP for both batch and continuous plug-flow liquid conditions. The model predictions were found to be in good agreement with the experimental observations.

Keywords: Adsorption, Desorption, Pentachlorophenol, Granular Activated Carbon, Kinetic Model, Microbial Regeneration Process

Gabaldón, C., Marzal, P., Ferrer, J. and Seco, A. (1996), Single and competitive adsorption of Cd and Zn onto a granular activated carbon. Water Research, 30 (12), 3050-3060.

Full Text: W\Wat Res30, 3050.pdf

Abstract: Single and competitive adsorption of cadmium and zinc onto granular activated carbon DARCO 12-20 mesh has been investigated. This activated carbon has been shown as an effective adsorbent for both metals. Cadmium and zinc removals increased with pH and decreased with molar metal/carbon ratio. Surface precipitation phenomena have been detected for the higher pHs and molar ratios. The adsorption process has been modelled on the surface complexation Triple Layer Model (TLM). For this purpose, the amphoteric nature of the activated carbon has been studied. Single metal adsorption data have been used to calibrate TLM parameters. A dependence of the adsorption constants on pH and molar metal/carbon ratio has been observed and a correlation for log K_ads has been determined. In the competitive system, the removal efficiency of the activated carbon decreased for both metals. The TLM model, using surface complexation constants determined from single adsorption experiments, successfully predicted cadmium and zinc removal from the two metalsolutions.

Keywords: Oxide-Water Interface, Ionic-Strength, Metal, Sorption, Systems, Model, Adsorption, Surface Complexes, Heavy Metals, Activated Carbon, Triple-Layer Model

Zhou, J.L., Rowland, S.J., Mantoura, R.F.C. and Lane, M.C.G. (1997), Desorption of tefluthrin insecticide from soil in simulated rainfall runoff systems: Kinetic studies and modeling. Water Research, 31 (1), 75-84.

Full Text: W\Wat Res31, 75.pdf

Abstract: The sorption and subsequent desorption from soil particles, of tefluthrin, a widely used soil-active pyrethroid insecticide, were studied in a simulated rainfall runoff system. Experimentation was facilitated by use of the ¹⁴C-labelled compound. The desorption of such highly hydrophobic organic compounds from soils has rarely been reliably determined previously. Sorption results showed that the partition coefficients (K_p and K_oc) were determined with good precision; although the resultant coefficients were shown to be underestimates of true adsorption to soil due to non-attainment of true equilibrium and the presence of colloidal material in the aqueous phase supernatants analysed. Once the adsorption slurries were diluted (30 mi of aqueous phase to 3.51) to simulate transport of soil to a larger water body after heavy rainfall, kinetic studies, using a centrifugation method, indicated that the soil phase concentration decreased once more, whilst at the same time a biphasic re-equilibration process occurred in the aqueous phase. A direct particle counting method was used to rapidly and reproducibly measure desorption of ¹⁴C-tefluthrin from soil under contrasting experimental conditions. Initial re-equilibration was shown to be rapid when soil-to-water ratios were changed significantly, temperature having a pronounced effect on this desorption. The results are important for the accurate modelling of tefluthrin behaviour in the environment.

Keywords: Pyrethroid Insecticide, Tefluthrin, Soil, Desorption, Kinetics, Modeling, Synthetic Pyrethroid Insecticides, Hydrophobic Organic-Compounds, Adsorption-Desorption, Mineral Particles, Sorption, Pesticides, Temperature, Pollutants, Partition, Sediments

Jain, C.K. and Ram, D. (1997), Adsorption of lead and zinc on bed sediments of the River Kali. Water Research, 31 (1), 154-162.

Full Text: W\Wat Res31, 154.pdf

Abstract: The adsorption characteristics of the bed sediments collected from the River Kali in western Uttar Pradesh, India, have been studied for the uptake of lead and zinc ions. The parameters controlling the uptake, viz. initial metal ion concentration, the solution pH, sediment dose, contact time and particle size have been evaluated. The adsorption of metal ions increases with increasing initial metal ion concentration. The adsorption of the two metal ions on the bed sediments follows two phases: a linear phase of adsorption and then a quasi-equilibrium state (almost flat plateau). The quasi-equilibrium state was attained within 45 min for both the metal ions. It is observed that the extent of adsorption increases with the increase of pH of the solution and metal ion concentration decreases with increase in pH value. Further, the adsorption of metal ions increases with increasing adsorbent doses and decreases with adsorbent particle size. The geochemically important elements such as Fe and Mn have also been determined in various grain size fractions of the sediments and correlated with the adsorption of metal ions. The adsorption data of the two metal ions has also been analysed with the help of the Langmuir and Freundlich models to evaluate the mechanistic parameters associated with the adsorption process, viz. monolayer capacity and sorption intensity.

Walley, W.J. and Hawkes, H.A. (1997), A computer-based development of the biological monitoring working party score system incorporating abundance rating, site type and indicator value. Water Research, 31 (2), 201-210.

Full Text: W\Wat Res31, 201.pdf

Abstract: A method of deriving BMWP (Biological Monitoring Working Party) scores and indicator values that incorporates the effects of abundance rating and site type is presented. This is an extension of earlier work by the authors, which reappraised overall BMWP family scores using biological data from the 1990 River Quality Survey of England and Wales. The method is only briefly explained but its formulation in mathematical terms is fully documented. Full details are given of the overall, site-related and site-abundance-related derived scores and indicator values of 34 selected families. New definitions of average score per taxon (ASPT) based on the derived scores and indicator values are presented and the potential impact of these on existing BMWP site scores and ASPTs is briefly examined via two examples. Some interesting variations in the derived scores with respect to site type and abundance rating are noted and explanations of these are given from an ecological point of view. It is concluded that the method described offers a means of significantly improving the reliability and hence utility of the BMWP score system.

? Mak, F.T., Zele, S.R., Cooper, W.J., Kurucz, C.N., Waite, T.D. and Nickelsen, M.G. (1997), Kinetic modeling of carbon tetrachloride, chloroform and methylene chloride removal from aqueous solution using the electron beam process. Water Research, 31 (2), 219-228.

Full Text: 1997\Wat Res31, 219.pdf

Abstract: An innovative treatment process using high energy electrons has been shown to be effective for the destruction of various toxic (regulated) organic chemicals. This paper presents data for the destruction of chlorinated methanes, carbon tetrachloride, chloroform and methylene chloride in treated groundwater. The studies were conducted at pilot scale, using a 75 kW electron beam at a how rate of 0.38 m(3) min(-1) This study examined the effect of solute concentration and total alkalinity on removal efficiency. A kinetic model was used to describe the results of single solute experiments of the three chlorinated methanes. These model predictions were then compared to experimental results and showed a varying degree of predictability for the three compounds. These calculations suggest that the initial reactions which eventually lead to the mineralization of the three chlorinated methanes result primarily from aqueous electron initiated reactions. The subsequent reaction between O-2 and the carbon centered radicals with the formation of alkyl peroxides also appears important for their ultimate decomposition. Copyright (C) 1996 Elsevier Science Ltd.

Keywords: E-Beam, Kinetic Modeling, Carbon Tetrachloride, Chloroform And Methylene Chloride, Hydroxyl Radicals, Rate Constants, Energy, Irradiation, Benzene, Oxygen, Scale

Banerjee, K., Cheremisinoff, P.N. and Cheng, S.L. (1997), Adsorption kinetics of o-xylene by flyash. Water Research, 31 (2), 249-261.

Full Text: W\Wat Res31, 249.pdf

Abstract: Relatively limited information is available regarding the kinetics of sorption of organic compounds from solution onto flyash. For this reason, a detailed study of the kinetics of sorption of o-xylene on flyash was conducted in a controlled batch system. The effects of solute concentration, particle size of the adsorbent and temperature on the adsorption rate were investigated. The results of this research demonstrate that the adsorption reaction can be approximated to first-order reversible kinetics. A significant correlation was observed between the rate of adsorption and the inverse of the square of the particle diameter. An examination of thermodynamic parameters shows that the adsorption of o-xylene by flyash is an exothermic process and is spontaneous at the temperature investigated. Activation energies for the sorption process ranged between 3.1 and 4.3 kcal/mol. The rate at which o-xylene is adsorbed onto flyash was found to be controlled by the diffusion process.

Keywords: Flyash, Adsorption, Kinetics, Rate Constant, O-Xylene, Diffusion, Activation Energy, Free Energy, Differential Heat of Adsorption, Entropy, Organic Contaminants, Aqueous-Solutions, Waste-Water, Ash, Sorption, Removal, Coal

Mellah, A. and Chegrouche, S. (1997), The removal of zinc from aqueous-solutions by natural bentonite. Water Research,