Personal Research Database

Wang, X. and Leslie Grady, Jr., C.P. (1994), Comparison of biosorption isotherms for di-N-butyl phthalate by live and dead bacteria. Water Research, 28 (5), 1247-1251.

Full Text: W\Wat Res28, 1247.pdf

Abstract: Isotherms were determined for the sorption of di-n-butyl phthalate (DBP) on live and dead suspensions of Pseudomonas fluorescens IFO 12055. When isotherms were expressed in terms of the suspended solids concentration actually present in the sorption flasks, the dead biomass had an apparently higher affinity for DBP. However, when the loss of biomass due to cell lysis during autoclaving was considered, the isotherms on the two types of biomass were the same.

Keywords: Biosorption, Di-N-Butyl Phthalate, Hazardous Organic Pollutants, Water Partition-Coefficients, Microbial Biomass, Adsorption, Removal, Degradation, Desorption, Esters

Couillard, D. (1994), The use of peat in wastewater treatment. Water Research, 28 (6), 1261-1274.

Full Text: W\Wat Res28, 1261.pdf

Abstract: Peat has been widely used in the treatment of wastewaters. The potential of using peat in wastewater treatment is reviewed with special attention to the following topics: (i) the properties of peat; (ii) the pretreatment of peat; (iii) the principles involved in the removal of wastewater pollutants by peat; and (iv) the applications of peat to the removal of impurities from wastewater.

Keywords: Peat, Water Pollution Control, Waste-Water Treatment, Waste-Water, Waste-Water Systems, Filtration, Peat Beds, Oil, Hydrocarbons, Water Renovation, Water Treatment, Effluent Treatment, Diffusion-Model, Acid Dye, Removal, Adsorption, Runoff, Batch, Adsorbent, Nutrients

Mota, A.M., Pinheiro, J.P. and Gonçalves, M.L. (1994), Adsorption of humic acid on a mercury/aqueous solution interface. Water Research, 28 (6), 1285-1296.

Full Text: W\Wat Res28, 1285.pdf

Abstract: The adsorption on a mercury/water interface of a sample of humic acids from an Irish peat has been analyzed by a.c. voltammetry, using a hanging mercury drop electrode in an unstirred and/or stirred medium, at different pH values (pH = 2.5, 5 and 8) and two potential values (E =-0.5 and-0.9V), in order to have a better insight into the kinetics and equilibrium adsorption which may drastically affect the voltammetric signal in trace metal speciation of natural waters.

The results at pH 2.5 present a slower kinetic of adsorption but a higher coverage degree at the equilibrium when compared with pH 5 and/or 8 due to the charge of the molecules. At-0.5 V, close to the potential of zero charge, the kinetics of adsorption is discussed in terms of a diffusion mechanism, but at-0.9 V the experimental curves clearly show that the global adsorption process cannot be explained by a pure diffusion mechanism based on Frumkin isotherm.

Keywords: Humic Acid, Natural Waters, Adsorption Kinetics, Adsorption Equilibrium, Ac Voltammetry, Surface-Active Substances, Mercury Electrolyte Interface, Anodic-Stripping Voltammetry, Fulvic Substances, Fresh-Waters, Seawater, 2,3-Dimethylpyridine, Polarography, Kinetics, Colloids

? Logan, B.E., Alleman, B.C., Amy, G.L. and Gilbertson, R.L. (1994), Adsorption and removal of pentachlorophenol by white rot fungi in batch culture. Water Research, 28 (7), 1533-1538.

Full Text: 1994\Wat Res28, 1533.pdf

Abstract: The adsorption and removal of pentachlorophenol (PCP) by 12 species of white rot fungi is a function of species and culture conditions. In general, PCP adsorption to mycelia was very low, ranging from 0.01 to 0.05 g PCP g mycelium⁻¹ (dry wt basis) at 40 mg PCP l⁻¹, with no apparent corellation between species. after long pre-incubation periods (8–20 d), all species of fungi reduced PCP by > 50% within 12 days of PCP addition. Several species of fungi, including Phanerochaete chrysosporium, Trametes versicolor, and all four Ganoderma sp. removed > 50% of the PCP within 24 h, although the largest overall reduction of PCP (96%) was achieved by Inonotus rickii. PCP removal in 250 ml flasks by shallow (10 ml) cultures was greater than removal by deep (50 ml) cultures indicating that the ratio of surface area to volume of liquid media is an important factor in the extent of PCP removal by white rot fungi.

Keywords: Adsorption, Biodegradation, White Rot Fungi, Pentachlorophenol, Phanerochaete Chrysosporium, Suspended Cultures

? Karanfil, T., Schlautman, M.A. and Weber, Jr., W.J. (1994), Impacts of dissolved-oxygen on the sorption of humic substances and the subsequent inhibition of o-cresol uptake by granular activated carbon. Water Research, 28 (7), 1673-1678.

Full Text: 1994\Wat Res28, 1672.pdf

Abstract: The impacts of dissolved oxygen (DO) on the sorption of natural and model humic substances by granular activated carbon (GAC) were investigated. Among five substances tested, the sorptions of only two, polymaleic acid (PMA) and peat humic acid, were affected by the presence of DO. The uptake of the target compound o-cresol on virgin GAC and on GAC preloaded with PMA under oxic and anoxic conditions was also examined. The oxic and anoxic preloading conditions had similar effects on subsequent o-cresol reactions under both oxic and anoxic sorption conditions. A reduction of approximately 20% in o-cresol uptake observed under anoxic conditions by GAC preloaded under each condition is attributed to a decrease in the adsorption capacity of the GAC by preloading. In the presence of oxygen, however, an observed reduction of about 45% in o-cresol uptake by preloaded GAC appears to result from a combination of decreased adsorption and inhibited o-cresol polymerization.

Keywords: Activated Carbon, Adsorption, Chlorine, Dissolved Oxygen, Gac, Humic Acid, Humic Substances, O-Cresol, Organic-Matter, Oxidative Coupling, Oxygen, Phenols, Polymerization, Sorption, Transport

Smith, E.H. (1994), Bench-scale tests and modeling of adsorption of natural organic matter by activated carbon. Water Research, 28 (8), 1693-1702.

Full Text: W\Wat Res28, 1963.pdf

Abstract: Adsorption equilibria for activated carbon removal of natural organic matter (NOM) were obtained for a lake water, a leaf extract humic material and a sample from a monitoring well serving a municipal solid waste landfill. A multicomponent model incorporating ideal adsorbed solution theory (IAST) and a non-adsorbable fraction more accurately described equilibrium data for the overall isotherm than a Freundlich single component isotherm model, and adequately simulated isotherms for variable initial concentration of the water as represented by a lumped parameter. A methodology is described for estimating equilibrium parameters for multiple hypothetic components that requires fewer parameter searches and is thus less computationally demanding than some other modeling schemes using IAST. The acquired equilibrium information was subsequently used to calibrate a dynamic, fixed-bed model in accordance with bench-scale column data for the lake water. Rate parameters evaluated therein were used to predict breakthrough profiles in bench-scale columns of greater bed depth. Generally speaking, dynamic modeling which incorporated the multicomponent equilibrium approach provided more accurate description and prediction of NOM breakthrough profiles than a single component modeling scheme. The multicomponent approach was better able to simulate both the slow approach to exhaustion in the bed and the effects of changes in influent concentration. Although not fully representative of a full-scale system operating over a lengthy time period, the exercise gives insight into dynamic and modeling phenomena which may accompany seasonal variations in natural water quality.

Keywords: Activated Carbon, Adsorption Equilibria, Adsorption Kinetics, Hypothetical Components, Ideal Adsorbed Solution Theory, Lumped Parameters, Mathematical Modeling, Microcolumn, Seasonal Effects

Sorial, G.A., Papadimas, S.P., Suidan, M.T. and Speth, T.F. (1994), Competitive adsorption of VOCs and BOM-Oxic and anoxic environments. Water Research, 28 (9), 1907-1919.

Full Text: W\Wat Res28, 1907.pdf

Abstract: The effect of the presence of molecular oxygen on the adsorption of volatile organic compounds (VOCs) in distilled Milli-Q water and in water supplemented with background organic matter (BOM) is evaluated. Experiments are conducted under conditions where molecular oxygen is present in the test environment (oxic adsorption), and where oxygen is absent from the test environment (anoxic adsorption). Adsorption isotherms for tetrachloroethylene (PCE) and trichloroethylene (TCE) in Milli-Q water showed no impact of the presence of oxygen on their adsorption behavior, while adsorption isotherms for cis-1,2-dichloroethene (DCE) showed higher capacities under oxic conditions. VOC adsorption isotherms in BOM are conducted for three initial concentration sets of VOCs and two initial concentration sets of BOM. VOC isotherms collected under oxic and anoxic conditions in water supplemented with BOM showed that by keeping the initial concentration ratio of VOCs to BOM constant, the adsorption behavior of the VOC is very similar. VOC isotherms in BOM conducted under oxic conditions generally showed lower capacities than the anoxic isotherms. The ideal adsorbed solution theory (IAST) successfully predicted the VOCs anoxic adsorption isotherms in BOM. However, the IAST model did not predict the VOCs oxic adsorption isotherms in BOM. Analysis of the data was conducted using the isotherm parameters of the VOCs in Milli-Q water, and correlation parameters using a four fictive component approach for the BOM. The poor agreement between experimental data and model predictions obtained for the oxic isotherms is attributed to the presence of molecular oxygen which promotes conglomeration of BOM on the surface of carbon.

Keywords: Competitive Adsorption, Volatile Organic Compounds, Background Organic Matter, Oxygen, Activated Carbon, Synthetic Organics, Dissolved-Oxygen, Capacity, Gac, Isotherms

Chen, J.H, Lion, L.W., Ghiorse, W.C. and Shuler, M.L. (1995), Mobilization of adsorbed cadmium and lead in aquifer material by bacterial extracellular polymers. Water Research, 29 (2), 421-430.

Full Text: W\Wat Res29, 421.pdf

Abstract: The mobility of cationic trace metals, such as ph and Cd, in porous media can be severely limited by their adsorption at the solid/solution interface. The transport of metals can be enhanced by complexation with a ligand of ‘carrier’ that (i) is soluble in water and does not strongly sorb to surfaces, (ii) has a high metal binding affinity and (iii) is not readily altered in soil by chemical or biological reactions. Extracellular polymers of bacterial origin are plausible carriers for metals in soil or aquifer systems. Bacterial extracellular polymers occur naturally in groundwaters and some have well established metal binding properties. In this study, extracellular polymers from 13 bacterial strains, including five subsurface isolates, were screened for their ability to mobilize Pb and Cd adsorbed to an aquifer sand. Batch adsorption isotherms were employed to screen polymers for their effect on metal phase distribution. Air of the extracellular polymers tested reduced the linear distribution coeffients of Cd and Pb. Reductions in metal adsorption by over 90% were achieved at an extracellular polymer concentration of 10.6 mgl^-1 The sorption isotherm of a selected extracellular polymer indicated that it had a low affinity for the sand sorbent and suggested that the polymer would be mobile in the porous sand medium. The distribution coefficient of the polymer for the sand was not effected by the presence Cd at low concentrations. Independently determined distribution constants for Cd and extracellular polymer with the sand and the binding constant for Cd to polymer yielded reasonable estimates of the observed distribution of Cd in the presence of the extracellular polymer. Column experiments performed with Cd in the presence and absence of the selected extracellular polymer confirmed that application of polymer solutions can enhance metal mobility in porous media.

Keywords: Aquifer Material, Adsorption, Bacteria, Cadmium, Complexation, Extracellular Polymer, Facilitated Transport, Lead, Pseudomonas-Atlantica, Activated-Sludge, Transport, River, Water, Exopolysaccharide, Flocculation, Environment, Equilibrium, Adsorption

Notes: highly cited

Streat, M., Patrick, J.W. and Camporro Perez, M.J. (1995), Sorption of phenol and para-chlorophenol from water using conventional and novel activated carbons. Water Research, 29 (2), 467-472.

Full Text: W\Wat Res29, 467.pdf

Abstract: A comparative study of the sorption of phenol and p-chlorophenol from water has been performed using novel samples prepared by carbonisation and subsequent activation of straw and used rubber tyres as well as conventional activated carbons based on coal, coconut shell and wood. Pseudo-equilibrium sorption of phenol and p-chlorophenol obeys a Freundlich type adsorption isotherm of the form; q = k c(n) in the adsorbate concentration range 0-6 mmol l^-1. Measured values of k and n indicate that the sorption of phenol and p-chlorophenol onto active carbons derived from straw and used rubber tyres is almost identical to that for conventional activated carbons. The rate of adsorbate uptake has been measured and the sorption half-times lie in the range 1.4-15 min for phenol. The sorption kinetics of the straw and rubber tyre based carbons are likewise identical to conventional carbons based on coal and wood but appreciably faster than the coconut shell sample selected for comparison.

Keywords: Phenol, Para-Chlorophenol, Activated Carbon, Kinetics, Adsorption

Srivastava, S.K. and Tyagi, R. (1995), Competitive adsorption of substituted phenols by activated carbon developed from the fertilizer waste slurry. Water Research, 29 (2), 483-488.

Full Text: W\Wat Res29, 483.pdf

Abstract: A study of the competitive effects on the uptake of 4 substituted phenols on a carbonaceous adsorbent derived from fertilizer waste. Waste slurry from fertilizer plants in India has been converted to low-cost carbonaceous adsorbent material, which shows potential in scavenging toxic metal ions and phenols in industrial effluents. The results indicate that the rate of adsorption of the 4 substituted phenols decreases in the order 2,4,6-trinitrophenol, 4-nitrophenol, 4-chlorophenol, 1,3-Dihydroxybenzene. The observed data for the mutual suppression of equilibrium adsorption due to competition between substituted phenols are closer to the values predicted by a modified Langmuir model than to those of the Langmuir equations for bisolute systems. However, the actual degree of suppression is greater than model predictions for 1,3-Dihydroxybenzene and smaller than model predictions for 2,4,6-trinitrophenol, probably because some sites are inaccessible to 1,3-Dihydroxybenzene due to is electron donating nature.

Keywords: Competitive Adsorption, Activated Carbon, Substituted Phenols, Fertilizer Waste

Arambašić, M.B., Bjelić, S. and Subakov, G. (1995), Acute toxicity of heavy metals (copper, lead, zinc), phenol and sodium on Allium cepa L., Lepidium sativm L. and Daphnia magna st.: Comparative investigations and the practical applications. Water Research, 29 (2), 497-503.

Full Text: W\Wat Res29, 497.pdf

Abstract: The investigations of the effects of various heavy metal: Cu (as CuSO₄), Pb (as Pb(NO₃)₂) and Zn (as ZnSO₄), phenol and Na (as Na₂SO₄ and NaCl) concentrations on root length of onion bulbs (Allium cepa L.) and garden cress (Lepidium sativum L.), as well as on the survival rate of great water flea (Daphnia magna St.) showed varied sensitivity of the above test organisms. Based on IC50 Value (50% inhibitory concentration) for A. cepa L. and L. salivum L. and on LC₅₀ value for D. magna St., the acute toxicity of the tested substances decreased after a 48-hour exposition in the following order: A. cepa L.: Cu > Pb > Zn > phenol > Na₂SO₄ > NaCl; L. sativum L.: phenol > Cu > Pb > Zn > Na₂SO₄ > NaCl; D. magna St.: Cu > Zn > phenol > Pb > Na₂SO₄ > NaCl.

Keywords: Acute Toxicity, Ic50, Lc50, Copper, Lead, Zinc, Phenol, Sodium, Allium Cepa L, Lepidium Sativum L, Daphnia Magna St, Allium Test, Lepidium Test, Water-Toxicity Estimation, Chromosomal-Aberrations, Water, Products, Selenium, Cadmium, Growth, System, Fish

? House, W.A., Denison, F.H. and Armitage, P.D. (1995), Comparison of the uptake of inorganic phosphorus to a suspended and stream bed sediment. Water Research, 29 (3), 767-779.

Full Text: 1995\Wat Res29, 767.pdf

Abstract: Results are presented describing the influx of soluble reactive phosphorus (SRP) to a stream sediment in an outdoor experimental channel, a laboratory channel and in well-mixed suspensions. The kinetics of phosphorus uptake are modelled using several kinetic equations including the Elovich, Bangham, diffusion and first-order equation. The Elovich equation is found to describe best the SRP influx to both bed and suspended sediments. The relative contribution of abiotic and biotic processes in the outdoor experimental channel are considered together with estimates of the flux to the bed-sediment predicted from the results describing the kinetics in the laboratory channel. The sediment is characterized by mineralogy, size fractionation and wet-chemical analyses including total phosphorus, iron and calcium determinations as well as biologically available phosphorus (BAP) by the iron-oxide stripping method and the equilibrium phosphate concentration, EPC(0), calculated from sorption measurements. The kinetic results from this sediment illustrate the importance of suspended sediment in the fast uptake of SRP. This contrasts with the control of the influx of SRP to the bed-sediment in channels with low concentrations of suspended solids, caused by the rate-limiting diffusional transfer across the sediment-water interface.

Keywords: Phosphorus, Phosphate, Rivers, Sediments, Suspended Sediments, Water Quality, Eutrophication, Nutrients, Adsorption, Phosphate Release, Elovich Equation, Lake Sediment, Adsorption, River, Coprecipitation, Prediction, Sorption, Kinetics, Exchange

Su, M.C., Cha, D.K., Anderson, P.R. (1995), Influence of selector technology on heavy metal removal by activated sludge: Secondary effects of selector technology. Water Research, 29 (3), 971-976.

Full Text: W\Wat Res29, 971.pdf

Abstract: The purpose of this research is to compare the ability of metal removal between an aerobic selector activated sludge system and a conventional CSTR system. Metal biosorption by sludge harvested from experimental systems was determined by a series of batch experiments. Heavy metals studied in this research were zinc, cadmium and nickel. Results of experimental data revealed that metal biosorption by activated sludge was rapid; about 70% of the soluble metals in solution was removed during the first 30 min. The sorption isotherm showed that at metal equilibrium concentrations greater than 0.05 mg/l, the selector sludge had significantly higher sorption capacity than did the CSTR sludge. Metal biosorption behavior closely followed a Freudlich isotherm model for equilibrium concentrations above 0.05 mg/l. Results of the Freundlich model suggested that the adsorption capacity of sludge from the aerobic selector was significantly higher than that of the CSTR system.

Keywords: Heavy Metals, Activated Sludge, Aerobic Selector, Zoogloea Ramigera, Extracellular Polymers, Bacterial Extracellular Polymers, Culture

? Dentel, S.K., Bottero, J.Y., Khatib, K., Demougeot, H., Duguet, J.P. and Anselme, C. (1995), Sorption of tannic-acid, phenol, and 2,4,5-trichlorophenol on organoclays. Water Research, 29 (5), 1273-1280.

Full Text: 1995\Wat Res29, 1273.pdf

Abstract: Sorption of the organic pollutants phenol, 2,4,5-trichlorophenol, and tannic acid (Fluka) onto montmorillonite-based sorbents was studied. The sorbents were homoionic Na- or Ca-montmorillonite, montmorillonite completely exchanged with the cationic organic surfactant dimethyldistearylammonium chloride (or DDA-M), and DDA-M partially re-exchanged with Ca²⁺ (Ca-DDA-M). The influence of pH on sorption of phenol and trichlorophenol was also investigated. The sorption capacities for phenol, trichlorophenol, and tannic acid were significantly enhanced by surfactant treatment of the homoionic clay. Uptake onto the organoclays increased in the order phenol < tannic acid < trichlorophenol, which corresponds to the order of increasing hydrophobicity. The significant role played by hydrophobicity was also observed in pH effects which generally favored sorption when the pH was low enough to assure that the uncharged (protonated) species was predominant. In the case of trichlorophenol, sorption could be shown to be quantitatively attributable to the neutral species. The results of X-ray diffraction measurements showed increased d001 spacings when the DDA was intercalated into the interlamellar spaces, increasing the available sorbent porosity. This, and the linkage of uptake to solute hydrophobicity, indicates that uptake is by a partitioning mechanism, though non-linear isotherms may be caused by site limitations. Surprisingly, if a portion of the intercalated DDA is removed by exchange with Ca²⁺, the d001 spacing decreases but the sorption capacity of the organoclays is improved. One possible mechanism is improved elementary sheets cohesion due to calcium ions, imparting molecular sieve characteristics to the solid. The extent and possible selectivity of sorption using these organoclays suggests that they may provide an alternative to activated carbon sorbents in water treatment.

Keywords: Water Treatment, Organoclays, Sorption, Dimethyldistearylammonium, Montmorillonite, Tannic Acid, Phenol, Chlorophenols, Organic Pollutants, Adsorption, Montmorillonite, Smectites, Amines

Marani, D., Patterson, J.W. and Anderson, P.R. (1995), Alkaline precipation and aging of Cu(II) in the presence of sulfate. Water Research, 29 (5), 1317-1326.

Full Text: W\Wat Res29, 1317.pdf

Abstract: The effect of several operating parameters (reagents concentration, molar ratio, mixing protocol) on the composition and aging of the precipitates obtained by mixing cupric sulfate solutions with NaOH solutions was studied. The precipitate was characterized with chemical analysis (SO₄/Cu molar ratio), scanning electron microscopy, and X-ray diffraction. pH, free cupric ion activity, and sulfate concentration were measured in the soluble phase. Precipitation of either basic cupric sulfates or cupric hydroxide/oxide may take place depending on the sequence of reagents addition. Provided that the base/CuSO₄ molar ratio does not exceed 1.5, the slow addition of base to dilute CuSO₄ solutions produces either pure posnjakite [CuSO₄.3Cu(OH)₂.H₂O] or posnjakite and brochantite [CuSO₄.3Cu(OH)₂] mixtures. Upon aging, posnjakite converts to the more stable brochantite, in agreement with previous works indicating posnjakite as a kinetic precursor of brochantite. The addition of excess base to the basic salt induces its slow conversion to tenorite (CuO), changing the morphology of the precipitate from platelet-like basic salt particles to feathery bundles of tenorite needles. Aged precipitate suspensions contain brochantite or tenorite, the predicted stable solids at lower and higher pH, respectively. However, the actual predominance region of brochantite seems to extend itself, by at least one pH unit, over the tenorite predominance region predicted by the geochemical model MINTEQA2. This discrepancy has been attributed to the small dimensions, and consequent higher solubility, of tenorite crystals. Potentiometric measurements on aged tenorite suspensions support this hypothesis, indicating a solubility product of about one order of magnitude higher than expected. The results of this work can help to understand and control the formation and conversion of basic cupric sulfates, that are of great importance in such fields as removal and recovery of copper from industrial wastewaters and sludges, and patina formation in copper corrosion.

Keywords: Precipitation Copper, Brochantite, Posnjakite, Tenorite, Geochemical Modeling, Copper, Patina

Ho, Y.S., Wase, D.A.J. and Forster, C.F. (1995), Batch nickel removal from aqueous solution by sphagnum moss peat. Water Research,