Personal Research Database

Full Text: W\Wat Air Soi Pol113, 217.pdf

Abstract: Bacteriological and physico-chemical parameters of 265 samples from 39 brands sold in 5-gallon plastic and glass bottles and 2-5 L plastic containers were analyzed to determine the quality of bottled water distributed in Mexico City. Tests included fecal and total coliform counts, alkalinity, total hardness, chloride, calcium and magnesium concentrations, pH and conductivity. Correlation and cluster analyses and ANOVA were carried out, and a comparison made of the averages with the maximum permissible levels established in the Official Mexican Norms. Concerning the investigated parameters no differences (p > 0.05) between the brands were found. Physico-chemical parameters were studied and all the samples were within the permissible limits. Most samples taken from the 5-gallon containers exceeded the maximum bacteriological limits. It was concluded that the bacteriological quality of the brands studied was extremely variable. Appropriate sanitary measures, should be established to control this aspect.

Keywords: Bottled Water, Bacteriological Quality and Physico-Chemical Quality, Microbiological Quality, Canada, Sold

Namasivayam, C. and Yamuna, R.T. (1999), Studies on chromium(III) removal from aqueous solution by adsorption onto biogas residual slurry and its application to tannery wastewater treatment. Water Air and Soil Pollution, 113 (1-4), 371-384.

Full Text: W\Wat Air Soi Pol113, 371.pdf

Abstract: Adsorption studies of Cr(III) on biogas residual slurry (BRS) were caried out under varying conditions of shaking time (5-180 min), metal ion concentration (10-40 mg L^-1), adsorbent concentration (1.0 to 8.0 g L^-1) and initial pH (1.5-5.0). Adsorption follows Langmuir isotherm, being endothermic in nature. For a Cr(III) concentration of 10 mg L^-1, a maximum removal of 85% by 4 g L^-1 of adsorbent was obtained at an initial pH greater than or equal to 3.0. Desorption of Cr(III) from the spent adsorbent has also been investigated. Removal of Cr(III) from tannery wastewater by BRS was testified.

Keywords: Adsorbent, Adsorption, Adsorption Isotherms, Adsorption Kinetics, Bark, Biogas Residual Slurry, Chromium, Color, Cr(III) Adsorption, Desorption, Langmuir, Metal, Moss, Peat, pH, pH Effect, Removal, Wastewater Treatment, Water

Qafoku, N.P., Kukier, U., Sumner, M.E., Miller, W.P. and Radcliffe, D.E. (1999), Arsenate displacement from fly ash in amended soils. Water Air and Soil Pollution, 114 (1-2), 185-198.

Full Text: W\Wat Air Soi Pol114, 185.pdf

Abstract: Arsenic (As) is the biggest environment contaminant in most of the soils where fly ash is applied. Usually, it is not mobile and strongly adsorbed on to soil particles. However, in gypsum and phosphorus amended soils As may be much more mobile. A study in repacked columns was conducted to determine whether or not As becomes mobile when Ca (H₂PO₄)₂ and CaSO₄ are used as leaching solutions, and to compare the competitive interactions between PO₄-AsO₄ and SO₄^-AsO₄. Arsenic concentration in leachate was found to be approximately ten times greater when Ca (H₂PO₄)₂ was used to leach the columns as compared to CaSO₄ A maximum concentration of 800 µg As L^-1 was found in the leachate in this case, which is much higher than the groundwater limit of 50 µg L^-1 for drinking water established by the United States Environmental Protection Agency. In fly ash, the portion of arsenate non-specifically adsorbed is believed to be much lower than that of specifically adsorbed. Sulfate anions were able to displace only non-specifically adsorbed arsenate. In this case the concentration of As in leachate was found to be within acceptable limits. On the other hand, phosphate can compete with arsenate for all available adsorption sites, non-specific and specific. Phosphate displacement of both forms of arsenates increases As mobility in both control and fly ash treatments.

Keywords: Oxide Minerals, Adsorption, Ecosystems, Transport, Phosphate, Residues, Arsenate Mobility, PO₄-AsO₄ and SO₄-AsO₄ Interactions, Fly Ash, Re-Packed Columns

Al-Asheh, S. and Duvnjak, Z. (1999), Sorption of heavy metals by canola meal. Water Air and Soil Pollution, 114 (3-4), 251-276.

Full Text: Wat Air Soi Pol114, 251

Abstract: The results from this research indicate that canola meal (CM) can be used for adsorption of Zn²⁺, Cd²⁺, Cu²⁺, Pb²⁺ and Ni²⁺ from aqueous solutions. The order of sorption for these metals in single metal systems was as follows (molar basis): Zn²⁺ > Cu²⁺ > Cd²⁺ > Ni²⁺ > Pb²⁺. It was noted that a decrease in the concentration of CM caused a higher metal loading on the meal. Increases in the metal concentration, temperature or pH resulted in increased sorption of the metals by the meal. The systems with identical ratios of CM to Zn²⁺ concentrations, regardless of their levels, resulted in the same amount of metal adsorbed per unit weight of meal. The Freundlich isotherm type model was used in this study and was found to fit the experimental equilibrium concentration data of Zn²⁺ and Cd²⁺; however, the Langmuir isotherm model fit only the equilibrium data of Zn²⁺. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX) microanalyses revealed that the metal ions were sorbed mainly at the cell wall and only small amounts of ions diffused into the cytoplasm of the CM cells. The Electron Spin Resonance (ESR) tests were inconclusive regarding the direct participation of free radicals in copper sorption.

Keywords: Accumulation, Adsorbents, Adsorption, Biosorption, Canola, Canola Meal, Cd²⁺, Cell Wall, Cells, Concentration, Concentrations, Copper, Cu²⁺, EDX, Energy Dispersive X-Ray, Equilibrium, Esr, Free Radicals, Freundlich, Freundlich Isotherm, Heavy Metals, Ions, Isotherm, Langmuir, Langmuir Isotherm, Levels, Loading, Mechanism, Metal, Metal Ions, Metals, Model, Participation, Pb²⁺, pH, Radicals, Removal, Research, Rhizopus-Arrhizus, Scanning Electron Microscopy, SEM, Sorbed, Sorption, Temperature, Tests, Vulgaris, Waste-Water, Zn²⁺

McKay, G., Porter, J.F. and Prasad, G.R. (1999), The removal of dye colours from aqueous solutions by adsorption on low-cost materials. Water Air and Soil Pollution, 114 (3-4), 423-438.

Full Text: W\Wat Air Soi Pol114, 423.pdf

Abstract: The ability of five low cost adsorbents-rice husk, cotton, bark, hair and coal-to adsorb two basic dyes, namely, Safranine and Methylene Blue, has been studied. Equilibrium isotherms have been determined and analysed using the Langmuir equations. The monolayer saturation capacities for Safranine are 1119, 838, 875, 190 and 120 mgg^-1 adsorbent and for Methylene Blue are 914, 312, 277, 158 and 250 mgg^-1 adsorbent for bark, rice husk, cotton waste, hair and coal respectively. A limited number of fixed bed column studies have been performed and the bed depth service time for each dye-adsorbent system has been determined.

Keywords: Acid Dye, Adsorbent, Adsorbents, Adsorption, Bark, Coal, Dye, Dye Sorption, Dyes, Equilibrium, Equilibrium Isotherms, Fixed Bed, Fly-Ash, Langmuir, Low-Cost Sorbents, Natural Adsorbents, Removal, Waste

Wasay, S.A., Barrington, S. and Tokunaga, S. (1999), Efficiency of GAC for treatment of leachate from soil washing process. Water Air and Soil Pollution, 116 (3-4), 449-460.

Full Text: W\Wat Air Soi Pol116, 449.pdf

Abstract: Granular activated carbon (GAC), granular activated alumina (GAA) and a ferric chloride solution (FCS) were tested for the treatment of leachate contaminated by heavy metals. The leachate was collected following the remedation of soils using weak organic acids and/or their salts, EDTA and DTPA. Only GAC was found to effectively remove heavy metals (Cd, Cu, Cr, Hg, Mn, Pb and Zn as chelates) from the leachate. At optimum pH ranging from 5.4 to 6.9, 97% of Hg was removed while at optimum pH ranging from 6.9 to 7.7, 78 to 96% of Cd, Cu, Mn, Pb and Zn were removed. Some 77% of the Cr was removed at optimum pH of 5.4. Adsorption rate constant and Langmuir adsorption capacity of GAC were found to be 0.01 min^-1 and 19 mg metal chelate g^-1 of GAC, respectively. Freundlich constants, k and n were found to be 21 mg g^-1 and 2.778, respectively. The brown color of the leachate turned colorless after GAC treatment.

Keywords: GAC, Heavy Metal, Leachate, Soil Washing, Treatment, Adsorption Characteristics, Heavy-Metals, Chelating-Agents, Organic-Acids, Remediation, Complexes

Lo, I.M.C. and Alok, P.A. (2000), Computerized methodology for evaluating drinking water treatment technologies: Part I. Water Air and Soil Pollution, 117 (1-4), 61-81.

Full Text: W\Wat Air Soi Pol117, 61.pdf

Abstract: A computer based system, Best Available Technology Evaluator (BATE), has been developed for the evaluating cost and performance of the best available technologies for removing volatile organic chemicals (VOCs) from drinking water. The treatment processes considered are air stripping tower (AST), and air stripping with off-gas control by gas phase granular activated carbon (GPGAC) and liquid phase granular activated carbon (LPGAC). BATE is unique in its ability to model multicomponents, optimise total cost for different process configurations and yield the best process design for a given VOC scenario. This paper, the first in a two-part series, highlights a new cost optimization method for the AST with GPGAC system and a technique for combining mathematical models for efficient process design of AST and GPGAC processes. Discussion of LPGAC simulation results and comparison of an LPGAC system with AST and GPGAC processes for a variety of VOC scenarios will follow in the next paper.

Keywords: Design, Adsorption, Adsorbers, Vocs, GAC, Air Stripping, Gas Phase Activated Carbon Adsorption, Multicomponent, Off-Gas Control, Optimization

Lo, I.M.C. and Alok, P.A. (2000), Computerized methodology for evaluating drinking water treatment technologies: Part II. Water Air and Soil Pollution, 117 (1-4), 83-103.

Full Text: W\Wat Air Soi Pol117, 83.pdf

Abstract: The previously described computer based system, Best Available Technology Evaluator (BATE), is used for least cost comparison of AST and AST with GPGAC and LPGAC processes. The underlying LPGAC cost and process dynamics simulation models are complex and need to be modified and coupled in an efficient manner in order to yield useful preliminary design data. This paper discusses a technique for such model combination and a method for finding the LPGAC least cost. Sensitivity analysis of LPGAC cost and performance with respect to common operating parameters such as empty bed contact time (EBCT), hydraulic loading rate (HL), and process configuration is discussed in light of this efficient model combination and least cost finding technique. This study shows that there is an optimal combination of EBCT and LPGAC process configuration for which its cost is comparable to that of AST alone and AST with GPGAC. Such optimal combinations are discussed for some VOC scenarios.

Keywords: Adsorption, Adsorber, Removal, Design, GAC, Adsorber Configuration, Least Cost, Multicomponent, Liquid Phase Granular Activated Carbon Adsorption, Multicomponent

Khaodhiar, S., Azizian, M.F., Osathaphan, K. and Nelson, P.O. (2000), Copper, chromium, and arsenic adsorption and equilibrium modeling in an iron-oxide-coated sand, background electrolyte system. Water Air and Soil Pollution, 119 (1-4), 105-120.

Full Text: W\Wat Air Soi Pol119, 105.pdf

Abstract: The adsorption of copper, chromate, and arsenate (CCA) onto iron-oxide-coated sand (IOCS) was examined in single-metal and mixed-metalsystems. Copper and arsenate were strongly adsorbed or formed inner-sphere surface complexes with the IOCS surface while chromate was weakly adsorbed or formed an outer-sphere surface complex with the IOCS surface. Copper adsorption by IOCS slightly increased in the presence of arsenate but was not affected by the presence of chromate. Arsenate adsorption was not affected by the presence of copper and/or chromate. Chromate adsorption increased in the presence of copper by the combination of electrostatic effects and possible surface-copper-chromate ternary complex formation. The presence of arsenate significantly decreased chromate adsorption due to competition for adsorption sites and electrostatic effects. Using inner-sphere surface complexation constants for copper and arsenate and outer-sphere surface complexation constants for chromate, the triple-layer model (TLM) was successful in describing adsorption of copper, chromate, and arsenate in single-solute systems. The model indicated that each metal uses a different number of adsorption sites. For CCA metals-IOCS systems, the equilibrium constants determined from single-solute systems were not able to predict adsorption from multi-solute systems. The TLM does not currently account for the heterogeneity of oxide surface sites and the formation of ternary complexes and/or solid phases that do not exist in single-solute systems.

Keywords: Competitive Adsorption, Oxyhydroxide, Goethite, Hydroxide, Chromate, Complexation, Manganese, Interface, Aluminum, Metals, Adsorption, Arsenic, Chromium, Copper, Iron-Oxide-Coated Sand, Modeling

Doğan, M., Alkan, M. and Onganer, Y. (2000), Adsorption of Methylene blue from aqueous solution onto perlite. Water Air and Soil Pollution, 120 (3-4), 229-248.

Full Text: W\Wat Air Soi Pol120, 229.pdf

Abstract: Adsorption of Methylene blue from aqueous solutions onto unexpanded and expanded perlite samples activated by H₂SO₄ and NaCl solutions has been investigated, to assess the possibility of using perlite for removing cationic dyes from aqueous solutions. The effects of pH and temperature of dye solution on the adsorption capacities have been evaluated. The experimental data were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (Q_m and K) have been calculated. The removal efficiency (P) and dimensionless separation factor (R) have shown that perlite can be used for removal of Methylene blue from aqueous solutions, but unexpanded perlite is more effective.

Keywords: Adsorption Isotherms, Dye, Methylene Blue, Perlite, Basic-Dyes, Fly-Ash, Equilibrium, Removal

Khattri, S.D. and Singh, M.K. (2000), Colour removal from synthetic dye wastewater using a bioadsorbent. Water Air and Soil Pollution, 120 (3-4), 283-294.

Full Text: W\Wat Air Soi Pol120, 283.pdf

Abstract: Removal of dyes (Crystal Violet, Methylene Blue, Malachite Green and Rhodamine B) from aqueous solutions at different concentrations, pH and temperatures by Neem sawdust has been carried out successfully. The percentage of the dye adsorbed by Neem sawdust decreased from 91.56 to 78.94 and 84.93 to 71.25 for Crystal Violet and Malachite Green, respectively, when the concentration of the dye was increased from 6 to 12 mgL^-1 at a temperature 30±1C and pH 7.2. Adsorption of other dyes (Methylene Blue and Rhodamine B) also decreased with increasing concentration of the dye in solutions. The values of the rate constant of adsorption (k_ad) of Crystal Violet at 25, 35 and 45C were found to be 10.80, 10.52 and 10.2510^-2 min^-1, respectively. The values of the Langmuir constant for adsorption capacity (Q_o) of Crystal Violet on the adsorbent varied from 4.44 to 3.99 mgg^-1, respectively, with the increase of temperature between 25 to 45C. The equilibrium data followed the Langmuir model of adsorption. The variation in the extent of removal with pH has been explained on the basis of surface ionisation and complexation. Thermodynamic parameters (G, H and S) have also been determined to explain the results.

Keywords: Aqueous-Solutions, Chrome Dye, Fly-Ash, Adsorbents, Adsorption, Cost, Adsorption, Dye Removal, Wastewater Treatment

Ho, Y.S. and McKay, G. (2000), Batch sorber design using equilibrium and contact time data for the removal of lead. Water Air and Soil Pollution, 124 (1-2), 141-153.

Full Text: W\Wat Air Soi Pol124, 141.pdf

Abstract: The two-stage batch sorption design of the sorption of lead ions onto peat has been studied based on a Langmuir isotherm type equation obtained from different contact time studies. A model has been developed to predict the optimised minimum operating time to determine a specified amount of lead removal. The sorption capacity at any contact time has been evaluated with an equation also based on the mathematical form of the Langmuir equation.

Keywords: Batch Sorption, Contact Time Optimisation, Langmuir Equation, Lead Ions, Two-Stage, Aqueous-Solutions, Fly-Ash, Hexavalent Chromium, Waste-Water, Adsorption, Peat, Sorption, Cadmium, Ions, Kinetics

Ku, Y. and Chiou, H.M. (2002), The adsorption of fluoride ion from aqueous solution by activated alumina. Water Air and Soil Pollution, 133 (1-4), 349-360.

Full Text: W\Wat Air Soi Pol133, 349.pdf

Abstract: The adsorption of fluoride ion in aqueous solution by using alumina was studied in this research. The experimental results indicated that the removal efficiency was influenced significantly by solution pH and the optimum operating pH was found to be in the range of 5 to 7. For neutral and acidic solutions, the adsorption capacities of fluoride by alumina was interfered by the presence of sulfate. The Langmuir and Freundlich isotherms can well describe the equilibrium behaviors of the adsorption processes. The experimentally determined low values of activation energy indicate nonspecific adsorption is the predominant mechanism. The surface reaction-limiting batch kinetic model can adequately describe the removal behaviors of fluoride ion by alumina adsorption in the batch system.

Keywords: Adsorption, Alumina, Fluoride, Removal, Water

López, A., Lázaro, N., Morales, S. and Marqués, A.M. (2002), Nickel biosorption by free and immobilized cells of Pseudomonas fluorescens 4F39: A comparative study. Water Air and Soil Pollution, 135 (1-4), 157-172.

Full Text: W\Wat Air Soi Pol135, 157.pdf

Abstract: The biosorption of nickel ions on Pseudomonas fluorescens 4F39 free cells or immobilized cells in beads of agar (biobeads) has been studied in batch experiments to determine the effect of cell immobilization on the metal accumulation properties of both systems. Bacterial cells were immobilized in agar beads following the interphase technique. When free cells were used, the sorption equilibrium was reached in 5 min but with biobeads it took 24 hr as a consequence of metal diffusion. The pH of the Ni²⁺ solution was found to be critical for Ni²⁺ accumulation, the optimum being 8, although the magnitude of this effect was lower in immobilized cells. The equilibrium data have been analysed using the Langmuir adsorption model. The q_max of free cells, immobilized cells and biobeads was 145, 37 and 7.6 mg Ni²⁺/g dry sorbent, respectively. The removal capacity of free cells and immobilized cells increased when the cell concentration decreased. The maximum removal efficiency of biobeads was obtained when the cell concentration was 1.43 mg dry cells/mL Ni²⁺ solution. The agar concentration in biobeads affected the Ni²⁺ accumulation, the optimum being 2%. Desorption of Ni²⁺ with 0.5 mM dipicolinic acid was efficient. Cycles of accumulation/desorption resulted in a loss of non immobilized cells. An increase of the removal efficiency from the first cycle of accumulation/desorption was observed with biobeads.

Keywords: Biobeads, Desorption, Free Cells, Immobilized Cells, Langmuir Isotherm, Ni²⁺ Heavy-Metals, Marine-Algae, Toxic Metals, Removal, Biomass, Accumulation, Cadmium, Bacteria, Cobalt

Bayat, B. (2002), Combined removal of zinc(II) and cadmium(II) from aqueous solutions by adsorption onto high-calcium Turkish fly ash. Water Air and Soil Pollution, 136 (1-4), 69-92.

Full Text: W\Wat Air Soi Pol136, 69.pdf

Abstract: The aim of this work is the investigation of possible use of fly ash in the removal of zinc (Zn²⁺) and cadmium (Cd²⁺) contained in aqueous solutions. Batch adsorption experiments were performed in order to evaluate the removal efficiency of lignite-based fly ash. The parameters studied include contact time, pH, temperature, initial concentration of the adsorbate and fly ash dosage. The contact time necessary to attain equilibrium was found to be two hours. Maximum adsorption occurred in the pH range of 7.0 to 7.5. The percent adsorption of Zn²⁺ and Cd²⁺ increased with an increase in concentration of Zn²⁺ and Cd²⁺, dosage of fly ash and temperature. The applicability of Langmuir isotherm suggests the formation of monolayer coverage Zn²⁺ and Cd²⁺ ions at the outer surface of the adsorbent. Thermodynamic parameters suggested the endothermic nature of the adsorption process. The fly ash was found to be an metal adsorbent as effective as activated carbon.

Keywords: Adsorption, Cadmium, Fly Ash, Freundlich, Langmuir, Zinc, Low-Cost Adsorbents, Waste-Water, Activated Carbon, Natural Adsorbents, Acid Dye, Effluents, Cu(II), Cr(VI)

Singh, K.S. and Viraraghavan, T. (2002), Effect of temperature on bio-kinetic coefficients in UASB treatment of municipal wastewater. Water Air and Soil Pollution, 136 (1-4), 243-254.

Full Text: W\Wat Air Soi Pol136, 243.pdf

Abstract: Upflow anaerobic sludge blanket (UASB) reactors were used to treat municipal wastewater at temperatures of 6, 11, 15, 20 and 32 degreesC and at hydraulic retention times (HRTs) ranging from 48 to 3 h over an operational period of approximately 860 days. The Monod model was used to evaluate substrate utilization. The Arrhenius model was used to calculate the activation energies from which temperature coefficients were determined. It was found that the maximum specific substrate utilization rate constant (k) decreased from 0.387 d^-1 (at 32 degreesC) to 0.041 d^-1 (at 6 degreesC). The decay rate constant (k(d)), yield coefficient (Y-g), half velocity constant (K-s) and maximum specific growth rate (mu(m)) were also impacted by temperature in the UASB treatment of municipal wastewater.

Keywords: UASB Treatment, Municipal Wastewater, Bio-Kinetic Parameters, Temperature, Anaerobic Treatment, Water Treatment, Reactors, Sewage

Jain, C.K. and Sharma, M.K. (2002), Adsorption of cadmium on bed sediments of river Hindon: Adsorption models and kinetics. Water Air and Soil Pollution, 137 (1-4), 1-19.

Full Text: W\Wat Air Soi Pol137, 1.pdf

Abstract: The adsorption characteristics of cadmium on bed sediments of river Hindon in western Uttar Pradesh (India) have been studied. The effect of various operating variables, viz., initial concentration, solution pH, sediment dose, contact time, particle size and temperature has been studied. The optimum equilibration time was found to be 60 min, which was independent of initial concentration of cadmium ions. The adsorption curves were smooth and continuous leading to saturation, suggesting the possible monolayer coverage of cadmium ions on the surface of the adsorbent. The adsorption of cadmium increased with an increase in pH. Furthermore the adsorption of cadmium increased with increasing adsorbent concentration and decreased with adsorbent particle size. The important geochemical phases, iron and manganese oxide, support the adsorption of cadmium ions. The adsorption data were analysed using the Langmuir and Freundlich adsorption models to determine the mechanistic parameters related to the adsorption process. Thermodynamic parameters, viz., free energy change, enthalpy change and entropy change, were also determined. The negative values of free energy change (DeltaGdegrees) indicated the spontaneous nature of the adsorption and positive values of enthalpy change (DeltaGdegrees) suggested the endothermic nature of the adsorption process. The intraparticle diffusion of cadmium through pores in the adsorbent was found be the main rate-limiting step

Keywords: Adsorbent, Adsorption, Bed Sediments, Cadmium, Chromium, Clay, Heavy-Metals, Intraparticle Diffusion, Ions, Kinetics, Lead, Removal, Sawdust, Soil, Solids, Sorption, Waste-Water, Water

Chang, T.W., Wang, M.K. and Lin, C. (2002), Adsorption of copper in the different sorbent/water ratios of soil systems. Water Air and Soil Pollution,