Personal Research Database

Full Text: 2000\J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 379

Abstract: The ability of powdered activated carbon to adsorb phenol and chromium(VI) ions, both singly and in combination, was investigated in a batch system. The effects of initial pH and single-and dual-component concentrations on the equilibrium uptakes were investigated. The optimum initial adsorption pH for both chromium(VI) ions and phenol was determined as 1.0. Multi-component adsorption studies were performed at this initial pH value. It was observed that the equilibrium uptakes of phenol and chromium(VI) ions were changed due to the presence of other component. Adsorption isotherms were developed for both single-and dual-component systems at pH 1.0, and expressed by the mono-and multi-component Langmuir, Freundlich and Redlich-Peterson adsorption models and model parameters were estimated by the non-linear regression method in the studied concentration ranges. The non-competitive Freundlich model were well fitted to the mono-component adsorption equilibrium data for both phenol and chromium(VI) ions while the competitive, modified Freundlich model showed good prediction in the competitive adsorption of phenol and chromium(VI) ions on the adsorbent. The results suggested that powdered activated carbon may find promising applications for simultaneous removal and separation of phenol and chromium(VI) ions from aqueous effluents.

Keywords: Multi-Component Adsorption, Phenol, Chromium(VI), Powdered Activated Carbon, Mono-and Multi-Component Adsorption Isotherms, Isotherms, Organics

Stefanova, R.Y. (2000), Sorption of metal ions from aqueous solutions by thermally activated electroplating sludge. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 35 (4), 593-607.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 593.pdf

Abstract: The sludge waste obtained from metal plating industries has been converted into a low-cost sorbent material. The thermally treated activated electroplating sludge is characterized, as well as its use for the removal of metal ions. The effect of contact time, the pH, the sorbate concentrations, the mixture of metal ions and the temperature on the sorption of lead, copper, zinc and nickel were studied in batch experiments. Kinetic studies were undertaken in order to make clear the mechanism of the process. The sorption on electroplating sludge follows both Langmuir and Freundlich’s models. The degree of removal of metal ions was found to be dependent on the final pH of the contact solutions. The percentage of the sorbed metal ions rapidly rises at pH above 4.2-5.5. Some experiments were also carried out for chemical regeneration of the exhausted electroplating sludge. The order of preference of sorption of meal ions in a single and in a multicomponent system has been established.

Keywords: Waste Fe(III)/Cr(III) Hydroxide, Water, Solidification, Adsorption, Chromium, Removal, Zinc, Lead, Electroplating Sludge, Metal Ions, Sorption, Thermally Activated Sorbent

Khan, A.H., Rasul, S.B., Munir, A.K.M., Habibuddowla, M., Alauddin, M., Newaz, S.S. and Hussam, A. (2000), Appraisal of a simple arsenic removal method for groundwater of Bangladesh. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 35 (7), 1021-1041.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 1021.pdf

Abstract: A simple three-pitcher (locally known as ‘3-kalshi’) filtration assembly made entirely from readily available local materials is tested for its efficacy in removing arsenic from the groundwater of Bangladesh. In a 3-kalshi assembly, the first kalshi has iron chips and coarse sand, the second kalshi has wood charcoal and fine sand, and the third kalshi is the collector for filtered water. About 240 L of arsenic contaminated groundwater and groundwater spiked with high concentrations of both As(III) and As(V) were filtered. Analytical measurements were performed by using anodic stripping voltammetry (ASV) for trace level As(III) and As(total) and redox potential. Atomic absorption spectrometry with graphite furnace and Zeeman background correction (AASGF-Z) and inductively coupled plasma atomic emission spectrometry (ICPAES) were used to validate measurements of arsenic and measure 24 other metals before and after filtration. Total Fe, ionic conductivity, E-h, pH, temperature and flow rates were measured at various stages of the filtration process. It has been shown that more toxic As(III) can be removed from 800 ppb to below the detection limit of 2 ppb. The As(total) can be removed to a concentration below 10 ppb for most samples even at the highest input concentration of 1100 ppb As(total). The dissolved iron concentration decreased from an average 6000 ppb to 200 ppb. Calculations based on compound formation and arsenic adsorption on hydrous ferric oxide show that, with a constant input of dissolved iron the arsenic removal capacity increases linearly with each filtration. Although the role of metallic iron was difficult to quantitate, it provided excess soluble iron in the filtering media of the second kalshi. The wood charcoal was used to remove any organic impurities that may be present in groundwater. The redox potential change shows speciation of iron in agreement with literature data. The decrease in conductivity by 35% of the original value indicates substantial removal of dissolved ions. This is also supported by ICPAES measurement. The filtered water remained crystal clear for months and free from most toxic metal ions. The daily capacity of the 3-kalshi system varies from 42-148 L/day. The final water quality meets and exceeds the guideline values suggested by USEPA, World Health Organization and Bangladesh. We suggest the use of this simple setup to make potable water.

Keywords: Arsenic Removal, Groundwater, Bangladesh, Amorphous Iron Hydroxide, Drinking-Water, West-Bengal, Biological Samples, Affected People, 6 Districts, Adsorption, India, Speciation, Electrode

Panayotova, M. (2000), Use of zeolite for cadmium removal from wastewater. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 35 (9), 1591-1601.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 1591.pdf

Abstract: Kinetics and thermodynamics of uptake of Cd²⁺ tin concentration of 10 and 50 mg/dm³) by natural and modified zeolite have been investigated. Kinetic data obtained are best described by the kinetic equation for the second order irreversible reactions and the equilibrium data obtained best fit to Freundlich adsorption isotherm. It has been found that (a) the ratio of wastewater to zeolite equal to 0.1 dm³: 1 g was the optimum, (b) use of zeolite with particles’ size <0.09 µm increased Cd²⁺ uptake, (c) Cd²⁺ removal due to zeolite’s uptake was the highest if the pH value of water to be treated was in the range of pH 5-7, (d) uptake of Cd²⁺ was considerably decreased in presence of Ca²⁺ and Mg²⁺ in concentrations 2 folds the concentration of Cd²⁺, (e) zeolite treated with NaCl and CH₃COONa showed the highest uptake ability, (f) concentrations lower than 0.5 and 8-10 mg/dm³ can be achieved by one stage treatment of soft water when the initial Cd²⁺ concentrations are 10 and 50 mg/dm³ correspondingly, and (g) contacting with 2 mol/dm³ NaCl solution can easily regenerate loaded zeolite.

Keywords: Cadmium Ions, Removal, Wastewater, Zeolite

Panayotova, M. (2000), An assessment of lead pollution caused by vehicles emissions in a highly inhabited region of Sofia, Bulgaria. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 35 (9), 1693-1700.

Full Text: J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 1693

Abstract: Lead concentrations have been determined in air, soil and vegetation samples taken along a major boulevard in Sofia town. Concentrations of total suspended particles (tsp) were also measured. The following concentrations have been found: tsp - 0.168 divided by 1.242 mg/m³; Pb aerosols - 0.00058 divided by 0.00573 mg/m³; Pb in soil - 16.2 divided by 184.3 mg/kg; Pb in grass - 2.6 divided by 27.4 mg/kg. Tsp concentrations as well as Pb concentrations in air, soil and vegetation correlated negatively with distance to the road. Airborne particle Pb is the main source for soil and vegetation pollution. Sequential extraction showed that Pb was bound predominately to CO₃^2- and only in a small quantity to easily exchangeable phase, to iron and manganese oxides and to organic matter. The results showed that Pb concentrations in soil meet the maximum permissible concentrations, except for the 5-10 meters adjacent to the road. However, a possibility exists for Pb accumulation in soil. Planting suitable vegetation and promoting use of unleaded fuel can be proposed as measures to be taken.

Keywords: Urban Traffic, Lead Pollution, Air, Soil, Vegetation, Soil

? (2000), Appraisal of a simple arsenic removal method for groundwater of Bangladesh (vol A35, pg 1021, 2000). Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 35 (10), 1995-1996.

Full Text: 2000\J Env Sci Hea Par A-Tox Haz Sub Env Eng35, 1995

Stefanova, R.Y. (2001), Metal removal by thermally activated clay marl. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (3), 293-306.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 293.pdf

Abstract: A sorption active product has been obtained from Bulgarian clay marl by thermal activation at 750 degreesC. The modified aluminosilicate material is characterized, as well as its use for the removal of metal ions. The effect of the initial metal ion concentration, the contact time, pH, the solution temperature and the ionic strength on the uptake of lead, copper and zinc ions from aqueous solutions were studied in batch experiments. The kinetics of removal of metal ions on modified clay marl appears dependent on the sorbate/sorbent ratio. At low cation concentrations sorption follows a Langmuir isotherm, while at higher sorbate/sorbent ratios the sorption isotherms of metal ions are described by Freundlich’s equation. Ar the pH region of the sorption edge the removal of metal ions by surface complexation and surface precipitation mechanisms is indistinguishable. It is observed that the influence of temperature on the uptake ability of the clay marl is most considerable up to 40 degreesC. These studies show that the thermally modified clay marl can be successfully used for removal of metal ions from water solutions in a wide range of concentrations.

Keywords: Clay Marl, Metal Ions, Removal, Sorption, Thermal Modification, Equilibrium, Kaolinite, Sorption, Cadmium

Aksu, Z. and Dönmez, G. (2001), Comparison of copper(II) biosorptive properties of live and treated Candida sp. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (3), 367-381.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 367.pdf

Abstract: Biosorption of copper(II) ions from aqueous solutions was studied to compare the binding capacities of untreated (live) or treated (dried, autoclaved, perchloric acid (HClO₄)-washed, ethanol-treated, formaldehyde-treated) Candida sp. Due to the ion exchange nature of metal biosorption, copper(II) uptake was strongly affected by the solution pH and optimum adsorption pH value was determined as 5.0 for all the live and treated Candida sp. At the optimal conditions, metal ion uptake increased with increasing initial copper(II) concentration up to 300 mg l^-1 for all the biomass types. It is found that all the treatment methods used to kill the yeast (except for formaldehyde treatment) increased the copper(II) biosorption capacity of Candida cells. The results also indicated that copper(II) biosorption by live, autoclaved and formaldehyde-treated yeasts was consisted of an initial, rapid surface binding of copper(II) followed by a second, slower intracellular uptake of copper(II), but copper(II) uptake by the other treated yeasts took place only via surface binding. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of copper(II) by all the untreated and treated Candida.

Keywords: Biosorption, Copper(II), Candida sp, Saccharomyces-Cerevisiae, Metal-Cations, Biomass, Ions, Bioaccumulation, Removal

Parkpoin, P., Thongra-ar, W., DeLuane, R.D. and Jugsujinda, A. (2001), Adsorption and desorption of mercury by Bangpakong River sediments as influenced by salinities. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (5), 623-640.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 623.pdf

Abstract: Mercury adsorption and desorption by Bangpakong River sediments (pH range 6.8-7.8) of Thailand were investigated at salinity levels of 0, 5, 15 and 30 parts per thousand using a batch equilibration techniques. Using Freundlich isotherm adsorption and desorption data collected represented a nonlinear form. A significant portion (90-99%) of added Hg (2-10 mg L^-1) was sorbed by the sediment. Mercury adsorption isotherms or percentage adsorbed were similar among the four salinities tested. In the absence of salinity, Hg adsorption was highly influenced by pH. Whereas in the presence of salinity gradients, Hg(II)-organic complexes predominated over Hg(II)-Cl complexes, neutralizing effect of chloride concentrations and pH on the adsorption phenomena. Organic matter and clay contents of sediment were responsible for the Hg adsorption. Fe and Mn oxides showed negative correlation with the Hg adsorption capacity (r = -0.549 and -0.594 respectively), Increase in Hg desorbed from the sediments occurred only at the 30 parts per thousand salinity level. The Hg adsorption-desorption characteristics of the sediments studied exhibited a very strong irreversible sorption of added inorganic Hg. River sediment such as sediment as shown in this study with significant levels of organic matter and clay have the potential to retain Hg making it less bioavailable and mobile thus reducing potential toxicity to aquatic organisms in the environment.

Keywords: Adsorption, Desorption, Freundlich Isotherm, Mercury, River Sediment, Salinity, Salt Water Intrusion, Chloride Concentration, Humic Substances, Organic-Matter, Sorption, Soil, pH, Goethite, Kinetics, Cadmium, Hg(II)

? Liu, C.H. and Lo, K.V. (2001), Ammonia removal from compost leachate using zeolite. II. A study using continuous flow packed columns. Journal of Environmental Science and Health Part B-Pesticides Food Contaminants and Agricultural Wastes, 36 (5), 667-675.

Full Text: 2001\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 667.pdf

Abstract: Bench-scale packed zeolite columns were set up and operated to investigate the continuous removal of ammonium ions from compost leachate. The effects of hydraulic retention time (HRT), and particle size of the zeolite on the ammonia adsorption capacity were studied. For both the coarse particle and the powdered zeolite columns, higher ammonia removal efficiencies were achieved with longer HRT (i.e., lower influent flow rate) tests. At the same HRT, ammonia removal efficiencies from tests with powdered zeolite were generally 20% higher than tests with the coarse particle zeolite. A HRT of 6 hours was found appropriate for efficient ammonia removal, and an operating capacity of 1.31 mg N/g zeolite was obtained. Over 98% of the ammonia input from the influent was consistently removed for over 5 bed volumes (BV) of compost leachate flowing through the zeolite column. Zeolite proved to have a great potential as a medium for ammonia removal in treating composting leachate.

Keywords: Adsorption, Ammonia Removal, Capacity, Column Study, Compost, Compost Leachate, Composting Leachate, Removal, Retention, Size, Zeolite

Annadurai, G., Juang, R.S. and Lee, D.J. (2001), Adsorption of Rhodamine 6G from aqueous solutions on activated carbon. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (5), 715-725.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 715.pdf

Abstract: The effects of particle size (0.5 similar to 1.0 mm), temperature (30 similar to 60 degreesC), and solution pH (7 similar to 9) on the adsorption equilibrium of dye Rhodamine 6G by activated carbon were studied in batch modes. The isotherm data could be well described by the Langmuir equation. Under the ranges tested, a maximum adsorption capacity of 44.7 mg/g was obtained. Batch kinetic parameters such as the Lagergren’s rate constant and intraparticle diffusion coefficient of adsorption were determined. It has been shown that the intraparticle diffusion of dye molecules within the adsorbents was identified as the rate-limiting step in the present adsorption process.

Keywords: Adsorption, Equilibrium, Kinetics, Rhodamine 6 G, Activated Carbon, Waste-Water, Fly-Ash, Removal, Adsorbents, Dye, Equilibrium, Sorption, Chitin, Earth

? Haron, M.J. and Yunus, W.M.Z.W. (2001), Removal of fluoride ion from aqueous solution by a cerium-poly(hydroxamic acid) resin complex. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (5), 727-734.

Full Text: 2001\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 727.pdf

Abstract: A cerium-loaded poly(hydroxamic acid) chelating ion exchanger was used for fluoride ion removal from aqueous solution. The resin was effective in decreasing the fluoride concentration from 5 mM down to 0.001 mM in acidic pH between 3 and 6. The sorption followed a Langmuir model with a maximum capacity of 0.5 mmol/g. The removal is accomplished by an anion exchange mechanism. The rate constant for the sorption was found to be 9.610^-2 min^-1. A column test shows that the fluoride ion was retained on the column until breakthrough point and the fluoride sorbed in the column can be eluted with 0.1 M NaOH. The column can be reused after being condition with hydrochloric acid at pH 4. The resin was tested and found to be effective for removal of fluoride from actual industrial wastewater.

Keywords: Acid, Breakthrough, Cerium-Poly(Hydroxamic Acid) Resin, Fluoride, Fluoride Removal, Industrial Wastewater, Ion Exchange, pH, Removal, Resin, Sorption

El-Bishtawi, R.F. and Ali, A.A.H. (2001), Sorption kinetics of lead ions by zeolite tuff. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (6), 1055-1072.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 1055.pdf

Abstract: The kinetics of sorption of Pb ions by zeolite tuff treated with NaCl solution was studied using agitated batch laboratory apparatus. The uptake of ions was determined as a function of time at different values of initial Pb ion concentration, zeolite particle size, slurry concentration, solution temperature and pH. The pseudo-second order reaction model was successfully applied to the experimental data with correlation coefficients higher than 0.98. Sorption rates decreased with increase in average particle diameter while it increased with increase in each of the initial Pb ion concentration, slurry concentration, solution temperature and solution pH. Results indicate the importance of chemisorption.

Keywords: Heavy Metals, Lead, Zeolite, Kinetics, Ion Exchange, Sorption, Heavy-Metals

Yang, W.P., O’Flaherty, B. and Cholli, A.L. (2001), Fast analysis of water samples for detection of anions by capillary zone electrophoresis. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (7), 1271-1285.

Full Text: J\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 1271.pdf

Abstract: A capillary zone electrophoresis (CZE) method with relatively low separation voltage and short capillary length, using indirect UV detection was developed for the fast and quantitative determination of Cl^-, NO₂^-, SO₄^2-, NO₃^- F^- and HCO^- in potable water samples. Baseline separation of inorganic and organic anions was achieved within I min. The optimal carrier electrolyte consisted of 6.0 mM sodium chromate, 2.5 mM CTAB and 3.5% acetonitrile at pH 9.0. The effects of pH and the concentrations of electrolyte and flow modifiers on the resolution were investigated. Two injection methods, gravity and electrokinetic, were compared. The application of electrokinetic injection, using pyroglutamic acid as an internal standard was found to provide a method that is fast, sensitive and quantitative, with an R.S.D. for migration times from 0.1% to 0.3% and for peak areas from 1.8% to 4.1%. The limits of detection were 0.08 mg/L Cl^-, 0.3 mg/L NO₂^-, 0.1 mg/L SO₄^2-, 0.1 mg/L NO₃^-, 0.07 mg/L F^-, and 0.3 mg/L HCO₃^-. This method has been successfully applied to determine SO₄^2- Cl^-, NO₂^- SO₄^2-, NO₃^- F^-, HCO₃^- in municipal water, surface water and bottled water samples.

Keywords: Capillary Zone Electrophoresis, Water Analysis, Electrokinetic Injection, Anions, Chloride, Nitrite, Fluoride, Sulfate, Bicarbonate, Ion Electrophoresis, Inorganic Anions, Carboxylic-Acids, Organic-Acids, Separation, Optimization, System, Chromatography, Selectivity, Injection

? Liu, C.H. and Lo, K.V. (2001), Ammonia removal from composting leachate using zeolite. I. Characterization of the zeolite. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (9), 1671-1688.

Full Text: 2001\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 1671.pdf

Abstract: The effects of ammonium concentrations, contact time, and zeolite particle sizes on the ammonium adsorption capacities of a Canadian zeolite were studied using batch experiments. Both the rates and capacities of ammonium adsorption increased with increased concentrations of ammonium in solution. Ammonium adsorption increased significantly with decreasing zeolite particle size for all tests and the adsorption capacities ranged from 14.35-17.81 mg N/g. Also, ammonia adsorption increased with contact time, and it occurred rapidly at the beginning of contact, and then gradually decreased as time progressed. Langmuir isotherm best describes the equilibrium of ammonia adsorption on zeolite. Particle diffusion was the rate-controlling mechanism for the first 4 h of contact. In spite of competition potassium ions, zeolite has shown a great potential for ammonia removal from composting leachates.

Keywords: Ammonia Removal, Composting Leachate, Zeolite, Natural Australian Zeolite, Ion-Exchange

? Liu, C.H. and Lo, K.V. (2001), Ammonia removal from compost leachate using zeolite. III. Regeneration of zeolite columns. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering, 36 (10), 1825-1843.

Full Text: 2001\J Env Sci Hea Par A-Tox Haz Sub Env Eng36, 1825.pdf

Abstract: The effects of hydraulic reteneration time (HRT), and the strength of the regenerating solution on the ammonia adsorption capacity and the zeolite regeneration were studied using bench-scale packed zeolite columns. A 0.6 M NaCl solution fed at a HRT of 1 h was preferred for the regeneration process, and more than 95% of adsorbed ammonium ions were recovered after using 7-8 bed volumes (BV) of the regenerating solution. The adsorption-regeneration time ratio was approximately 5:1. High concentration of potassium ions in the composting leachate competed with NH₄⁺ ions for the exchange sites, resulting in a reduction in the efficiencies of ammonia removal and zeolite column regeneration. However, Zeolite still proved to have a great potential as a medium for ammonia removal in treating composting leachate.

Keywords: Adsorption, Ammonia Removal, Capacity, Column Regeneration, Compost, Compost Leachate, NaCl, Natural Australian Zeolite, Removal, Solution, Zeolite

Stefanova, R.Y. (2001), Removal of lead ions by keramzite sand coated with electroplating sludge under dynamic conditions. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering,