Title: Water Pollution Control

Title: Water Pollution Control

Full Journal Title: Water Pollution Control

ISO Abbreviated Title:

JCR Abbreviated Title:

ISSN:

Issues/Year:

Language:

Publisher:

Publisher Address:

Subject Categories:

: Impact Factor

Lowe, W. (1970), The origin characteristics of toxic wastes, with particular reference to the metal industries. Water Pollution Control, 69, 270-280.

Chalmers, R.K. (1970), Pretreatment of toxic wastes. Water Pollution Control, 69, 281-291.

Chiu, H.S.S. and Lee, R.M.L. (1987), Treatment of electroplating wastes. Water Pollution Control, 86, 12-19.

Title: Water Pollution VIII: Modelling, Monitoring and Management

ISO Abbreviated Title:

JCR Abbreviated Title:

ISSN:

Journal Country/Territory:

Language:

Publisher:

Publisher Address:

Subject Categories:

Impact Factor

Conference Information: 8th International Conference on Modelling, Monitoring and Management of Water Pollution

Bologna, ITALY, SEP, 2006

Wessex Inst Technol; Univ Coimbra; WIT Transact Ecol & Environm

Book Series: Wit Transactions on Ecology and the Environment

Editor(s): Brebbia, C.A., AntunesDoCarmo, J.S.

? O’Connell, D.W., Birkinshaw, C. and O’Dwyer, T.F. (2006), Design of a novel cellulose-based adsorbent for use in heavy metal recovery from aqueous waste streams. Water Pollution VIII: Modelling, Monitoring and Management, 95, 489-498.

Conference Information: 8th International Conference on Modelling, Monitoring and Management of Water Pollution

Abstract: Currently, significant metal-laden waste streams are produced from a number of industries with obvious consequences for the environment. A variety of techniques are being used to treat these wastewaters. One such technique is adsorption and recent focus in this area has been around the preparation of selective adsorbents based on naturally occurring support materials. In our work, a regenerated cellulose wood pulp was grafted with the vinyl monomer glycidyl methacrylate (GMA) and was further functionalised with imidazole to produce a novel adsorbent material, cellulose-g-GMA-imidazole. A series of adsorption studies were carried out on the cellulose-g-GMA-imidazole to assess its capacity in the separate removal of lead and nickel ions (Pb(II), Ni(II)) from aqueous solution. Cellulose-g-GMA-imidazole sorbent showed an uptake of approximately 72 mg g(-1) of Pb(II) and 45 mg g(-1) of Ni(II) from aqueous solution. The adsorption process in both cases followed the Langmuir model of adsorption and Pb(II) uptake occurred within 30 minutes while Ni(II) uptake was considerably slower at 400 minutes for maximum uptake. In both cases pseudo second order kinetics best describes the overall process for each metal uptake. The cellulose-g-GMA-imidazole material shows significant promise as a sorbent for the removal of both Ni(II) and Pb(II) and other heavy metal ions from aqueous and waste streams.

Keywords: Aqueous Waste Streams, Heavy Metals, Cellulose, Adsorption, Activated Carbon, Adsorption, Removal, Ions, Lead(II), Equilibrium, Behavior, Cu(II), Shells, Ni(II)

Title: Water Quality Professional

Title: Water Quality Research Journal of Canada

ISO Abbreviated Title: Water Qual. Res. J. Canada

JCR Abbreviated Title: Water Qual Res J Can

ISSN: 1201-3080

Issues/Year: 4

Journal Country/Territory: Canada

Language: English

Publisher: Canadian Assoc Water Quality

Publisher Address: C/O Dr H R Eisenhauer, Environmental Technol Centre, 3439 River Road South, Gloucester, Ontario K1A 0H3, Canada

Subject Categories:

Water Resources: Impact Factor 1.217, 6/50 (2001); Impact Factor 0.698, 19/53 (2002); Impact Factor 0.946, 15/55 (2003); Impact Factor 0.733, 28/55 (2004); Impact Factor 0.817, 33/57 (2005); Impact Factor 0.708, 43/59 (2007)

? Al-Asheh, S. and Duvnjak, Z. (1999), Sorption of heavy metals from synthetic metalsolutions and industrial wastewater using plant materials. Water Quality Research Journal of Canada, 34 (3), 481-503.

Full Text: 1999\Wat Qua Res J Can34, 481.pdf

Abstract: In a batch process, canola meal, pine bark and moss decreased the copper concentration in an industrial wastewater from a copper refining/smelting plant from 36.5 to 2.5, 4.1 and 5.2 ppm, respectively, when the concentration of each sorbent was 15 mg/mL. pH-controlled tests showed greater Cu²⁺ removal compared to those without pH control The copper concentration was decreased to below its permissible upper limit for drinking water when the wastewater was treated with 9.2 mg/mL of bark at pH 5.2 followed by sorption with 2.3 mg/mL of activated carbon This study also showed that the same total amount of sorbent used either in a single-or multistage sorption process resulted in the same level of copper removal. The removal of copper from the wastewater was also studied using columns packed with bark. After three sorption/desorption cycles, the copper concentration was decreased to 4 ppm. This study also examined the mechanisms of metal biosorption by moss using analytical solutions. Scanning electron microscopy and energy-dispersive X-ray microanalyses revealed that metal ions were sorbed mainly at the cell wall of the moss and only a small amount of ions diffused into the cytoplasm. Both the energy dispersive X-ray analysis and the atomic absorption spectrophotometry measurements showed that ion exchange was an important mechanism in this sorption process.

Keywords: Activated Carbon, Adsorption, Bark, Biosorption, Canola Meal, Copper, EDX, Heavy Metals, Ion Exchange, Mechanism, Metal, Metal Ions, Metals, Moss, pH, Pine Bark, Removal, Rhizopus-arrhizus Biomass, SEM, Sorbent, Sorption

Viraraghavan, T. and Ramakrishna, K.R. (1999), Fly ash for colour removal from synthetic dye solutions. Water Quality Research Journal of Canada, 34 (3), 505-517.

Full Text: 1999\Wat Qua Res J Can34, 505.pdf

Abstract: Fly ash was investigated for its ability to adsorb dyes from aqueous solutions. Batch pH, kinetic and isotherm studies were performed on a laboratory scale with synthetic dye solutions made up of four different commercial grade dyes. Fly ash samples with differing compositions and particle sizes were employed to understand the effect of fly ash composition and particle size on their dye removal capacity. The first-order rate equation by Lagergren was tested on the kinetic data, and isotherm data was analyzed for possible agreement with the Langmuir and Freundlich adsorption isotherm equations. The removal capacity of fly ash for the different dyes was compared with that of granular activated carbon under identical conditions. Results showed that fly ash exhibited reasonably good dye removals for Basic Blue 9, Acid Blue 29 and Acid Red 91 while the removals by fly ash exceeded that of granular activated carbon for Disperse Red 1. Lime content in fly ash seemed to influence dye adsorption to a significant degree-better adsorption was observed at lower particle sizes because of the increased external surface area available for adsorption. Acid Blue 29 adsorption by fly ash provided the best fit for the Lagergren first-order plot. Because high pH and heavy metals (leached from fly ash) in the treated wastewater may exceed the limits set in municipal sewer-use bylaws, engineering and economic feasibility assessment should include these aspects when considering fly ash for colour removal.

Keywords: Fly Ash, Colour Removal, Isotherm Kinetics, Dye Solutions

Fu, Y.Z. and Viraraghavan, T. (2000), Removal of a dye from an aqueous solution by the fungus Aspergillus niger. Water Quality Research Journal of Canada, 35 (1), 95-111.

Full Text: 2000\Wat Qua Res J Can35, 95.pdf

Abstract: Biosorption is becoming a promising alternative to replace or supplement the present dye removal processes from dye wastewater. In this study, removal of a dye, Basic Blue 9, from an aqueous solution by biosorption on the dead fungal biomass Aspergillus niger was studied. The effective pretreatment method for increasing the biosorption capacity of A. niger was investigated. Autoclaving was found to effectively enhance the biosorption capacity of A. niger to 18.54 mg/g compared with 1.17 mg/g of living cells for Basic Blue 9. Batch pH, kinetic and isotherm studies were conducted to evaluate the biosorption capacity of the pretreated (dead) biomass. The initial pH of the dye solution strongly affected the biosorption capacity and rate. The effective initial pH was between 4 and 6. The equilibrium time varied with the initial pH of the dye solution and was set at 30 h because no significant dye removals occurred after that time of contact The Lagergren and Ho et al. models can be used to describe the kinetics of Basic Blue 9 biosorption on A, niger successfully for different initial pH values, except for pH 4. At initial pH 4, biosorption of Basic Blue 9 fitted the Langmuir equation well; at initial pH 10, the Langmuir and Freundlich isotherm models both fitted biosorption well. The results of this study indicated that fungal biomass of A. niger can be used for removing Basic Blue 9 from an aqueous solution.

Keywords: Waste-Water, Color Removal, Decolorization, Biosorption, Effluents, Biomass, Wastewaters, Adsorption, Adsorbent, Biosorption, Aspergillus niger, Basic Blue 9

? Singh, K.S. and Viraraghavan, T. (2000), Performance of UASB reactors at 6 to 32°C in municipal wastewater treatment. Water Quality Research Journal of Canada, 35 (1), 113-124.

Full Text: 1999\Wat Qua Res J Can35, 113.pdf

Abstract: The feasibility of using a high-rate upflow anaerobic sludge blanket (UASB) system for the treatment of low-strength municipal wastewater at 6 to 32°C was investigated for temperate climate applications. UASB reactors could be started up successfully in about 60 days at 20°C. Under stable conditions, the removal of GOD, BOD and SS ranged from 38 to 90%, 47 to 91% and 50 to 92%, respectively, for a temperature range of 6 to 32°C. Sulfate reduction ranged from 10 to 90%, showing a decreasing trend with a decrease in temperature at each HRT. The average biogas production and methane content ranged from 167 to 199 mt CH₄/g-CODremoved and 65 to 86%, respectively. The recovery of methane in the gas phase was very low compared with soluble COD removals, especially during operation at lower temperatures (6 to 15°C). Digital image analysis and scanning electron microscopy results indicated the aggregation of biomass in the form of flocs and small granules. The mean size of aggregated sludge particles increased from 0.2 to 3.0 mm, with a sludge volume index of 18±2 mL/g during the operation.

Keywords: UASB Reactor, Municipal Wastewater, Low Temperature, Anaerobic Treatment, Anaerobic Treatment, Water Treatment, Sewage, Temperatures

? Thirunavkukkarasu, O.S., Viraraghavan, T. and Subramanian, K.S. (2001), Removal of arsenic in drinking water by iron oxide-coated sand and ferrihydrite: Batch studies. Water Quality Research Journal of Canada, 36 (1), 55-70.

Full Text: 2001\Wat Qua Res J Can36, 55.pdf

Abstract: Arsenic, a common toxic element is mainly transported in the environment by water. Arsenic in drinking water is of major concern to many of the water utilities in the world. Numerous studies have examined the removal of arsenic from drinking water through treatment processes such as coagulation-precipitation, reverse osmosis and ion exchange. The focus of research has now shifted to solve the problems using suitable adsorbents to achieve low level As in drinking water for communities with high raw water arsenic concentration The determination of arsenic species is also essential for a better understanding and prediction of the toxic and carcinogenic nature of the species present in natural water systems. It is generally known that As(III) is more toxic than As(V) and inorganic arsenicals are more toxic than organic derivatives. The objective of this study was to study the arsenic adsorption behaviour on iron oxide-coated sand (IOCS) and ferrihydrite (FH). Batch studies were conducted using these adsorbents with natural water containing 325 µg/L arsenic, and the removal of approximately 90% was obtained. The adsorption capacity of the IOCS and FH used in this study for arsenic was estimated as 18.3 and 285 µg/g respectively. The experimental data fitted well with the well-known isotherms, namely, Freundlich, Langmuir and BET, indicating a favourable adsorption by these adsorbents. Speciation studies were also conducted with natural water containing arsenic. Particulate and soluble arsenic in water were determined, and As(III) in the sample was determined by passing the sample containing arsenic through anion exchange resin (Dowex 1X8-100; acetate form) packed in the column. Speciation studies with natural water showed that the particulate and soluble arsenic contributed 11.4 and 88.6% of the total arsenic present in the natural water, respectively. In the case of soluble arsenic, As(III) and As(V) were 47.3 and 52.7%, respectively.

Keywords: Arsenic, Drinking Water, Treatment, Adsorption, Isotherm, Speciation, British-Columbia, Natural-Waters, West-Bengal, Adsorption, Hydroxide, Coagulation, Groundwater, People, North, India

? Fiset, J.E., Tyagi, R.D. and Blais, J.F. (2002), Cocoa shells as adsorbent for metal recovery from acid effluent. Water Quality Research Journal of Canada, 37 (2), 379-388.

Full Text: 2002\Wat Qua Res J Can37, 379.pdf

Abstract: Cocoa shells are commonly used in the horticulture field. This inexpensive substrate was studied for metal removal from acidic effluents. Batch adsorption tests in shake flasks revealed that cocoa shells were particularly efficient for lead removal. More than 90% of lead could be removed from a mono-metallic solution containing 51.8 mg Pb/L (250 M Pb) using 20 g/L of cocoa shells. Langmuir isotherm indicated that cocoa shells have a maximum lead uptake of 7.56 mg/g (36.5 mol/g) at pH = 2.0. Adsorption tests were also successfully completed with three types of heavily contaminated acid effluents: a multi-element synthetic solution and effluents produced during sewage sludge and soil decontamination. These tests have shown that the presence of other metals and organic matter only slightly decreases the lead removal by cocoa shells. After adsorption, metals could be eluted using a diluted acid solution (0.5 N) and the cocoa shells could be reused for many adsorption/desorption cycles.

Keywords: Cocoa Shells, Metals, Adsorption, Lead, Metal Removal, Acid Effluent, Amorphous Iron Oxyhydroxide, Heavy-Metals, Aqueous-Solutions, Adsorption, Ions, Water, Cu, Pb, Zn, Cd

? Watson, S.B. and Lawrence, J. (2003), Drinking water quality and sustainability. Water Quality Research Journal of Canada, 38 (1), 3-13.

Full Text: 2003\Wat Qua Res J Can38, 3.pdf

Keywords: Banff-National-Park, Groundwater, Canada, Chemicals, Future

? Darbi, A., Viraraghavan, T., Jin, Y.C., Braul, L. and Corkal, D. (2003), Sulfate removal from water. Water Quality Research Journal of Canada, 38 (1), 169-182.

Full Text: 2003\Wat Qua Res J Can38, 169.pdf

Abstract: Sulfate occurs naturally in groundwater. Concerns regarding the health effects from sulfate in drinking water have been raised because of reports that diarrhea may be associated with water that contains high levels of sulfate. In the livestock Production industry, there is a concern that high levels of sulfate in water can adversely affect productivity. Different methods can be used to remove sulfate from water. Proven technologies are ion-exchange, nanofiltration, reverse osmosis, and electrodialysis. A few earlier studies have shown that the use of bentonite/kaolinite for sulfate removal has produced encouraging results. Experimental work was undertaken to examine in detail the feasibility of such processes. Laboratory studies using bentonite showed poor or no removal in the case of high sulfate water. Ion exchange and nanofiltration were found to be very effective in removing sulfate. Ion exchange is likely to be more reliable than nanofiltration because of the sensitivity of the nanofiltration process to total dissolved solids and biofouling.

Keywords: Sulfate Removal, Drinking Water, Bentonite, Ion Exchange, Nanofiltration, Drinking-Water

? Darbi, A. and Viraraghavan, T. (2003), A kinetic model for autotrophic denitrification using sulphur: Limestone reactors. Water Quality Research Journal of Canada, 38 (1), 183-192.

Full Text: 2003\Wat Qua Res J Can38, 183.pdf

Abstract: The kinetics of autotrophic denitrification of groundwater by Thiobacillus denitrificans in a sulfur: limestone upflow reactor was examined in order to predict effluent concentrations. Experiments were performed using-water containing 60 and 90 mg NO₃-N/L and sulfur and limestone with average particle size of 3.5 mm. Results clearly showed that nitrate was completely removed from 60 and 90 mg NO₃-N/L influent concentrations. The results showed that the autotrophic denitrification rates in sulfur: limestone reactors can be described by half-order kinetics. The half-order reaction rate constants for the entire media were estimated at 1.34 and 1.54 mg(1/2)/L-1/2 h for influent concentrations of 60 and 90 mg NO₃-N/L, respectively.

Keywords: Autotrophic Denitrification, Nitrate Removal, Thiobacillus Denitrificans, Sulfur, Limestone, Drinking Water, Kinetics, Nitrate Removal

? Manna, B.R., Dey, S., Debnath, S. and Ghosh, U.C. (2003), Removal of arsenic from groundwater using crystalline hydrous ferric oxide (CHFO). Water Quality Research Journal of Canada, 38 (1), 193-210.

Full Text: 2003\Wat Qua Res J Can38, 193.pdf

Abstract: Synthesis of crystalline hydrous ferric oxide (CHFO), a modified iron-based adsorbent, and its arsenic sorption behaviour have been reported. Here, the effects of pH with variation of arsenic concentrations, contact time, pre-drying of CHFO, competition of some other anions and regeneration of arsenic-saturated CHFO are conducted by batch method. The sorption of As(V) is highly dependent on the concentration and pH of the experimental system, while that for As(III) is pH insensitive. As(III) is found to require less contact time to attain equilibrium than that of arsenic(V). Pre-drying of CHFO in the temperature range of 200 to 300degreesC is found to be effective in removing both MUM and As(V). Adsorption kinetics follow the first-order Lagergren model. The equilibrium data conform to the Langmuir isotherm. Evaluated Langmuir constants and equilibrium parameter (R-L) indicate that CHFO is a better As(III) adsorbent under experimental conditions. Sulphate, phosphate and bicarbonate compete poorly with As(III) sorption. A field test using CHFO-packed fixed-bed column is reported. Effluent water bed volumes of 14,000, 11,000 and 9000 BV (arsenic less than or equal to 0.01 mg L^-1) were obtained in the first, second and third cycle of operation from a groundwater sample (arsenic content: 320400 mug L^-1). Regeneration of the exhausted column was achieved with up to 80 to 85% efficiency using 3 BV of 5 M NaOH solution recycled through the column five times. Arsenic was recovered as As2S3 from the regenerates, to avoid recycling of arsenic into the environment.

Keywords: Adsorption, Aluminum, Arsenic, As(V), Column, Crystalline Ferric Oxide, Environment, Ferrihydrite, Fixed Bed, Fixed Bed Column, Fixed-Bed Column, Goethite, Groundwater, Hydroxide, Kinetics, Model, Oxidation, Recovery, Regeneration, Removal, Sorption, Water

? Tahiri, S., Messaoudi, A., Albizane, A., Azzi, M., Bouhria, M., Younssi, S.A., Bennazha, J. and Mabrour, J. (2003), Removal of dyes from aqueous solutions by adsorption on chrome-tanned solid wastes generated in the leather industry. Water Quality Research Journal of Canada, 38 (2), 393-411.

Full Text: Wat Qua Res J Can38, 393

Abstract: In this work, the ability of chrome shavings and of crust leather buffing dusts to remove dyes from aqueous solutions has been studied. Buffing dusts proved to be a much better adsorbent than chrome shavings for cationic dyes. The adsorption of anionic dyes is very important on two studied wastes. The pH has an obvious influence on the adsorption of dyes. Adsorption of cationic dyes is less favourable under acidic conditions (pH < 3.5) and at high pH values (pH > 10.5). The adsorption of anionic dyes on both adsorbents is more favourable under acidic conditions (pH < 3). The adsorption on chrome shavings is improved by the use of finer particles. The kinetic adsorption was also studied. Adsorption isotherms, at the optimum operating conditions, were determined. Adsorption follows the Langmuir model. The isotherm parameters have been calculated. The column technique could be applied to treat significant volumes of solutions.

Keywords: Activated-Sludge, Adsorbent, Adsorption, Anionic Dyes, Buffing Dusts, Cake, Carbon, Cationic Dyes, Chrome Shavings, Dyes, Langmuir, Particles, Pigment, Pilot-Scale, Recovery, Shavings, Water

? Mathialagan, T., Viraraghavan, T. and Cullimore, D.R. (2003), Adsorption of cadmium from aqueous solutions by edible mushrooms (Agaricus bisporus and Lentinus edodes). Water Quality Research Journal of Canada, 38 (3), 499-514.

Full Text: 2003\Wat Qua Res J Can38, 499.pdf

Abstract: Fungal organisms can remove heavy metals from aqueous solutions. Macro fungi such as Agaricus bisporus and Lentinus edodes (shiitake), commonly called mushrooms, are edible and are grown commercially. Laboratory batch studies were conducted at room temperature (21±1degreesC) to determine the potential of these fungal biomasses for adsorption of cadmium from aqueous solutions containing 1 mg/L cadmium. Results from batch studies showed that biomasses prepared from A. bisponts and L. edodes had good potential for removing cadmium from aqueous solutions. The maximum adsorption capacity of A. bisporus and L. edodes for uptake of cadmium from aqueous solutions was 2.08 and 0.716 mg/g, respectively. The equilibrium time for adsorption was found to be 6 and 1 h for A. bisporus and L. edodes, respectively. 68% cadmium removal was achieved with A. bisporus and 45% with L. edodes. The optimum initial pH was found to be 6.0 and 5.0 for A. bisporus and L. edodes, respectively. Isotherm studies suggested that cadmium adsorption by both the mushrooms followed the Freundlich isotherm. Desorption of cadmium from mushrooms by dilute HCL was minimal (19%), but rapid

Keywords: Activated Carbon, Adsorption, Agaricus Bisporus, Binding, Biosorption, Cadmium, Copper, Fly-Ash, Fruiting Bodies, Lentinus Edodes, Metals, Mushrooms, Peat, Removal, Water

? Sanghi, R. and Bhattacharya, B. (2003), Adsorption-coagulation for the decolorisation of textile dye solutions. Water Quality Research Journal of Canada, 38 (3), 553-562.

Full Text: 2003\Wat Qua Res J Can38, 553.pdf

Abstract: Studies were undertaken for the removal of colour from different types of synthetic dye solutions by using powdered activated carbon (PAC) and bentonite clay (BC) as adsorbents. The different types of dyes (direct, mordant and basic) studied were Direct Orange, Eriochrome Black T and Malachite Green. The synthetic dye solutions behaved differently with the two adsorbents. The effect of adsorption by PAC and the further addition of a very small dose of a coagulant polyaluminium chloride (PAIC) on the settling and/or reuse of adsorbents used was studied. PAC and BC, though effective adsorbents, remained suspended in the solution for a long time. PAIC not only enhanced dye removal, but also formed a sludge that settled very quickly and which could also be reused effectively for dye removal.

Keywords: Powdered Activated Carbon, Polyaluminium Chloride, Dye, Adsorption, Coagulation, Activated Carbon, Contact-Time, Removal, Color

? Davis, T.A., Ali, F.E., Giannitti, E., Volesky, B. and Mucci, A. (2004), Cadmium biosorption by S. fluitans: Treatment, resilience and uptake relative to other Sargassum spp. and brown algae. Water Quality Research Journal of Canada, 39 (3), 183-189.

Full Text: 2004\Wat Qua Res J Can39, 183.pdf

Abstract: Species of the brown algae Sargassum have been targeted for use in the implementation of strategies to remediate toxic heavy metal contamination in effluents and drinking waters. This work focusses on some of the intrinsic physico-chemical properties of the algal material and aspects of the sorption mechanism, in particular: their maximal metal uptake, the influence of particle size and their resilience to leaching during equilibrium batch experiments. In addition to S. fluitans, the database on cadmium uptake capacities by Sargassum is extended to include S. thunbergii and S. oligocystum, and these are compared to those of two common brown algae. Results of our experiments demonstrate that cadmium sorption is independent of the range of particle sizes investigated (<2 and 3-6 mm), thereby indicating that sorption is not a function of the specific surface area of the biomass exposed to the solution. Dissolved organic carbon (DOC) analyses reveal that leaching to the cadmium solutions during the metal sorption reaction is independent of the biomass preparations used to obtain the two size fractions but decreases with increasing final cadmium concentration.

Keywords: Alginate, Biosorption, Cadmium, Sargassum Fluitans, Sargassum Thunbergii, Sargassum Oligocystum, Leaching, Heavy-Metal Biosorption, Great-Barrier-Reef, Exchange Properties, Ionic-Strength, Alginate, Biomass, Seaweed, Column, Protons, H-1-NMR

Zeng, L. (2004), Arsenic adsorption from aqueous solutions on an Fe(III)-Si binary oxide adsorbent. Water Quality Research Journal of Canada, 39 (3), 269-277.

Full Text: W\Wat Qua Res J Can39, 269.pdf

This study investigated arsenate and arsenite adsorption on an iron(III) oxide/silica adsorbent that had a Fe/Si molar ratio of 3. Batch experiments were conducted with regard to adsorption kinetics, isotherms, pH effects and interference of phosphate and sulfate on arsenic adsorption. The adsorption of arsenite was faster than that of arsenate. The adsorption kinetics could be well described by the power function equation for both arsenate and arsenite. The arsenate and arsenite adsorption isotherm data were satisfactorily fitted by the Redlich-Peterson, Freundlich-Langmuir and Langmuir models. The equilibrium adsorption capacity for As(III) was larger than that for As(V). This capacity for both As(III) and As(V) increased with temperature, from 11.3 to 14.9 (mg As/g) for As(V) and from 21.1 to 21.5 (mg As/g) for As(III) when the temperature was increased from 20 to 35ºC. The arsenate adsorption was significantly reduced at pH above 7.5, while the arsenite adsorption was almost independent of pH in the range of 3 to 9. The calculated thermodynamic parameters including ∆Gº, ∆Hº and ∆Sº reflected the spontaneous nature of As(V) and As(III) adsorption on this binary oxide adsorbent. The opposite values of ∆Hº indicated that the adsorption of As(V) was exothermic, whereas that of As(III) was endothermic. It was found that the interference of phosphate at pH 7.4 was more significant for arsenate adsorption than for arsenite adsorption. In contrast, sulfate had insignificant interference on arsenic adsorption at the tested sulfate concentration up to 460 mg/L and pH 7.4.

Keywords: Arsenic Adsorption, Equilibrium, Kinetics, Isotherm, Hydrous Ferric Oxide, Silica

? Manna, B. and Ghosh, U.C. (2005), Pilot-scale performance of iron and arsenic removal from contaminated groundwater. Water Quality Research Journal of Canada, 40 (1), 82-90.

Abstract: Pilot-scale performance in reducing excess iron and arsenic from contaminated groundwater has been systematically reported. Here, a double column unit, the first packed with β-MnO₂ and the second with crystalline FeOOH (goethite variety), with filters attached to the outlet of hand-pump tube-wells has been used in the field. Results showed that the filters generate 10,000 to 15,000 BV and 19,000 to 35,000 BV water with iron &LE; 0.3 mg, L and arsenic &LE; 10 μ g, L from groundwater having influent iron and arsenic levels of 3.75 to 7.25 mg, L and 70 to 220 μ g, L, respectively. The downflow rate of effluent water was 237.6 to 305.5 L, m²-Min. The performance results were achieved with a single charging of the iron and arsenic removal media. Toxicity characteristic leaching procedure (TCLP) tests of the waste (arsenic content: 2.4 g, kg) showed that it is not hazardous to the environment and does not pose any risk to users. Cost evaluation showed $US0.50 to 0.70 per 1000 gallons of treated water and, hence, the technology is cost-effective for countries such as India and Bangladesh.

Keywords: Adsorption, Arsenic, Bangladesh, Fixed Bed Adsorbent, Groundwater, Iron, Kinetics, Low-Cost, Mechanisms, Natural-Waters, Oxidation, Oxide-Coated Sand, Pilot-Scale, Removal, West-Bengal

? Al-Asheh, S., Banat, F. and Masad, A. (2005), Use of activated oil shale for the removal of 2,4-dichlorophenol from aqueous solutions. Water Quality Research Journal of Canada, 40 (2), 211-221.

Full Text: 2005\Wat Qua Res J Can40, 211.pdf

Abstract: Sorption of the phenolic compound 2,4-dichlorophenol (2,4-DCP) by pyrolyzed and different forms of treated residue of Jordanian oil shale was examined. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520°C in the presence of nitrogen. Physical activation was carried out by treating the resultant pyrolyzed oil shale with CO₂ at 830°C, while chemical activation of oil shale was carried out using KOH and ZnCl₂ as impregnating agents. Uptake of 2,4-DCP onto the different types of sorbents increased in the order ZnCl₂-OS > Pyr-OS > CO₂-OS, with minimal uptake when KOH-OS was used. The process was found to be exothermic in nature. An increase in the initial pH of the solution negatively influenced the sorption of 2,4-DCP. The isotherm experimental data fitted reasonably to the Langmuir, Freundlich and Redlich-Paterson models. According to kinetics studies, the rate of 2,4-DCP sorption onto ZnCl₂-OS was faster than that by Pyr-OS. Three kinetics models, namely the Morris-Weber model, Lagergren model, and pseudo-second-order model (PSOM), were applied to represent the experimental results for both pyrolyzed and ZnCl₂-oil shale sorbents.

Keywords: Oil Shale, Physical Activation, Chemical Activation, 2,4-Dichlorophenol, Phenolic-Compounds, Adsorption-Isotherms, Chlorinated Phenols, Substituted Phenols, Fly-Ash, Carbon, Kinetics, Sorption, Chlorophenols, Residue

? Singh, T.S. and Pant, K.K. (2006), Kinetics and mass transfer studies on the adsorption of arsenic onto activated alumina and iron oxide impregnated activated alumina. Water Quality Research Journal of Canada, 41 (2), 147-156.

Full Text: Wat Qua Res J Can41, 147

Abstract: The present investigation deals with the uptake of As(III) and As(V) ions from aqueous solution by activated alumina and a new laboratory-prepared sorbent-iron oxide impregnated activated alumina. Iron oxide impregnation onto activated alumina significantly increased the percent arsenic removal and adsorption capacity for As(III) and As(V) ions. The maximum As(III) and As(V) removals were 96.8% and 98.4%, respectively, by iron oxide impregnated activated alumina (IOIAA). Maximum As(III) and As(V) removal of 94.2% and 96.1% was observed over activated alumina. Kinetic studies were performed at different initial sorbate concentrations to determine the mechanism of mass transfer of sorbate onto this sorbent. The maximum removal of As(III) and As(V) by activated alumina and iron oxide impregnated alumina takes place within 6 h and attains equilibrium within 12 h. First-order Lagergren kinetics explained the adsorption of arsenic over activated alumina whereas a pseudo-second order rate equation explained the behaviour of As(III) adsorption over iron oxide impregnated activated alumina. Diffusional. effects in solid pellets were also investigated to understand the mechanism of adsorption. These results indicate that the mechanism of arsenic adsorption is complex on both sorbents as both pore diffusion and surface diffusion contribute to the arsenic removal. During the initial period, surface diffusion was predominant but as the adsorption progresses, pore diffusion dominated the rate of adsorption.

Keywords: Arsenic, Diffusion, Adsorption, Kinetics, Iron Oxide, Drinking-Water, Aqueous-Solution, West-Bengal, Affected People, Ground-Water, Coated Sand, 6 Districts, Fly-Ash, Removal, As(III)

? Ghosh, U.C., Bandyopadhyay, D., Manna, B. and Mandal, M. (2006), Hydrous iron(III)-tin(IV) binary mixed oxide: Arsenic adsorption behaviour from aqueous solution. Water Quality Research Journal of Canada, 41 (2), 198-209.

Full Text: Wat Qua Res J Can41, 198

Abstract: Groundwater in the Bengal delta plain is primarily in an anoxic environment and As(III)/As(total) ratios reported are in the range of 0.60 to 0.90. Most of the studied adsorbents showed greater adsorption affinity for less toxic As(V) than for more toxic As(III). The synthesis and physicochemical characterizations of iron(III)-tin(IV) binary mixed oxide composite with systematic arsenic adsorption behaviour are reported here. The parameters studied are the effect of pH, adsorption capacity with varying arsenic loads, contact time for kinetics and isotherm modelling by batch method. In the pH range of 3.0 to 9.0, the adsorption of As(III) is found to be nearly the same while that of As(V) decreases with increasing pH for the studied arsenic concentrations (5.0 to 20.0 mg L^-1). The adsorption data were analyzed using various kinetic and isotherm model equations. The rate of adsorption of As(III) was faster than that of As(V) at equilibrium pH similar to 7.0 and temperature 302C. The adsorption kinetic data for arsenic fitted best with the Ho’s pseudo-second order [R² similar to 0.99-1.00 for As(III) and similar to 0.97-0.98 for As(V)] and parabolic diffusion (R² similar to 0.98-0.99) equations. The present kinetic data fitted the power function and simple Elovich kinetic equations well (R² = similar to 0.97-1.00), except the data obtained for As(III) from the 20.0 mg 1:1 solution. The analyses of adsorption data for As(III) and As(V), respectively, at equilibrium PH 6.80.1 and 7.30.1 with three different two-parameter isotherm model equations show the fitting order: Langmuir > Freundlich > Temkin. The monolayer adsorption capacity (theta(0), mg g^-1) values evaluated from the Langmuir isotherm for As(III) and As(V) are 43.86 and 27.55, respectively.

Keywords: Arsenic, Adsorption, Hydrous Iron(III)-Tin(IV) Mixed Oxide, Isotherm, Kinetics, pH, Granular Ferric Hydroxide, Drinking-Water, Natural-Waters, Coated Sand, Removal, Ferrihydrite, Groundwater, Aluminum