Personal Research Database

Full Text: J\J Haz Mat113, 217.pdf

Abstract: Hexavalent chromium is a common and toxic pollutant in soils and wastewaters. Reduction of the mobile Cr(VI) to less mobile and less toxic Cr(III) is a solution for decontamination of industrial effluents. In this study, the reduction of hexavalent chromium in aqueous solutions by siderite was investigated. The influences of amount of acid, contact time, siderite dosage, initial Cr(VI) concentration, temperature and particle size of siderite have been tested in batch runs. The process was found to be acid, temperature and concentration dependent. The amount of acid is the most effective parameter affecting the Cr(VI) reduction since carbonaceous gangue minerals consume acid by side reactions. The highest Cr(VI) reduction efficiency (100%) occurred in the 50 mg/l Cr(VI) solution containing two times acid with respect to stoichiometric amount of Cr(VI) and at the conditions of siderite dosage 20 g/l, contact time 120 min and temperature 25 °C. Reduction efficiency increased with increase in temperature and decrease in particle size. The reduction capacity of siderite was found to be 17 mg-Cr(VI)/g.

Keywords: Hexavalent Chromium, Reduction, Heavy Metal, Siderite

Vijayaraghavan, K., Jegan, J., Palanivelu, K. and Velan, M. (2004), Removal of nickel(II) ions from aqueous solution using crab shell particles in a packed bed up-flow column. Journal of Hazardous Materials, 113 (1-3), 223-230.

Full Text: J\J Haz Mat113, 223.pdf

Abstract: This paper investigates the ability of crab shell to remove nickel(II) ions from aqueous solution in a packed bed up-flow column with an internal diameter of 2 cm. The experiments were performed with different bed heights (15–25 cm) and using different flow rates (5–20 ml/min) in order to obtain experimental breakthrough curves. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. The column regeneration studies were carried out for seven sorption–desorption cycles. The elutant used for the regeneration of the sorbent was 0.01 M EDTA (disodium) solution at pH 9.8 adjusted using NH₄OH. Due to continuous usage of crab shell, a performance loss was observed as the breakthrough curves become more flattened also indicated by the broadened mass transfer zone. The breakthrough time decreased uniformly from 28.1 to 9.5 h as the cycles progressed from one to seven, whereas nickel uptake remained approximately constant throughout the seven cycles. The life-factors for crab shell in terms of critical bed length and breakthrough time were found to be 1.1 cm/cycle and 0.17 per cycle, respectively. The elution efficiency was greater than 99.1% in all the seven cycles. The pH profiles during both sorption and desorption process were also reported. In sorption cycles, there was a sudden raise in pH in the early part of the process and then the pH decreased as the time progressed. In desorption cycles, pH decreased in initial stages and followed by gradual increase in pH, which eventually reached the pH of the inlet elutant.

Keywords: Crab Shell, Nickel, Biosorption, Packed Bed Column, Regeneration

Gönen, N., Kabasakal, O.S. and Özdil, G. (2004), Recovery of cyanide in gold leach waste solution by volatilization and absorption. Journal of Hazardous Materials, 113 (1-3), 231-236.

Full Text: J\J Haz Mat113, 231.pdf

Abstract: In this study, the effects of pH, time and temperature in regeneration of cyanide in the leaching waste solution of gold production from disseminated gold ore by cyanidation process were investigated and the optimum conditions, consumptions and cyanide recovery values were determined.

The sample of waste solution containing 156 mg/l free CN⁻ and 358 mg/l total CN⁻, that was obtained from Gümüşhane–Mastra/Turkey disseminated gold ores by cyanidation and carbon-in-pulp (CIP) process under laboratory conditions was used in the experiments. Acidification with H₂SO₄, volatilization of hydrogen cyanide (HCN) with air stripping and absorption of HCN in a basic solution stages were applied and under optimum conditions, 100% of free cyanide and 48% of complex cyanide and consequently 70% of the total cyanide in the liquid phase of gold leach effluent are recovered.

Keywords: Gold Leach, Cyanide Waste Solution, Cyanide Removal, Cyanide Recovery, Regeneration

Lee, C.I., Yang, W.F. and Hsieh, C.I. (2004), Removal of copper(II) by manganese-coated sand in a liquid fluidized-bed reactor. Journal of Hazardous Materials, 114 (1-3), 45-51.

Full Text: J\J Haz Mat114, 45.pdf

Abstract: This study was performed in a fluidized-bed reactor (FBR) filled with manganese-coated sand (MCS) to treat copper-contaminated wastewater. The adsorption characteristics of MCS, the adsorption equilibrium of MCS, and the copper removal capacity by MCS in FBR were investigated. In terms of the adsorption characteristics of MCS, the surface of MCS was evaluated using a scanning electron microscope (SEM). Energy dispersive analysis (EDS) of X-rays indicated the composition of MCS, and the quantity of manganese on MCS was determined by means of acid digestion analysis. The experimental results indicated that copper was removed by both sorption (ion exchange and adsorption) and coprecipitation on the surface of MCS in FBR. Copper removal efficiency was highly dependent on the pH and increased with increasing pH from pH 2 to 8. After the copper adsorption by MCS, the pH in solution was decreased. When the MCS concentration was greater than 10 g/l, the copper adsorptivities obtained by FBR were almost the same as that from the shaker and when the MCS concentration reached 40 g/l, the copper adsorptivity in FBR was greater than that from the shaker. The adsorption sites of MCS could be used efficiently by the FBR. A Langmuir adsorption isotherm equation fit the measured adsorption data from the batch equilibrium adsorption test better than the Freundlich adsorption isotherm equation did. In addition, the adsorption rate increased when the influent wastewater was aerated.

Keywords: Fluidized-Bed Reactor, Copper Removal, Manganese-Coated Sand, Adsorption, Coprecipitation

Oguz, E. (2004), Removal of phosphate from aqueous solution with blast furnace slag. Journal of Hazardous Materials, 114 (1-3), 131-137.

Full Text: J\J Haz Mat114, 131.pdf

Abstract: Blast furnace slag was used to remove phosphate from aqueous solutions. The influence of pH, temperature, agitation rate, and blast furnace slag dosage on phosphate removal was investigated by conducting a series of batch adsorption experiments. In addition, the yield and mechanisms of phosphate removal were explained on the basis of the results of X-ray spectroscopy, measurements of zeta potential of particles, specific surface area, and images of scanning electron microscopy (SEM) of the particles before and after adsorption. The specific surface area of the blast furnace slag was 0.4 m² g⁻¹. The removal of phosphate predominantly has taken place by a precipitation mechanism and weak physical interactions between the surface of adsorbent and the metallic salts of phosphate. In this study, phosphate removal in excess of 99% was obtained, and it was concluded that blast furnace slag is an efficient adsorbent for the removal of phosphate from solution.

Keywords: Adsorption, Phosphate, Blast Furnace Slag

Jha, V.K., Kameshima, Y., Nakajima, A. and Okada, K. (2004), Hazardous ions uptake behavior of thermally activated steel-making slag. Journal of Hazardous Materials, 114 (1-3), 139-144.

Full Text: J\J Haz Mat114, 139.pdf

Abstract: This study concerns the utilization of waste steel-making slag, a by-product that contains mainly CaO, Fe₂O₃ and SiO₂. The as-received slag was ground and thermally activated by temperature treatment from 110 to 1000 °C for 24 h. Although the as-received slag was amorphous, it became partially crystallized during grinding. These crystalline phases were larnite and iron oxide but other crystalline phases also appeared in addition to larnite after calcination. The uptake of Ni²⁺, PO₄³⁻ and NH₄⁺ by the samples was investigated from solutions with initial concentrations of 10 mmol/l. The sample calcined at 800 °C showed the highest Ni²⁺ uptake (4.85 mmol/g) whereas the highest simultaneous uptake of PO₄³⁻ (2.75 mmol/g) and NH₄⁺ (0.25 mmol/g) was achieved by calcining the material at 700 °C. The principal mechanism of Ni²⁺ uptake is thought to involve replacement of Ca²⁺ by Ni²⁺. The mechanism of PO₄³⁻ uptake is mainly by formation of calcium phosphate while that of NH₄⁺ involves sorption by the porous silica surface of the samples.

Keywords: Slag, Temperature Treatment, Ni²⁺, NH₄⁺, PO₄³⁻ Uptake

Batzias, F.A. and Sidiras, D.K. (2004), Dye adsorption by calcium chloride treated beech sawdust in batch and fixed-bed systems. Journal of Hazardous Materials, 114 (1-3), 167-174.

Full Text: J\J Haz Mat114, 167.pdf

Abstract: Batch and column kinetics of methylene blue and red basic 22 adsorption on CaCl₂ treated beech sawdust was investigated, using untreated beech sawdust as control, in order to explore its potential use as a low-cost adsorbent for wastewater dye removal. The adsorption capacity, estimated according to Freundlich’s model, and the adsorption capacity coefficient values, determined using the Bohart and Adams’ bed depth service model indicate that CaCl₂ treatment enhanced the adsorption properties of the original material.

Keywords: Dyes, Adsorption, Wood, Sawdust, Pretreatment, Calcium Chloride, Column Studies

Jain, C.K., Singhal, D.C. and Sharma, M.K. (2004), Adsorption of zinc on bed sediment of River Hindon: Adsorption models and kinetics. Journal of Hazardous Materials, 114 (1-3), 231-239.

Full Text: J\J Haz Mat114, 231.pdf

Abstract: The paper presents a study of zinc adsorption using the experimental data on bed sediments of River Hindon in western Uttar Pradesh (India). The effect of various operating variables, viz., initial concentration, solution pH, sediment dose, contact time, and particle size, have been studied. The optimum contact time needed to reach equilibrium was of the order of 60 min and was independent of initial concentration of zinc ions. The extent of adsorption increased with an increase of pH. Furthermore the adsorption of zinc increases with increasing adsorbent doses and decreases with the adsorbent particle size. The content of iron, manganese and organic matter in various fraction of sediment decreases with increasing particle size indicating the possibility of the two geochemical phases to act as the active support material for the adsorption of zinc ions. The adsorption data follows both Langmuir and Freundlich adsorption models. Isotherms were used to determine thermodynamic parameters, viz., free energy change, enthalpy change and entropy change. The negative values of free energy change indicate spontaneous nature of the adsorption while positive values of enthalpy change suggest the endothermic nature of the adsorption of zinc on bed sediment of the River Hindon. The positive values of entropy change indicate randomness at the solid/solution interface.

Keywords: Adsorption Models, Thermodynamics, Zinc, Sediments, Kinetics

Ho, Y.S. (2004), Comment on “Sorption of basic dyes from aqueous solution by activated sludge” [J. Hazard. Mater. 108 (2004) 183–188]. Journal of Hazardous Materials, 114 (1-3), 241-245.

Full Text: J\J Haz Mat114, 241.pdf J\J Haz Mat-Ho.pdf

Keywords: Fungus Aspergillus-Niger, Heavy-Metal Adsorption, Sugarcane Bagasse Pith, Sphagnum Moss Peat, Kinetic-Models, Tree Fern, Date Pits, Cadmium Ion, Congo-Red, Removal

? Ryder, N.L., Sutula, J.A., Schemel, C.F., Hamer, A.J. and Brunt, V.V. (2005), Consequence modeling using the fire dynamics simulator. Journal of Hazardous Materials, 115 (1-3), 149-154.

Full Text: J\J Haz Mat115, 149.pdf

Abstract: The use of Computational Fluid Dynamics (CFD) and in particular Large Eddy Simulation (LES) codes to model fires provides an efficient tool for the prediction of large-scale effects that include plume characteristics, combustion product dispersion, and heat effects to adjacent objects. This paper illustrates the strengths of the Fire Dynamics Simulator (FDS), an LES code developed by the National Institute of Standards and Technology (NIST), through several small and large-scale validation runs and process safety applications.

The paper presents two fire experiments—a small room fire and a large (15 m diameter) pool fire. The model results are compared to experimental data and demonstrate good agreement between the models and data. The validation work is then extended to demonstrate applicability to process safety concerns by detailing a model of a tank farm fire and a model of the ignition of a gaseous fuel in a confined space. In this simulation, a room was filled with propane, given time to disperse, and was then ignited. The model yields accurate results of the dispersion of the gas throughout the space. This information can be used to determine flammability and explosive limits in a space and can be used in subsequent models to determine the pressure and temperature waves that would result from an explosion. The model dispersion results were compared to an experiment performed by Factory Mutual.

Using the above examples, this paper will demonstrate that FDS is ideally suited to build realistic models of process geometries in which large scale explosion and fire failure risks can be evaluated with several distinct advantages over more traditional CFD codes. Namely transient solutions to fire and explosion growth can be produced with less sophisticated hardware (lower cost) than needed for traditional CFD codes (PC type computer verses UNIX workstation) and can be solved for longer time histories (on the order of hundreds of seconds of computed time) with minimal computer resources and length of model run. Additionally results that are produced can be analyzed, viewed, and tabulated during and following a model run within a PC environment. There are some tradeoffs, however, as rapid computations in PC’s may require a sacrifice in the grid resolution or in the sub-grid modeling, depending on the size of the geometry modeled.

Keywords: CFD, Fire, Fire Dynamics Simulator (FDS), Modeling, Dispersion, Large Eddy Simulation (LES)

? Gioia, F. and Urciuolo, M. (2005), The containment of oil spills in unconsolidated granular porous media using xanthan/Cr(III) and xanthan/Al(III) gels. Journal of Hazardous Materials, 116 (1-2), 83-93.

Full Text: J\J Haz Mat116, 83.pdf

Abstract: The gelation in situ of aqueous solutions of the biopolymer xanthan gum may be a method for temporarily containing oil spills in soil whilst the remediation procedure is planned and accomplished. The gelling reaction has been carried out using as crosslinking agents either Cr(III) or Al(III) cations. By using Cr(III) the gelation time, which has been measured for a range of xanthan and/or Cr(III) concentrations, is of the order of the hour. On the contrary, the gelation by means of Al(III) cations takes place at quite low pH and is instantaneous. Therefore, depending on the crosslinker adopted, rather different techniques must be used for generating the gel structure in situ. The gels have proven to be suitable for the containment of water and of many hydrocarbons without loosing their strength even for a long period of time. The rheological properties of xanthan aqueous solutions evidence a shear-thinning behaviour that is most favourable for the application. Theoretical considerations have permitted the establishment of the mobility conditions of xanthan solutions in porous media before the gelation, and the estimation of a suitable injection pressure. The experiments for investigating the mobility of xanthan solutions in porous media, and for simulating the containment of an oil spill, have been done using packed beds of uniformly sized spherical glass beads, in glass columns. The glass assembly made it possible to visualize the evolution of the phenomena of interest.

Keywords: Containment of Spills in Soil, Gelation Time, Xanthan/Cr(III) Gel, Xanthan/Al(III) Gel, Ease of Injection, Gelled Polymer Technology

Jalali-Rad, R., Ghafourian, H., Asef, Y., Dalir, S.T., Sahafipour, M.H. and Gharanjik, B.M. (2004), Biosorption of cesium by native and chemically modified biomass of marine algae: introduce the new biosorbents for biotechnology applications. Journal of Hazardous Materials, 116 (1-2), 125-134.

Full Text: J\J Haz Mat116, 125.pdf

Abstract: Biosorption batch experiments were conducted to determine the cesium binding ability of native biomass and chemically modified biosorbents derived from marine algae, namely ferrocyanide algal sorbents type 1 and type 2 (FASs1 and FASs2). The applicability of the Langmuir and Freundlich isotherms for representation of the experimental data was investigated. The cesium sorption performances of the various types of sorbents were compared using the maximum capacities (q_max values) obtained from fitting the Langmuir isotherm to the values calculated from the sorption experiments, which FASs type 1 and type 2 showed better sorption performances for cesium. FASs1 and FASs2 derived from formaldehyde and glutaraldehyde crosslinked Padina australis exhibited lower sorption capacities than those prepared from the non-crosslinked one. Most of the cesium ions were bound to FASs1, derived from Sargassum glaucescens and P. australis, in < 2 min and equilibrium reached within the first 30 min of contact. Biosorption of cesium by FASs1 derived from P. australis and Cystoseria indica was constantly occurred at a wide range of pH, between 1 and 10, and the highest removal took place at pH 4. The presence of sodium and potassium at 0.5 and 1 mM did not inhibit cesium biosorption by algae biomass. The maximum cesium uptake was acquired using the large particles of FAS2 originated from S. glaucescens (2–4 mm). Desorption of cesium from the metal-laden FASs1 (from P. australis, S. glaucescens and Dictyota indica) was completely achieved applying 0.5 and 1 M NaOH and KOH, although the cesium sorption capacity of the biosorbents (from C. indica and S. glaucescens) decreased by 46–51% after 9 sorption–desorption cycles.

Keywords: Cesium Biosorption, Desorption, Marine Algae, Ferrocyanide Algal Sorbents, Crosslinked Biomass

Alkan, M., Demirbaş, Ö., Çelikçapa, S. and Doğan, M. (2004), Sorption of acid red 57 from aqueous solution onto sepiolite. Journal of Hazardous Materials, 116 (1-2), 135-145.

Full Text: J\J Haz Mat116, 135.pdf

Abstract: Sepiolite, a highly porous mineral, is becoming widely used as an alternative material in areas where sorptive, catalytic and rheological applications are required. High ion exchange capacity and high surface area and more importantly its relatively cheap price make it an attractive adsorbent. In this study, the adsorption of acid red 57 by natural mesoporous sepiolite has been examined in order to measure the ability of this mineral to remove coloured textile dyes from wastewater. For this purpose, a series of batch adsorption tests of acid red 57 from aqueous sepiolite solutions have been systematically investigated as a function of parameters such as pH, ionic strength and temperature. Adsorption equilibrium was reached within 1 h. The removal of acid red 57 decreases with pH from 3 to 9 and temperature from 25 to 55 °C, whereas it increases with ionic strength from 0 to 0.5 mol L⁻¹. Adsorption isotherms of acid red on sepiolite were determined and correlated with common isotherm equations such as Langmuir and Freundlich models. It was found that the Langmuir model appears to fit the isotherm data better than the Freundlich model. The physical properties of this adsorbent were consistent with the parameters obtained from the isotherm equations. Approximately, 21.49% weight loss was observed. The surface area value of sepiolite was 342 m² g⁻¹ at 105 °C, and it increased to 357 m² g⁻¹ at 200 °C. Further increase in temperature caused channel plugging and crystal structure deformation, as a result the surface area values showed a decrease with temperature. The data obtained from adsorption isotherms at different temperatures have been used to calculate some thermodynamic quantities such as the Gibbs energy, heat and entropy of adsorption. The thermodynamic data indicate that acid red 57 adsorption onto sepiolite is characterized by physical adsorption. The dimensionless separation factor (R_L) have shown that sepiolite can be used for removal of acid red 57 from aqueous solutions. The sorption capacity of the sepiolite is comparable to the other available adsorbents, and it is quite cheaper.

Keywords: Adsorption, Dye, Clay mineral, Sepiolite, Langmuir model

Nur, H., Manan, A.F.N.A., Wei, L.K., Muhid, M.N.M. and Hamdan, H. (2005), Simultaneous adsorption of a mixture of paraquat and dye by NaY zeolite covered with alkylsilane. Journal of Hazardous Materials, 117 (1), 35-40.

Full Text: J\J Haz Mat117, 35.pdf

Abstract: The surfaces of NaY zeolite particles were modified by the alkylsilylation of n-octadecyltrichlorosilane (OTS). Two kinds of modified NaY zeolites were prepared; one with its external surface partially and the other fully covered with alkylsilyl groups. Since the size of OTS is bigger than the pore diameter of NaY, it is attached on the external surface, leaving the internal pore accessible to adsorbate molecules. As a result of alkylsilylation, the adsorption properties of these sorbents were improved. The adsorption properties of these materials were tested by their reaction in a mixture of paraquat and blue dye. The results demonstrate that the alkysilylated NaY materials are capable of simultaneous adsorption of paraquat and blue dye. Paraquat was selectively adsorbed into the internal pore of the zeolite whereas the dye on the externally attached alkylsilyl groups of the sorbent; displaying the unique bimodal amphiphilic character of the alkylsilylated NaY zeolites.

Keywords: Paraquat, Blue Dye, Alkylsilylation, NaY Zeolite

Saeed, A. Iqbal, M. and Akhtar, M.W. (2005), Removal and recovery of Lead(II) from single and multimetal (Cd, Cu, Ni, Zn) solutions by crop milling waste (black gram husk). Journal of Hazardous Materials, 117 (1), 65-73.

Full Text: J\J Haz Mat117, 65.pdf

Abstract: The study reports removal of heavy metals when present singly or in binary and ternary systems by the milling agrowaste of Cicer arientinum (chickpea var. black gram) as the biosorbent. The biosorbent removed heavy metal ions efficiently from aqueous solutions with the selectivity order of Pb > Cd > Zn > Cu > Ni. The biosorption of metal ions by black gram husk (BGH) increased as the initial metal concentration increased. Biosorption equilibrium was established within 30 min, which was well described by the Langmuir and Freundlich adsorption isotherms. The maximum amount of heavy metals (q_max) adsorbed at equilibrium was 49.97, 39.99, 33.81, 25.73 and 19.56 mg/g BGH biomass for Pb, Cd, Zn, Cu and Ni, respectively. The biosorption capacities were found to be pH dependent and the maximum adsorption occurred at the solution pH 5. Efficiency of the biosorbent to remove Pb from binary and ternary solutions with Cd, Cu, Ni and Zn was the same level as it was when present singly. The presence of Pb in the binary and ternary solutions also did not significantly affect the sorption of other metals. Breakthrough curves for continuous removal of Pb from single, binary and ternary metal solutions are reported for inlet-effluent equilibrium. Complete desorption of Pb and other metals in single and multimetal solutions was achieved with 0.1 M HCl in both shake flask and fixed bed column studies. This is the first report of removal of the highly toxic Pb, Cd, and other heavy metals in binary and ternary systems based on the biosorption by an agrowaste. The potential of application for the treatment of solutions containing these heavy metals in multimetal solutions is indicated.

Keywords: Heavy Metals Removal, Wastewater, Black Gram Husk, Biosorbent, Lead

Marinović, V., Ristić, M. and Dostanić, M. (2005), Dynamic adsorption of trinitrotoluene on granular activated carbon. Journal of Hazardous Materials,