Batch and fixed-bed assessment of sulphate removal by the weak base ion exchange resin Amberlyst A21 (original) (raw)
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Sulfate uptake by a polyacrylic anion exchange resin (Amberlite IRA458) was studied in batch and fixed-bed experiments. Loading increases with acidity and at pH 2.0, the sulfate loading kinetics is pseudo first order whereas the sorption isotherm can be described by both the Langmuir and Freundlich models. Fixed bed experiments produced high sulfate loading (70 mg SO₄²⁻/L-resin) at pH 2.0 where HSO₄⁻ concentration is relevant. Column breakthrough data were fitted to Bohart-Adams, Thomas, Yoon and Nelson and Dose-Response models and all equations could predict the experimental results.
Study of sulphate ions removal from acidic waters using ion exchange resin
Selected Scientific Papers - Journal of Civil Engineering, 2018
Acid Mine Drainage (AMD) is the most common pollution related to mining. It consists of an aqueous solution containing high metals and sulphate concentration, which impact surface and groundwater and lead to serious environmental problems. Low pH and high concentrations of heavy metals and sulphates are limiting for many various treatment technologies in these acidic waters. Ion - exchange is a very powerful technology where one or more undesirable contaminants are removed from water by exchange with another non-objectionable or less objectionable substance. Many of materials for the ion - exchange treatment is available in a variety forms and have widely differing chemical and physical properties. The paper deals with study of ion - exchange process under static and dynamic conditions for sulphate removal from acidic waters using ion - exchange resin with the aim to apply the results for treatment of acid mine drainage. Two types of experiments were performed under static and dynam...
Journal of environmental management, 2014
Acid mine drainage is a natural process occurring when sulfide minerals such as pyrite are exposed to water and oxygen. The bacterially catalyzed oxidation of pyrite is particularly common in coal mining operations and usually results in a low-pH water polluted with toxic metals and sulfate. Although high sulfate concentrations can be reduced by gypsum precipitation, removing lower concentrations (below 1200 mg/L) remains a challenge. Therefore, this work sought to investigate the application of ion exchange resins for sulfate sorption. The macroporous type 1 strong base IX resin Purolite A500 was selected for bath and fixed-bed sorption experiments using synthetic sulfate solutions. Equilibrium experiments showed that sulfate loading on the resin can be described by the Langmuir isotherm with a maximum uptake of 59 mg mL-resin(-1). The enthalpy of sorption was determined as +2.83 kJ mol(-1), implying an endothermic physisorption process that occurred with decreasing entropy (-15.5 ...
Sorption studies on ion exchange resins. 1. Sorption of strong acids on weak base resins
Industrial & Engineering Chemistry Research, 1992
Sorption equilibria and batch dynamics of weak acids (formic acid and monochloroacetic acid) on weak base ion exchange resins, in free base form, are studied. The reversible sorption model based on double layer theory, developed in part 1 of these studies, is extended to take into account undissociated acid species. The model fits the experimental dynamics satisfactorily over the entire range of resin conversion. Values of effective ionic pore diffusion coefficient, regressed from the observed experimental dynamics, have been satisfactorily correlated on the basis of the model. These studies reveal that the contributions of both the ionic and the undissociated molecular species are important in determining the total diffusive flux of the acid in the pores of the resin. .. Cliffs, Nj, 1978. Process Technol. 1981.2, 1. I Wadekar, V. V.; Sharma, M. M. Dissociation extraction. J. Sep.
Sorption studies on ion exchange resins. 2. Sorption of weak acids on weak base resins
Industrial & Engineering Chemistry Research, 1992
Sorption equilibria and batch dynamics of weak acids (formic acid and monochloroacetic acid) on weak base ion exchange resins, in free base form, are studied. The reversible sorption model based on double layer theory, developed in part 1 of these studies, is extended to take into account undissociated acid species. The model fits the experimental dynamics satisfactorily over the entire range of resin conversion. Values of effective ionic pore diffusion coefficient, regressed from the observed experimental dynamics, have been satisfactorily correlated on the basis of the model. These studies reveal that the contributions of both the ionic and the undissociated molecular species are important in determining the total diffusive flux of the acid in the pores of the resin. .. Cliffs, Nj, 1978. Process Technol. 1981.2, 1. I Wadekar, V. V.; Sharma, M. M. Dissociation extraction. J. Sep.
Industrial & Engineering Chemistry Research, 1999
Experimental data for the distribution of water-ethanol mixtures between a solid phase and a liquid phase at 298 K are reported. The solid phases studied were gel-type sulfonated poly-(styrene-co-divinylbenzene) resins of different degrees of cross-linking (4-8% DVB) and carrying different counterions (Na + , Ca 2+ , and La 3+ ). The shear moduli of the resin beads were also measured to characterize their elastic properties. All resins absorb water selectively, and the selectivity increases with increasing cross-link density. The low selectivity of the less densely cross-linked resins is shown to be mainly due to the mutual interaction of the solvents in the resin phase resulting in a pronounced maximum in the ethanol sorption isotherms. The influence of the counterion on the selectivity is more complex. At high water contents, the water selectivity of the Na + resin is higher than that of the Ca 2+ and La 3+ resins, whereas the selectivities are approximately equal at low water contents. The elastic properties of the resin beads remain unchanged from pure water to water mole fractions of around 0.4, where a sharp rise in the shear modulus occurs. The data are analyzed by means of a model based on the UNIQUAC equation and the affine network theory of elasticity. The effect of cross-link density on the selectivity and solvent content of the resins can be explained satisfactorily with the model. However, the calculated and experimental sorption isotherms for the La 3+ resins deviate appreciably at low external water contents. The discrepancies are discussed on the basis of the elastic properties of the resins and the specific solvation interactions.
Sulphate Removal from Flotation Process Water Using Ion-Exchange Resin Column System
Minerals
Water chemistry is one of the most important parameters affecting flotation performance. Various types of ions can dissolve and accumulate in process water depending on ore mineralogy, reagent scheme, grinding medium and chemistry of mine site water. Sulfur-based ions (sulfate, thiosulfate, polythionate) are generally observed in flotation of sulfide ores. High concentrations of these ions may reduce efficiency of the flotation process, causing scale problems. Removal of these ions from process water often requires complex water treatment plants with high capital and operating costs. In this study, partial cleaning of water was investigated as an alternative approach for decreasing high sulphate concentrations of 3000–3800 mg/L down to 1000–1500 mg/L, an acceptable concentration for most sulfide ore flotation plants, by using an ion-exchange resin. For this purpose, detailed adsorption tests were performed using a laboratory-scale column system to determine the most suitable type of...
Removal of Phosphate by Ion Exchange Resin: Kinetic and Thermodynamic Study
Rasayan Journal of Chemistry
The removal of phosphate ions by a weakly basic anion exchanger Amberlite IRA-67 resin was investigated. Equilibrium data were best described by Freundlich isotherm and second-order kinetic equation. Thermodynamic parameters reveal that adsorption is spontaneous and a heat releasing process.
Journal of Water Process Engineering, 2017
Analcime and commercial zeolite were employed as a precursor for preparing sorbent material for SO4 2removal over barium modification. Three sorbents were prepared: barium-modified analcime (ANA-Na-Ba), barium-modified acid-washed analcime (ANA-Ac-Na-Ba) and bariummodified zeolite (ZSM5-Na-Ba). Of the prepared materials, ANA-Ac-Na-Ba was the most efficient sorbent material for SO4 2removal, with a maximum sorption uptake of 13.7 mg g-1 at room temperature. Batch sorption experiments were performed to evaluate the effect of initial pH, initial SO4 2concentration, sorbent dosage, temperature and contact time of sorption. Several isotherms were applied to describe the experimental results and Bi-Langmuir was found to provide the best correlation for adsorption of SO4 2on ANA-Ac-Na-Ba. Kinetic studies were applied for the most effective sorbent material, ANA-Ac-Na-Ba, and the results showed that the sorption process follows pseudo-second-order kinetics.
2010
The removal of sulphate ions constitutes one of the main challenges in the mining, metallurgical and chemical industries, among others. Sulphate removal from aqueous streams is by far one of the most difficult and onerous tasks in these industries, and most existing processes are inefficient and costly. This work presents a method to remove sulphate ions in an acidic medium based on co-precipitation with aluminum salts, namely AlCl 3 and a polyaluminum salt (PAC), followed by filtration. Herein, the different Al species react differently with sulphate, forming soluble and insoluble complexes, the latter of which causes insolubility and allows for the removal. The reaction kinetics depend on the activity of the socalled Al b species (which are classified as polymeric) and was proved here by different techniques. Better results were obtained with the inorganic salt AlCl 3 , when compared to PAC, probably because of the higher activity of the Al species. Co-precipitation of sulphate depends highly on the pH (which is optimal at 4.5), the mass ratio between reagents and sulphate ions (which is optimal at 7:1) and time (10 min). Finally, it was concluded that the technique proposed here has good potential for the treatment of sulphate-bearing effluents, including acid mining drainage (AMD).