Modelling of boron removal from solutions using purolite s 108 in a batch reactor
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In this study, ion exchange was applied to artificial boron solutions for boron removal by boron selective Purolite S 108 in a batch reactor. The ion exchange experiments were carried out as a function of initial solution pH, resin-to-solution ratio, stirring speed, temperature, concentration, regeneration, and time. Optimum removal conditions for 400 mg/L initial boron concentration were determined as pH 8.5, temperature 15 degrees C, stirring speed 300 rpm, and resin-to-solution ratio 36 g/500 mL. Maximum boron removal at a concentration of 400 mg/L was obtained as 100%. The highest boron adsorption capacity of the resin was obtained as 9.31 mg/g. The regeneration of the resin was realized by consecutive acid stripping-neutralization-washing treatments. The resin ion exchange capacity values for the first four cycles were found as 8.5, 9.69, 9.37, and 8.45 mg/g, respectively. The obtained kinetic data followed the pseudo second-order model rather than the pseudo first-order kinetic model. Particle diffusion was found as the dominant rate controlling mechanism for boron removal. The activation energy of the complexation reaction between boron and the resin was calculated as 33.5 (kJ/mol). An activation energy of <50 kJ/mol generally indicates a film and particle diffusion controlled process, whereas higher values represent chemical reaction processes. Furthermore, based on the adsorption capacity approach an empirical model was developed.