Abstract
Anion exchanger (Amberlite IRA-420; AMB) has been used in the removal of permanganate ions from potassium permanganate contaminated water. Operational conditions such as permanganate concentration, adsorption time, adsorption temperature, adsorption pH, agitation speed, and finally adsorbent dosage have been investigated, and its impact on the removal process efficiency has been presented. Moreover, the kinetic and equilibrium results obtained for permanganate ions sorption with different initial concentrations onto AMB were analyzed. Kinetic modeling analysis with three different types of kinetic sorption models (pseudo-first-order, pseudo-second-order, and simple Elovich models) was applied to simulate the permanganate ions sorption data. The analysis of the kinetic data indicated that the sorption was a second-order process. An ion-exchange mechanism may have existed in the permanganate ions-sorption process with AMB. The permanganate ions uptake by AMB was quantitatively evaluated with equilibrium sorption isotherms. To describe the isotherms mathematically, the experimental data of the removal equilibrium were correlated with the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) isotherm models, and the applicability of these isotherm equations to the sorption systems was compared by the correlation coefficients. The maximum sorption capacities, determined from the Langmuir isotherm was 20.54 mg/g at 25 degrees C. Moreover, diffusion mechanism of permanganate ions was described by different adsorption diffusion models. The diffusion rate equations inside particulate of Dumwald-Wagner and intraparticle models were used to calculate the diffusion rate. The actual rate-controlling step involved in the permanganate ions sorption process was determined by further analysis of the sorption data applying the kinetic expression given by Boyd.