Chromic acid removal by anion exchange

Abstract

The kinetics of dilute chromic acid removal by anion exchange was studied using a batch system. Rate model formulated for total Cr(VI) removal based on film diffusion control was applied. This rate model was shown to adequately fit the experimental rate data. In addition, column experimental runs were performed by using 20-50 mesh anion resin with feed solution containing 0.2 g/L CrO3. The bed heights of 15, 25 and 35 cm and flow rates ranging from 1.02 cm/s to 2.38 cm/s were employed in the experiments. Linear driving force rate expression based on film diffusion rate control was incorporated in the model equations for simulation of column performance. The kinetic parameter and equilibrium relation in the rate equation were obtained independently either by separate experiments or from data available in the literature. Satisfactory agreements between experimental and calculated breakthrough curves were obtained.