Mechanisms of Cr(III) and Cr(VI) removal from aqueous solutions by sugar beet pulp

The removal of three- and hexavalent chromium from aqueous solutions using sugar beet pulp as biosorbent substratewas performed. The kinetics of Cr(III) and Cr(VI) removal were studied at 20.0 +/- 0.5 degrees C and under various experimental conditions. The Cr(III) ions were adsorbed onto the biosorbent by ion-exchange mechanism with Ca2+ cations. The influence of solution pH was found to greatly affect the adsorption efficiency of Cr(VI). Cr(VI) removal was largely involved in a reduction mechanism with the appearance of Cr(III) ions in the solution.