Hexavalent chromium reduction and chromium biosorption by Prunus serotina bark

The capacity of Prunus serotina bark to remove hexavalent chromium [Cr(VI)] and total chromium from acidic aqueous solutions was investigated. P. serotina bark exhibited high Cr(VI) removal capacity (93.61 mg g^-1) as well as total chromium removal capacity (69.93 mg g^-1). The mechanism of Cr(VI) removal by P. serotina bark implies two simultaneous processes: 1) the reduction of Cr(VI) to Cr(III) in the presence of P. serotina bark in an aqueous acidic solution, and 2) the biosorption of chromium ions. The kinetic model that satisfactorily described the chromium biosorption process from the Cr(VI) solution was the pseudo second-order model. The experimental results suggest that P. serotina bark biosorbed chromium ions predominantly by a chemical sorption phenomenon. The results of this work underline that P. serotina bark may be used as an effective and low-cost biomaterial for the removal of both Cr(VI) and total chromium from polluted water and wastewater.