Adsorptive removal of hexavalent chromium using sawdust: Enhancement of biosorption and bioreduction

Simultaneous biosorption and bioreduction experienced by Cr(VI) species were initially validated by mixing 500 mu M of Cr(VI) with 0.20 g of sawdust biosorbent. Accordingly, a complete disappearance of Cr(VI) species with emergence of 25% of Cr(III) ions was recorded; evidencing that both processes transpired simultaneously. An increase in the initial Cr(VI) concentration to 1500 mu M could further induce more reduced Cr(VI) concentration. The enhancement of Cr(VI) biosorption and bioreduction was found to occur upon increasing the sawdust dosage to 4 g L-1 and decreasing the solution pH to 2. However, the presence of a Zn(II) co-pollutant at 2500 mu M had deteriorated the removal of Cr(VI) species.