Gamma irradiated orange peel for Cr(VI) bioreduction

This work presents the γ irradiation (600–3500 kGy) and acid hydrolysis onto orange peel for hexavalent chromium removal. SEM, AFM, TGA-DSC, FTIR, and UV-Vis showed that γ rays enhance degradation and cleavage of orange peel cellulose polymeric chains, increasing the presence of reducing sugars after acid hydrolysis (0.1552 g/g biomass, 3500 kGy). Bioreduction kinetics of Cr(VI) using both solid and solubilized liquid fractions of γ irradiated biomass showed a direct correlation between the applied dose and Cr(VI) removal, reaching 100% of Cr(VI) reduction at pH 2 and 3500 kGy. Cr(VI) reduction is explained as a function of hydrolyzed reducing sugar oxidation.