Highly efficient detoxification of Cr(VI) by chitosan-Fe(III) complex: Process and mechanism studies

► Cr(VI) detoxification by chitosan-Fe(III) complex was in high efficiency. ► XAFS and XPS were used to decipher the mechanism of Cr(VI) detoxification. ► The OH on C-6 of chitosan served as an electron donor during Cr(VI) reduction. ► The geometrical arrangement of adsorbed Cr(VI) was similar as Cr(III). ► Mechanism for detoxification of Cr(VI) by chitosan-Fe(III) complex was elucidated.