title: Highly efficient detoxification of Cr(VI) by chitosan-Fe(III) complex: process and mechanism studies.
abstract: Metal-biopolymer complexes has recently gained significant attention as an effective adsorbent used for the removal of Cr(VI) from water. Unfortunately, despite increasing research efforts in the field of removal efficiency, whether this kind of complex can reduce Cr(VI) to less-toxic Cr(III) and what are the mechanisms of detoxification processes are still unknown. In this study, despite the highly adsorption efficiency (maximum adsorption capacity of 173.1 mg/g in 10 min), the significant improvement of Cr(VI) reduction by chitosan-Fe(III) complex compared with normal crosslinked chitoan has been demonstrated. In addition, the structure of chitosan-Fe(III) complex and its functional groups concerned with Cr(VI) detoxification have been characterized by the powerful spectroscopic techniques X-ray absorption fine structure (XAFS) and X-ray photoelectron spectroscopy (XPS). The XPS spectra indicated that the primary alcoholic function on C-6 served as an electron donor during Cr(VI) reduction and was oxidized to a carbonyl group. The X-ray adsorption near edge spectra (XANES) of the Cr(VI)-treated chitosan-Fe(III) complex revealed the similar geometrical arrangement of Cr species as that in Cr(III)-bound chitosan-Fe(III). Overall, a possible process and mechanism for highly efficient detoxification of Cr(VI) by chitosan-Fe(III) complex has been elucidate.
authors.affiliation: MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Chensi
authors.initials: C
authors.lastname: Shen
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Shaoshuai
authors.initials: S
authors.lastname: Wu
authors.forename: Yuezhong
authors.initials: Y
authors.lastname: Wen
authors.forename: Lina
authors.initials: L
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Jiang
authors.forename: Meichao
authors.initials: M
authors.lastname: Li
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D048271:Chitosan