title: Combination of electroreduction with biosorption for enhancement for removal of hexavalent chromium.
abstract: Hexavalent chromium is one of the most toxic heavy metals in aqueous solutions. It has been well documented that the brown seaweed can be used as a promising biosorbent for the sequestration of this heavy metal from wastewater. However, the uptake of Cr(VI) is reportedly a rather slower process; the sorption equilibrium can only be established after a few days, much slower than a few hours for the trivalent chromium ion. In this study, we developed a novel technology of electrochemically assisted biosorption (ECAB) system for the enhancement of the treatment efficiency. It was found through our study that the removal efficiencies of Cr(VI) and total chromium were greatly enhanced by 48.1% and 51.3%, respectively, with the application of -1.0 V in the ECAB system. The conversion of Cr(III) due to the electroreduction of Cr(VI) and the higher pH due to the cathodic H(2) evolution created a favorable condition for the uptake of chromium onto the modified seaweed (MSW). The reduction and adsorption of Cr(VI) by MSW was proved to play a minor role in the removal. Both direct electroreduction and indirect electroreduction by atomic H* contributed to the reduction of Cr(VI).
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Yining
authors.initials: Y
authors.lastname: Hou
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liu
authors.forename: Xu
authors.initials: X
authors.lastname: Zhao
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
authors.forename: J Paul
authors.initials: JP
authors.lastname: Chen
mesh_terms: D002857:Chromium / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D010084:Oxidation-Reduction; D044647:Sargassum / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D002857:Chromium; C074702:chromium hexavalent ion