Synthesis, characterization and re-activation of a Fe0/Ti system for the reduction of aqueous Cr(VI)

The conventionally employed zero-valent iron (Fe-0) particles suffer a formation of surface oxides to lower their activity prior to use. During their using process for contaminant remediation, such oxide formation is also encountered, while the cumbersome handling of particles impedes the Fe-0 recovery. To conquer the drawbacks, a Fe-0 film was synthesized by electrodepositing ferrous ion cathodically on titanium (Ti) substrate to form a new Fe-0/Ti system. X-ray diffraction (XRD) revealed that the freshly electrodeposited (FED) Fe-0 film was free of oxides, which was attributed to the particularity of electrodeposition procedure. Reduction results of 10.0mg/L chromium [Cr(VI)] indicated that the FED Fe-0 film had higher activity than the oxide-covered counterpart. Further analysis of the pH-dependent Cr(VI) reduction reaction indicated that the Fe-0/Ti system kept its activity and could be reused for further Cr(VI) reduction at pH 3.0 and 4.0, while it was inactivated at pH 5.0 and 7.0. Due to the easy handling of Fe-0/Ti system, the inactivated Fe-0 was recovered significantly through a cathodic reduction. (C) 2007 Elsevier B.V. All rights reserved.