Rapid dechlorination of chlorophenols in aqueous solution by [Ni|Cu] microcell

The [Ni vertical bar Cu] microcell was prepared by mixing the Ni-0 and Cu-0 particles. The composition and crystal form were characterized by X-ray diffraction (XRD) and scanning electron microscope. The results evidenced the zero-valence metals Ni and Cu were exposed on the surface of particles mixture. The [Ni vertical bar Cu] microcell was employed to decompose chlorophenols in aqueous solution by reductive dechlorination. The dechlorination rates of chlorophenols by [Ni vertical bar Cu] were >10 times faster than those by [Fe vertical bar Cu], [Zn vertical bar Cu], [Sn vertical bar Cu], and [Fe vertical bar Ni] mixtures under the same conditions. [Ni vertical bar Cu] is different from other zero valent metals (ZVMs) in that it performed the best at neutral pH. The main products of chlorophenol dechlorination were cyclohexanol and cyclohexa none. The reduction kinetics was between pseudo zero-order and first-order, depending on the pH, concentration, and temperature. These results, combined with electrochemical analysis, suggested that Ni-0 acted as a reductant and catalyst in dechlorination reaction. The H* corridor mechanism from Ni-0 to Cu-0 was also proposed based on hydrogen spillover. The inhibition on the release of Ni2+ by adding natural organic matters and adjusting pH was investigated. (C) 2012 Elsevier B.V. All rights reserved.