Use of activated carbon as a reactive support to produce highly active-regenerable Fe-based reduction system for environmental remediation

摘要

Composites based on iron supported on high surface area activated carbon were prepared and characterized with ~(57)Fe Moessbauer spectroscopy, X-ray diffraction, saturation magnetization measurements and temperature-programmed reduction. Upon thermal treatment, the supported iron oxides react with carbon to yield reduced chemical species, i.e. Fe_3O_4 and Fe(0). This so produced composite was found to be highly efficient in two environmental applications: (i) degradation of textile dye and (ii) reduction of Cr(VI) in aqueous medium. Sequential reuses evidenced a progressive chemical deactivation of the composites due to a corresponding oxidation of the reactive species. Even after being virtually deactivated, the initial chemical reducing ability of the composites can be regenerated by heating at 800 ℃ under N_2 atmosphere, and then reused for several consecutive times.