Removal of Antibiotic Florfenicol by Sulfide-Modified Nanoscale Zero-Valent Iron

摘要

Florfenicol (FF, C_(12)H_(14)Cl_2FNO_4S), an emerging halogenated organic contaminant of concern was effectively degraded in water by sulfidized nanoscale zerovalent iron (S-nZVI). Sulfidized nZVI (62.5 m~2 g~(-1)) that was prepared using a one-step method resulted in small Fe~0/Fe-sulfide particles that were more stable against aggregation than unsulfidized nZVI (10.2 m`2 g~(-1)). No obvious removal of FF was observed by unsulfidized nZVI. S-nZVI degraded FF, having a surface area normalized reaction rate constant of 3.1 × 10(-4) L m~(-2) min~(-1). The effects of the S/Fe molar ratio, initial FF concentration, initial pH, temperature, and water composition on the removal of FF by S-nZVI, and on the formation of reaction products, were systematically investigated. Both dechlorination and defluorination were observed, resulting in four degradation products (C_(12)H_(15)ClFNO_4S, C_(12)H_(16)FNO_4S, C_(12)H_(17)NO_4S, and C_(12)H_(17)NO_5S). High removal efficiencies of FF by S-nZVI were achieved in groundwater, river water, seawater, and wastewater. The reactivity of S-nZVI was relatively unaffected by the presence of both dissolved ions and organic matter in the waters tested.