Fe/Cu bimetallic catalysis for reductive degradation of nitrobenzene under oxic conditions

Iron/copper (Fe/Cu) bimetallic particles have been proposed as a viable technology for reduction of nitrobenzene from wastewater, however, little data is currently available on its applicability in the presence of the dissolved oxygen (DO). In this study, the prepared Fe/Cu bimetallic particles with different theoretical copper mass loadings were characterized by SEM, EDS, BET and XRD. Also, the effect of theoretical Cu mass loading and other operating parameters (such as initial pH, initial nitrobenzene concentration, the Fe/Cu bimetallic dosage and the reaction temperature) under oxic conditions (DO > 6.5 mg/L) were investigated, respectively. The results suggest that Cu planted on the iron surface could enhance the reduction, while the dense Cu layer could seriously decrease its reactivity. Under oxic conditions, neutral surroundings could enhance the reduction more obviously. This phenomenon indicated that DO could enhance the direct reduction on the catalytic activity site of iron surface. The result of the reduction efficiency of nitrobenzene under oxidizing atmosphere indicated that besides the reduction, the sorption onto the iron hydroxides generated from Fe0 during treatment and the existence of Fenton-like degradation was also responsible for the removal of nitrobenzene. The data of the chemical oxygen demand (COD) and total organic carbon (TOC) indicated that DO could facilitate the removal of organics. Thus, Fe/Cu bimetallic particles can reach high efficiency for treatment of toxic nitrobenzene-contained wastewater under oxic conditions.