Catalytic Dechlorination of Para-Nitrochlorobenzne in Wastewater through a Nanoscale Nickel-Iron Bimetallic Catalyst

In this research, nickel/iron (Ni/Fe) bimetallic nanoparticles were used for the dechlorination of para-nitrochlorobenzene (p-NCB) which could be identified in contaminated soil and wastewater. In the reaction, Ni acted as a collector of hydrogen and the Fe was corroded for producing hydrogen gas. p-NCB was rapidly adsorbed onto the surface of the nanoparticles. Then, p-NCB was degraded to p-CAN and reduced to aniline, or dechlorinated directly to aniline. It was indicated that Ni loading ratio, Ni/Fe mass ratio, and reaction temperature could greatly affect the dechlorination process of p-NCB. Under similar conditions, when 6 g/L of nanoscale Ni/Fe was used, the dechlorination efficiencies reached 25.9 and 100% under 0.5 and 2.0% of Ni/Fe mass ratios, respectively. Thus, a negative linear correlation between the reaction rate and the initial concentration of p-NCB (within a range of 20 to 80 mg/l) could be observed. The reaction activation energy of 94.6 kJ/mol was obtained within the temperature range of 15 to 35 °C.