Combining zero-valent iron nanoparticles with microwave energy to treat chlorobenzene

In this research, MW energy is combined with nanoscale zero-valent iron (ZVI or Fe0) particles suspended in aqueous chlorobenzene (CB) solution for enhancing the CB decomposition. When MW energy is applied at 250 W for 300 s to irradiate 100 mg/L of CB solution containing 1 g ZVI particles, the CB activation energy is decreased by 8.6 kJ/mol (21.9–13.3 kJ/mol) so that the CB removal efficiency is enhanced 4.6 times (82.8% vs. 18.1%). The reductive dechlorination reaction occurs at the surface of zero-valent iron particles; the organic substance in the bulk of the solution diffuses to the iron particle surface to contact the iron particle for the reductive dechlorination reaction to occur. When MW radiation penetrates the solution to reach the surface of suspended Fe0 particles, the radiation accelerates the iron oxidization, and increases the surface activity site thus enhancing the CB decomposition rate. Hence the MW-induced zero-valent iron can reduce the CB activation energy that contributes to the enhanced rate of CB removal.