Due to the different sources of charcoals, there are significant differences in their properties. In order to study the catalytic effect of different charcoals to nitrobenzene (NB), we selected nine charcoal-sources to prepare nine charcoals with different properties. The experiments showed that NB could be rapidly reduced by sulfides in the presence of all charcoals. The surface area normalized reduction rate constants of NB increased with H/C and (O+N)/C ratio of charcoals increasing. The difference of catalytic effect for nine charcoals was mainly due to their different species and content of surface functional groups and original organic matter. Based on the theoretical calculation and experimental results, the reaction mechanism of NB catalyzed by charcoal in sulfides solution was analyzed. Some active surface functional groups and original organic matter of charcoals were regarded as the active sites and played an important role in catalyzing the reduction of NB by accelerating the transfer of electrons from sulfides to NB.
