This study investigated the effect of nonionic and cationic surfactants on the dechlorination kinetics and products distribution of a series of chlorobenzenes (CBs) by Cu/Fe particles. Results showed that the reduction rates of CBs increased with the increase in chlorination. The rate constants were closely correlated to their lowest unoccupied molecular orbital (LUMO) energies and logarithmic octanol-water partition coefficients (Log K-ow). Lower LUMO energy and larger Log Kow value led to higher rate constant. The presence of nonionic surfactant of Triton X-100 (TX-100) greatly increased the dechlorination of CBs with higher hydrophobicity (>4Cl), and inhibited the dechlorination with lower hydrophobicity (<4Cl). The presence of cationic surfactant of myristylpyridinium bromide (MPB) showed similar but less significant effect on CBs reduction compared with TX-100. The hydrophobic-hydrophilic variation in the near surface of Cu/Fe in the presence of different surfactants was responsible for the different effect. Regarding the dechlorination productions distribution, the presence of TX-100 led to significant accumulation of CBs with one and two chlorine less, while the presence of MPB resulted in the accumulation of CBs with only one chlorine less. (C) 2010 Elsevier B.V. All rights reserved.