A reduced graphene oxide (rGO) supported magnetite nanoparticle (nFe(3)O(4)) composite (nFe(3)O(4)/rGO) was synthesized and shown for the first time to be an efficient persulfate activator to generate SO4 for trichloroethylene (TCE) degradation. The degradation efficiency of TCE (0.15 mmol L-1) was 98.6% within 5 min in the presence of 6.94 g L-1 nFe(3)O(4)/rGO with an optimum mass ratio of 1:4 and persulfate concentration of 3.0 mmol L-1. By dispersing nFe(3)O(4) on the rGO surface, nanoparticle agglomeration was prevented and the aggregation of the rGO sheets was disrupted. Both the redox effect coupled in nFe(3)O(4) and the electron transfer by functional groups containing oxygen on the surface of rGO enhanced the SO:I-generation. Given the identified free radical species and the characterization of the nFe304/rGO, a persulfate activation mechanism by nFe(3)O(4)/rGO for the degradation of TCE was interpreted. (C) 2016 Elsevier B.V. All rights reserved.