Coexistence of organic compounds and heavy metals in industrial wastewater effluent is a serious environmental problem. In this study, pyrite was successfully employed as a photocatalyst for the simultaneous removal of malachite green (MG) and Cr(VI). The removal efficiency of MG and Cr(VI) were 96.7% and 53.1%, respectively after 120 min. The presence of Cr(VI) significantly promoted MG degradation, and the reduction ratio of Cr(VI) was significantly accelerated in the presence of MG, demonstrating an obvious synergism between MG degradation and Cr(VI) reduction. The presence of Cr(VI) did not change the kinetic order of MG degradation. The presence of dissolved oxygen could enhance the degradation ratio of MG, but decrease the reduction ratio of Cr(VI) despite the fact that both Cr(VI) and 02 are competitive electron acceptors. Photocatalytic efficiency of the coexistence system was superior to that of the single system when the catalyst was continuously used for 5 times. A synergistic mechanism involving reactive oxygen species produced from photo-Fenton-like process for the MG degradation, whereas the Cr(VI) reduction mainly by direct electrons of pyrite, not reaction of O-2(center dot-) with Cr(VI) was proposed. This is the first report on the application of pyrite particles as a photocatalyst for the simultaneous removal of organic compounds and heavy metals. (C) 2015 Elsevier B.V. All rights reserved.