This work investigated the simultaneous conversion of organic dyes (methyl orange (MO), rhodamine B (Rh B)), and hexavalent chromium (Cr(VI)) by using the SnO2/rGO (SnG) photocatalyst. The effects of the mixture ratios of organic dye and hexavalent chromium (Cr(VI)), and pH value of the mixture to the simultaneous degradation and reduction process were investigated systematically. The existing experimental results proved that there was a synergistic effect between the photocatalytic degradation of the given organic dyes (MO and Rh B) and reduction of Cr(VI). And also, the low pH value is able to significantly improve the removal rate of organic dyes and Cr(VI) in the mixture systems. At the same time, the possible mechanism of the effect of the different organic dyes and pH value on the photocatalytic reduction efficiency of Cr(VI) was briefly discussed. (C) 2015 Elsevier B.V. All rights reserved.