Cuprous oxide is firstly created on acidized sepiolite (AS) by a simple deposition method for photocatalytic degradation of the red water produced from 2,4,6-trinitrotoluene (TNT) manufacturing. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), ultraviolet-visible diffuse reflection absorptive spectroscopy (UV-vis/DRS), and Fourier transform infrared (FT-IR) spectroscopy are used to characterize the photocatalyst composites. Gas chromatography/mass spectrometry (GC/MS) is employed to determine the organic constituents in the red water. The results show that the cuprous oxide particles can be immobilized on the surface of the AS fibers and the structure of the AS is altered when cuprous oxide interacts with AS via chemical reactions besides physical adsorption. The AS improves the optical properties of cuprous oxide and red-shifts the band gap thereby enhancing the utilization of visible light. The Cu2O/AS composites demonstrate excellent photocatalytic performance in the degradation of red water. 87.0% of red water can be photocatalytically degraded by Cu2O/AS after illumined for 5 h and a majority of organic components of red water except 1,3,5-trinitrobenzene were degraded according to GC-MS analysis. (C) 2011 Elsevier B.V. All rights reserved.