The photocatalytic degradation of 4-methylbenzoic acid (MBA) and 2-chloro-5-nitro benzoic acid (CNBA) as aqueous solution mixture was studied using ZnO-SnO2/nano-clinoptilolite under UV irradiation. The clinoptilolite nano-particles (CNP) were obtained via ball-mill method and ion exchanged in Zn2+-Sn4+ aqueous solutions with different concentrations. The ion exchanged samples (Zn(II)-Sn(IV)/CNP) were calcined at 450 degrees C for 12 h to obtain ZnO-SnO2/CNP catalysts. XRD, DRS, FT-IR and TEM techniques were applied for characterization of samples. The experimental parameters which influenced degradation process were optimized and the optimum values were obtained as: 1 g L-1 of the photocatalyst, pH 5 and 5 mg L-1 of MBA and CNBA in the mixture. The degradation/ mineralization extents were confirmed by COD and HPLC. (C) 2015 Elsevier B.V. All rights reserved.