Clinoptilolite modified with TiO2 for simultaneous elimination of two herbicides; 2,4-D and MCPA by UV and sunlight-assisted photocatalytic degradation

Abstract In this work, a photocatalyst prepared by titanium dioxide doped on clinoptilolite nanoparticles was used for simultaneous degradation of 2,4-dichlorophenoxyacetic acid (2,4-D), and 2-methyl-4-chlorophenoxyacetic acid (MCPA) mixture under ultraviolet and sunlight irradiations. The results indicated that by immobilization of titanium dioxide on clinoptilolite surface, the efficiency of photocatalyst by sunlight irradiation was significantly increased. This was in agreements with the results obtained by diffuse reflectance spectroscopy and photoluminescence analysis which respectively indicated that photocatalyst band gap shifted to the visible region and recombination of electron-hole was significantly reduced. To optimize the degradation efficiency, the effects of various experimental variables and different scavengers were studied. The degradation efficiency was estimated by determination of total organic carbon, and the degradation products were detected by HPLC technique.