Preparation and Characterization of Clinoptilolite Impregnated with Titanium Dioxide Nanoparticles to Remove Agricultural Pesticides

Removal of bentazone herbicide through photodegradation process using nanostructured TiO2/Clinoptilolite composite was studied to investigate the potential of clinoptilolite natural support and the effect of the loaded TiO2 content on the process efficiency. For this purpose, TiO2/Clinoptilolite photocatalysts containing different amounts of titania (10, 20, 30, 40 wt.%) were synthesized using a simple and inexpensive wet impregnation method and characterized by XRD, FESEM, EDX, BET, PL, and UV-vis analyses. The characterization results confirmed the successful synthesis of nanocomposite samples and showed that the use of zeolitic support, reducing the recombination rate of electron-hole pairs, improves the dispersion of titania nanoparticles and reduces the accumulation of these particles. The performance results showed that by increasing the TiO2 loading up to 30 wt.%, the removal efficiency of bentazone increases, which is due to the greater number of available active sites. By further increasing the amount of TiO2 loading, the percentage of photocatalytic removal decreases because of the increment in the number of agglomerations on the catalyst surface and the decrement in the adsorption capacity. Also, the kinetic studies show a higher rate of bentazone degradation over the sample containing 30 wt.% of titania and the results follow the first-order kinetic reaction. In order to ensure the efficiency of the selected photocatalyst in the removal of other agricultural pesticides, its efficiency in the photocatalytic removal of paraquat herbicide was also evaluated, which showed good performance. Thus, it can be concluded that the immobilization of the optimal amount of titania on clinoptilolite, in addition to better and easier separation, leads to improved optical and structural properties, and ultimately increased photocatalytic performance.