Synthesis of anatase nanopowders by sol-gel method and photocatalytic degradation of the pure active substance and commercial product of herbicide clomazone

Abstract

TiO2 nanopowders were produced by sol-gel technique using TiCl4 as the starting material. For the preparation of anatase crystalline, this aqueous solution was the mixed with 0.05 M and 0.07 M (NH4)2SO4 solution in a temperature-controlled bath. PH values of the solutions were 7, 8 and 9, respectively. Structural, morphological and surface properties of synthesized TiO2 nanopowders were investigated by XRD, SEM, and BET measurements. The crystallite sizes determined by XRD measurements had range about 12 nm, and this was confirmed by SEM. The photocatalytic degradation of the pure active substance and commercial product (GAMIT 4-EC) of herbicide clomazone (0.05 mM) in aqueous suspensions of synthesized and commercial (Degussa P25) TiO2 were examined under UV radiation. In all experiments the concentration of the catalyst was 0.50 mg mL-1. BET measurements revealed that all synthesized catalyst had mesoporous structure, except the sample synthesized with 0.07 M (NH4)2SO4 and at pH of solution 9 that had small amount of micropores. This sample had the best photocatalytic properties, even better than commercial Degussa P25, and the reason of that is rather the biggest porosity than the combination of micro- and mesoporosity.