Abstract
In this work, mesoporous Gd2O3-TiO2 nanocomposites synthetized by a sol-gel with vary Gd(2)O(3)concentration were investigated for photo-destruction of imazapyr herbicide waste. Textural, structural and surface properties of the synthetized nanocomposites are verified by N(2)physisorption, X-ray diffractometry, HRTEM and various spectroscopic techniques (FTIR, DRS UV-Vis, Raman, PL and XPS). HRTEM micrographs of the calcined Gd2O3-TiO(2)revealed the existence of a mesoporous matrix consisting of homogeneously distributed TiO(2)nanoparticles (NPs, 12 nm) which are decorated with Ga(2)O(3)nanoparticles. It was found a reverse correlation between the amount of Gd(2)O(3)concentration and the TiO(2)nanoparticle size: the formation of smaller TiO(2)nanoparticles was favored by the use of high Gd(2)O(3)concentration. The photocatalytic efficiency of the synthetized Gd2O3-TiO2 nanocomposites was appraised in the photo-destruction of imazapyr herbicide below visible-light irradiation. The best herbicide destruction was achieved using 3%Gd2O3-TiO2 photocatalyst and degraded the imazapyr herbicide 20.5 and 8.2 times faster than a commercial P25 and non-promoted TiO2, respectively, indicating that modification of TiO(2)with Gd(2)O(3)led to a significant improvement of photocatalyst efficiency. This was explained as due to a lessening of the apparent optical bandgap and the formation of a large amount of surface defect states favoring the separation between electrons and holes. Besides its high efficiency, the 3%Gd2O3-TiO(2)photocatalyst demonstrated to be recyclable and stable in the visible-light-driven photocatalytic destruction of imazapyr herbicide.