Enhanced photocatalytic degradation of ofloxacin by Sm2Ti2O7 supported on quartz sand

Abstract

Sm2Ti2O7 (STO) was synthesized on quartz sand (QS) to inhibit STO particle aggregation and to promote the activity of STO. The growth of STO crystals was reduced after loading STO onto the surface of QS. The bandgap energies of 20%STO-QS, 50%STO-QS, 80%STO-QS and pure STO were calculated to be 3.67, 3.64, 3.62 and 3.41 eV, respectively. 50%STO-QS had the largest surface area and the largest pore volume, since the supported STO layer was more porous than pure STO. The lifetimes of the holes and electrons produced by pure STO were much shorter than those produced by χSTO-QS composites. The activity of χSTO-QS composites increased with increasing STO content, and the strongest photocatalytic activity was obtained for 50%STO-QS. The reaction rate constants of ofloxacin degradation for pure STO, 20%STO-QS and 50%STO-QS were calculated to be 0.00977, 0.0148 and 0.0220 min−1, respectively. The ofloxacin degradation efficiency for the first reaction cycle conducted with 50%STO-QS was 47.8%, while the efficiency was 35.6% for the fifth degradation process.