Degradation of multiple xanthates using highly efficient visible light-responsive BiOBr-TiO2 composite photocatalysts

Abstract

BiOBr-TiO2 (BT) composite photocatalysts were synthesized by using a two-step method including hydrothermal synthesis and water-bath precipitation. The microstructural characterization analysis proved that high-crystallinity and high-purity binary BT materials were achieved without by-products. TiO2 nanoparticles with a diameter of approximately 15 nm were decorated on multi-layered BiOBr nanosheets. The results showed that BT had highly-improved adsorption capacity and photocatalytic efficiency in comparison to pristine BiOBr and TiO2. The reaction rate constant of the optimal BT-2 composite photocatalysts for the degradation of 20 mg/L sodium ethyl-xanthate could reach 0.06496 min−1, which was 2.7 and 40.3 times than pure BiOBr and TiO2, respectively. The free radical scavenger test demonstrated that photogenerated holes were the main active species in the photocatalytic degradation reaction process. A possible degradation pathway for SEX molecules was provided through the interaction of visible light and BT-2 photocatalyst. The as-prepared BT materials can be used as efficient photocatalysts to completely degrade various types of xanthates under visible light.