Visible-Light-Driven BiOBr-TiO2-Attapulgite Photocatalyst with Excellent Photocatalytic Activity for Multiple Xanthates

Abstract

The novel ternary composites BiOBr-TiO2-attapulgite (BTA) were synthesized using a simple hydrothermal and water-bath method, exhibiting excellent photocatalytic performance to multiple xanthates. For the BTA photocatalyst, TiO2 and BiOBr were uniformly loaded onto the surface of acid-activated attapulgite. As a widely used collector in mining processes, sodium ethyl-xanthate (SEX) was selected as the target pollutant due to its high toxicity. The BTA ternary photocatalyst demonstrated significantly higher adsorption and photocatalytic degradation performance compared to TiO2 nanoparticles, BiOBr nanosheets, and BiOBr-TiO2 heterojunction. Structural characterization and experimental results indicated that the exceptional photocatalytic degradation efficiency of BTA was mainly attributed to the formation of a heterojunction between BiOBr and TiO2, as well as the presence of additional active adsorption sites provided by attapulgite. Free radical scavenging experiments and EPR results confirmed that the photogenerated holes were the predominant active species in photodegrading SEX throughout the entire experiment. The LC-MS results provided insight into potential degradation pathways of SEX. This research demonstrates that BTA, as a novel triple composite material, achieves rapid and complete degradation to 20 mg/L SEX within 20 min. This work presents a novel approach to synthesize mineral-based photocatalysts, which have broad prospects for application in flotation wastewater treatment.