One-Step Block Copolymer Templated Synthesis of Bismuth Oxybromide for Bisphenol A Degradation: An Extended Study from Photocatalysis to Chemical Oxidation

An energy and cost-effective method was reported for bismuth oxybromide (BiOBr) preparation, and its versatile applications were investigated from the well-established photocatalysis to chemical oxidation. The performance was evaluated by bisphenol A (BPA) degradation in both photocatalysis and chemical oxidation via peroxymonosulfate (PMS) activation in terms of the efficiency of organics removal, energy consumption, and toxicity of transformative products (TPs). Different from the commonly reported mechanism involving electron−hole pairs generation in photocatalysis, the electron transfer between different valence states of the active metal site [Bi(III)−Bi(V)−Bi(III)] was proposed as the major activation mechanism in the chemical oxidation. The different reaction mechanisms affected the BPA degradation pathway, resulting in the different TPs as well as toxicity to the aqua environment. Furthermore, the potential application of BiOBr as a multiactivator for different chemical oxidants was investigated and the versatility of the block copolymer template method was tested. Overall, this work provided a much more economic and simpler method for large scale synthesis of bismuth oxyhalides via a block copolymer as the template; meanwhile, the potential applications of the material were extended to chemical oxidation, which was far beyond the widely reported photocatalysis.