Synthesis of one-dimensional Bi5O7Br0.5I0.5 solid solution for effective real oilfield wastewater treatment via exciton photocatalytic process

Bi5O7Br0.5I0.5 solid solution was firstly in-situ synthesized and the solid solution structure was determined by basic characterization. Here, Bi5O7Br0.5I0.5 showed enhanced photocatalytic ability for oilfield wastewater treatment than Bi5O7Br and Bi5O7I. Based on our study about photocatalytic mechanism, solid solution structure induced more singlet oxygen generation. It indicated that the origin of effective environmental photocatalytic activities should be enhanced exciton photocatalysis process of Bi5O7Br0.5I0.5 rather than the traditional carrier photocatalysis process. Due to the strong oxidizing property of singlet oxygen, the chemical oxygen demand (COD) value of oilfield wastewater reduced from 18,900 mg/L to 6800 mg/L after 5h treatment. And the foul smell and black color of oilfield wastewater were disappeared. Except for oilfield wastewater, Bi5O7Br0.5I0.5 solid solution also displayed photocatalytic activity universality for dye and phenolic pollutants degradation. This work suggested that solid solution was an effective way to improve environmental photocatalytic activity via exciton photocatalytic process. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.