Integration of wastewater treatment units and optimization of waste residue pyrolysis conditions in the brominated phenol flame retardant industry

Among the bromine flame retardants, tetrabromobisphenol A (TBBPA) is a highly effective flame retar-dant that can be used as both reactive and additive. However, the synthesis reaction of TBBPA has a low conversion rate and many brominated phenolic organics. Therefore, there is an urgent need to remove brominated organic pollutants produced in the process of producing flame retardants to reduce the harm to the environment and human beings and to reduce production costs. In this study, an efficient process was developed to treat the wastewater and waste residue generated in TBBPA production pro-cess, realizing its harmless and resource utilization. In the resource utilization system, through the inge-nious design of solution mixing, precipitation separation, three-effect evaporation and concentration, valuable substances were extracted to realize the recovery and reuse of wastewater. In the harmless uti-lization process of hazardous waste residue, through high-temperature pyrolysis at 500 degrees C for 2 h after optimization with hypoxia-hyperoxia atmosphere modulation, it can avoid the production of dioxins and carbon black, effectively remove the organic impurities, realize the harmlessness and obtain high -quality sodium sulfate. This paper aims to propose a simple, efficient and feasible utilization system, including the three major technological processes of TBBPA production, integrated wastewater treatment and optimized the harmless treatment of waste residue to obtain sodium sulfate, so as to realize TBBPA green production. Compared with the traditional TBBPA synthesis system, wastewater and waste residue treatment processes, the TBBPA quality is increased by 2 % and the economic cost is reduced by 10 %, which is of great significance to the development of the industry.(c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.