The deep detoxification of tetrabromobisphenol a in a hybrid reactor system: Iron-based trimetallic and aerobic activated sludge methods

Tetrabromobisphenol A (TBBPA) is prevalent in various environmental media and biological matrices, posing considerable ecological and health risks due to its endocrine-disrupting, immunotoxic, neurotoxic, and carcinogenic properties. In this study, we developed an advanced mineralization process for the efficient mineralization of TBBPA, utilizing a hybrid system that combines zero-valent iron (ZVI) technology with an aerobic activated sludge method. A trimetallic material, s-Fe⁰-Cu-Pd, was synthesized by stepwise deposition of copper and palladium onto ZVI to improve its catalytic efficiency in degrading TBBPA. Optimal conditions for TBBPA degradation, including Cu and Pd loading ratios, initial pH, trimetallic dosage, and TBBPA concentration, were systematically investigated. The s-Fe⁰-Cu-Pd catalyst demonstrated superior performance compared to conventional ZVI and bimetallic systems, achieving 97.93 % degradation of TBBPA within 60 min, with BPA identified as the primary degradation product. Subsequent aerobic activated sludge treatment facilitated the complete degradation of intermediate products, achieving a BPA degradation rate of 100 % within 10 h. Electrochemical analyses (CV, EIS, and LSV) and DFT calculations demonstrated enhanced redox activity and electron transfer efficiency of the s-Fe⁰-Cu-Pd. Comprehensive characterization (SEM, XRD, XPS, ESR) and macrogenomic analysis were employed to elucidate the chemical and biological degradation mechanisms and to propose potential degradation pathways. This study represents the first integration of ZVI-based trimetallic catalysts with aerobic activated sludge to enhance TBBPA degradation efficiency, offering a sustainable solution for mitigating the ecological risks associated with TBBPA contamination.