Atomic H*-mediated electroreduction process facilitates purifying the industrial wastewater: Insights into mechanisms...

Due to the excessive chemical-energy consumption, conventional treatments (e.g. Fenton or catalytic ozonation) have faced great challenges when treating chemical wastewater containing tetrabromobisphenol S (TBBPS), a prevalent brominated flame retardant. This study proposes an electrocatalytic active atomic hydrogen (H*)-mediated electroreduction strategy, enabling enhanced degradation of TBBPS into intermediates with lower toxicity and higher biodegradability. A palladium-modified electrocatalytic microfiltration membrane (EMM) was developed to efficiently generate H*, which played a dominant role in the reductive debromination of TBBPS. By conducting quenching experiments, it was found that free H* and adsorbed H* co-dominate the TBBPS removal process. Under optimized conditions, the EMM achieved nearly complete removal (∼100%) of TBBPS (100 mg L^-1) within 60 min, with a low energy consumption of 9.53 kWh/m³. The degradation pathway of TBBPS was proposed on the results of calculations and LC-MS analysis, and the evidence demonstrated the lower toxicity of the degradation intermediates. These findings emphasize the prospects of H*-mediated electroreduction strategy as a green and environmentally friendly treatment for industrial wastewater treatment.