Integrating Reactive Chlorine Species Generation with H 2 Evolution in a Multifunctional Photoelectrochemical System for Low Operational Carbon Emissions Saline Sewage Treatment.

Conventional wastewater treatment plants (WWTPs) suffer from high carbon emissions and are inefficient in removing emerging organic pollutants (EOPs). Consequently, we have developed a low operational carbon emissions multifunctional photoelectrochemical (PEC) system for saline sewage treatment to simultaneously remove organic pollutants, ammonia, and bacteria, coupled with H 2 evolution. A reduced BiVO 4 (r-BiVO 4 ) photoanode with enhanced PEC properties, ascribed to constructing sufficient oxygen vacancies and V 4+ species, was synthesized for the aforementioned technique. The PEC/r-BiVO 4 process could treat saline sewage to meet local WWTPs' discharge standard in 40 min at 2.0 V vs Ag/AgCl and completely degrade carbamazepine (one of EOPs), coupled with 633 μmol of H 2 production; 93.29% reduction in operational carbon emissions and 77.82% decrease in direct emissions were achieved by the PEC/r-BiVO 4 process compared with large-scale WWTPs, attributed to the restrained generation of CH 4 and N 2 O. The PEC system activated chloride ions in sewage to generate numerous reactive chlorine species and facilitate • OH production, promoting contaminants removal. The PEC system exhibited operational feasibility at varying pH and total suspended solids concentrations and has outstanding reusability and stability, confirming its promising practical potential. This study proposed a novel PEC reaction for reducing operational carbon emissions from saline sewage treatment.