Harnessing singlet oxygen for advanced electrochemical treatment of coking wastewater

Refractory organic compounds (ROCs) in high salinity coking wastewater present a significant challenge to effective treatment. In this study, we employ a Pd-loaded porous titanium anode in an electrochemical advanced oxidation process (EAOP) to degrade ROCs with singlet oxygen ( 1 O 2 ) as the primary reactive species. At 5 ​mA/cm 2 , the Pd/PdO x /Ti system achieved a 92.3 ​% ROCs removal within 4 ​hours and maintained excellent stability over multiple cycles. Analytical analyses indicate the breakdown of complex organics into small molecules. Electron paramagnetic resonance (EPR) spectroscopy identified that 1 O 2 as the dominant reactive species. Thus, this process suppresses the generation of chlorinated by-products, highlighting its suitability in treating real-world high-salinity wastewater. In addition, the Pd/PdO x /Ti anode exhibited lower energy consumption (61 ​± ​2.3 ​kWh/kg) and higher current efficiency (23.2 ​%), compared to the commercial Ir/Ta and BDD electrodes, underscoring its potential as an energy-efficient and reliable solution for coking wastewater treatment.