Electrochemical oxidation of organic pollutants and simultaneous capture of generated carbon dioxide in wastewater treatment.

CO2 from organic pollutants degradation in wastewater represents a significant but often overlooked greenhouse gas source. This study presents an integrated electrochemical strategy for simultaneous pollutants degradation and in-situ capture of the generated CO2 to produce functional materials. Organic pollutants were mineralized by •OH, SO4•- and active chlorine. The generated CO2 migrated to the cathode and was captured by OH- from hydrogen evolution reaction. Subsequently, carbonate species reacted with native Ca2+ in wastewater, inducing CaCO3 precipitation with a negligible effect on electrode properties. Under optimal conditions, a CO2 capture ratio of 83.4% was achieved, with 86.4% fixed as CaCO3. The transformation of CaCO3 polymorph was governed by local pH and supersaturation. Techno-economic and carbon footprint analysis indicated that this technology could achieve positive return and net carbon emissions. This work couples organic pollutant removal with in-situ CO2 conversion into high-value vaterite, advancing sustainable wastewater treatment with improved resource efficiency.