Synergistic reductive-oxidative removal of halogenated organics via photoelectrochemical activation of sulfite

Chlorophenols are widely used in production but are listed as priority pollutants due to their high toxicity. Traditional reduction or oxidation processes fail to achieve oxidation, dechlorination, and detoxification of chlorophenols. To address this, this study developed an efficient photoelectrochemical activation of sulfite (P UV EC/sulfite) process, combining reduction and oxidation to remove 4-chlorophenol (4-CP). P UV EC/sulfite achieved near complete removal and dechlorination for 1–10 mg L −1 4-CP within 40 min. The types and contributions of active species of P UV EC/sulfite process were explored by capture experiment and EPR test, observing that in the early stages of the reaction, reductive species such as e aq - and H* dominated while oxidative species such as • OH, O 2 •- and 1 O 2 became predominant in the later stages. P UV EC/sulfite improved the removal and dechlorination compared to reduction and oxidation alone, significantly reduced the toxicity of the pollutants. This study presents a new method for removing chlorinated organic compounds, providing new insights into the treatment of chlorinated organics.