Electrochemical Oxidation of Sulfonamides with Boron-Doped Diamond and Pt Anodes

Electrochemical oxidation processes usually favored specific degradation pathways depending on anode materials. In this work, a series of sulfonamides (SNs) were degraded by electrochemical oxidation. Compared to Pt anodes (0.1567-0.1795 h^-1), degradation rates of SNs were much higher at boron-doped diamond (BDD) anodes (2.4290-13.1950 h^-1). However, the same intermediates were detected in the two anode systems. Due to the strong oxidizing ability of BDD anodes, a large amount of intermediates with high toxicities were initially generated and then finally reduced in the BDD anode systems, while the amount of intermediates continuously increased in the Pt anode systems. Additionally, SNs were degraded faster in Na₂SO₄ than NaH₂PO₄ electrolytes at BDD anodes, while they were similar at Pt anodes. This study demonstrated that the degradation pathways of SNs at BDD and Pt anodes were similar, but the evolutions of intermediate amounts and toxicities were different due to their varied oxidizing abilities.