Degradation of acesulfame in aqueous solutions by electro-oxidation

• The direct oxidation of acesulfame (ACE-K) on tested anodes is not detected in CV.
• The ACE-K degradation and TOC removal are in the order BDD > PbO2 > Pt.
• The ACE-K degradation efficiencies are similar in municipal wastewater matrices.
• The TOC removal follows the order of ABT ≈ IN > BBT in wastewater matrices.
• Complete mineralization of ACE-K and TOC can be achieved.

The electrochemical oxidation of acesulfame (acesulfame potassium (ACE-K)) on different electrodes or in various aqueous solutions was investigated in this study. The performance in terms of ACE-K degradation and total organic carbon (TOC) removal of tested anodes was in the order boron-doped diamond (BDD) > PbO2 > Pt, although ACE-K could not be directly oxidized on these electrodes in cyclic voltammetric analysis. At the same electrolysis time, the ACE-K degradation and TOC removal efficiencies increased with an increasing current density or anode area, but decreased with the increase of initial ACE-K concentration. The ACE-K degradation was slightly influenced by temperature at 25−50 °C. The apparent pseudo-first-order rate constants of ACE-K oxidation were similar in ACE-K-spiked 1 M Na2SO4 solution and municipal wastewater matrices (influent (IN), before biological treatment (BBT), and after biological treatment (ABT)) ((1.73 – 2.32) × 10−3 s−1). Although the TOC removal (consistent with mineralization current efficiency) in these wastewater matrices followed the order ABT ≈ IN > BBT, the complete mineralization of ACE-K and TOC was achieved. Accordingly, the electrooxidation process has great potential to be used to improve the biodegradation-resistant ACE-K degradation and TOC removal in secondary biological wastewater treatment.

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