High-efficiency electrochemical decomposition of artificial sweetener aspartame using a Ti3+ self-doped TiO2 nanotube arrays anode

• Published in: Journal of environmental chemical engineering 2022-02, Vol.10 (1), p.106950, Article 106950
• Main Authors: Yu, Chengze, Zhang, Fan, Wang, Kai, Luo, Tianlie, Zhou, Chengzhi
• Format: Article
• Language: English
• Subjects: Artificial sweeteners; Electrochemical degradation; Mechanism and toxicity; TiO2 nanotube arrays anode
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2021.106950

Artificial sweeteners have attracted growing concern considering their large usage, wide detection and ecological toxicity in the last decade. In this work, high-efficiency decomposition of artificial sweetener aspartame was investigated by using a Ti3+ self-doped TiO2 nanotube arrays electrode. Effects of current density, initial concentration and inorganic anions on the degradation kinetics were studied. Results showed that the electrochemical degradation of aspartame followed pseudo-first-order kinetics, and the rate constant was 0.039 min−1 at a current density of 2 mA cm−2. The electrochemical degradation was not susceptible to nitrate, and the degradation was significantly enhanced by chloridion. Twenty-four transformation products were identified by UPLC-Orbitrap-MS/MS, and possible electrochemical degradation pathway was proposed. The degradation process of aspartame mainly included hydroxylated, demethylation, dehydrogenation, dehydration condensation and side-chain cleavage. Quantitative structure-activity relationship model revealed that the potential risks in electrolysis process should not be ignored before complete mineralization of aspartame. Energy consumption was greatly reduced in the presence of Cl-, and the lowest value for 90% aspartame degradation was 0.07 Wh L−1. The findings presented here demonstrate that electrocatalysis exhibits high efficiency in degrading aspartame and is potentially suitable for eliminating artificial sweeteners from wastewaters. [Display omitted] •Chloride accelerates the electrochemical degradation of aspartame.•Hydroxylated and dehydration condensation are important processes in degradation.•The EEO values range from 0.07 to 5.18 Wh L−1 at experimental conditions.•The potential risk should not be ignored before complete mineralization.