Efficient Chloroquine Removal by Electro-Fenton with FeS<sub>2</sub>-Modified Cathode: Performance, Influencing Factors, Pathway Contributions, and Degradation Mechanisms
Yinghui Lin, Yingzheng Chen, Jiaxin Chen, Chen Junru, Linyan Yang, Wei Wei, Bing‐Jie Ni, Xueming Chen
Abstract
The application of chloroquine (CLQ) due to its antibacterial/antiviral nature and high potential of being persistent and bioaccumulative poses a significant environmental threat. In this study, the electro-Fenton (EF) process with pyrite (FeS 2 )-modified graphite felt (FeS 2 /GF) as the cathode (EF-FeS 2 /GF), capable of providing a stable acidic environment with a solution pH of 3.0 was constructed and found to (i) achieve 83.3 ± 0.4% 60 min CLQ removal and (ii) maintain about 60.0% CLQ removal during consecutive batch tests. FeS 2 loading amount, current density applied, and spacing between electrodes all influenced the efficacy of EF-FeS 2 /GF, with the optimum CLQ removal obtained at 10 mg, 150 mA, and 2.0 cm, respectively. Adsorption and electrocatalysis were both observed to contribute to the CLQ removal while the EF process with the verified functioning of · OH played a dominant role. Based on the detected intermediates with identified ecotoxicities, two main paths were postulated to describe the degradation processes which led to the mineralization of CLQ. These findings supported that the EF-FeS 2 /GF could be an efficient technology to treat wastewater contaminated with CLQ.