FeNi alloy electrode assisted PMS activation strategy for degradation of trimethoprim: Charge separation mechanism and theoretical calculation

FeNi binary metal alloy anchored foam carbon composite electrode was successfully constructed by electrodeposition self-assembly strategy (FeNi@CF). FeNi with heterogeneous structure serves as a charge transfer bridge, promoting charge separation. The degradation efficiency of TMP within 20 min was 98.15 % (k = 0.1935 min −1 ). The contribution of active components to TMP degradation follows the order of SO 4 − · (63.22 %)>·OH (39.55 %)>·O 2 – (9.33 %)> 1 O 2 (5.27 %), which is consistent with the proposed charge separation mechanism. DFT calculations show that the introduction of FeNi alloy can disrupt the sp2 hybrid structure of carbon in graphite electrodes, resulting in the formation of nucleophilic and electrophilic atomic centers on their surfaces, reducing the steric hindrance of PMS adsorption (E ads  = −3.28 eV), enhancing the adsorption strength of PMS, increasing the area of active centers, and improving the activation efficiency of PMS. The free radical quenching and intermediate identification experiments further confirmed the mechanism and pathway of TMP degradation. In addition, FeNi@CF has good repeatability and stability, making it suitable for treating pollutants in various water matrices. This work is expected to provide ideas for risk assessment of various toxic and persistent organic pollutants in drinking water and wastewater.