Investigation of adsorption-electrochemical degradation properties of Cu-doped ZIF-8/MWCNTs/CC anode materials against emerging organochlorine contaminants in wastewater

Adsorption-electrocatalytic oxidation is a promising technology for organochlorine removal; however, its practical application is hindered by electrode limitations in activity, stability, and mechanistic understanding. In this study, a copper-doped ZIF-8/multi-walled carbon nanotube composite electrode (Cu-ZIF-8/MWCNTs/CC) was innovatively designed. Adsorption-electrochemical batch experiments were conducted to systematically investigate the degradation behaviors of three typical organochlorine contaminants: 2,4-dichlorophenol (2,4-DCP), triclosan (TCS), and chloramphenicol (CAP), using MOF-based electrodes. The results demonstrate that compared to the undoped ZIF-8/MWCNTs/CC, the incorporation of Cu introduced additional mesoporous structures and Cu-N coordination bonds, which effectively enhanced adsorption performance based on the size-matching effect and d-band center theory. Furthermore, the highly reversible and kinetically rapid Cu 2 + /Cu + redox couple served as an efficient mediator for charge transfer, thus promoting the synergistic adsorption and electrochemical degradation of organochlorine contaminants. Notably, the material maintained considerable removal efficiency even under competitive conditions in multicomponent systems. Mechanistic investigation demonstrated that hydroxyl radicals (·OH) preferentially attacked critical chemical bonds (including C-Cl, ether, and amino groups) in accordance with density functional theory (DFT) predictions. This reaction pathway resulted in the generation of less toxic intermediates that were eventually mineralized into CO 2 and H 2 O. The ecological structure-activity relationships (ECOSAR) model further confirmed the low acute and chronic toxicity of the major degradation products. Moreover, the electrode maintained high removal efficiency across multiple consecutive cycles, demonstrating excellent stability and reusability. Collectively, this work proposes a novel strategy for the synergistic adsorption and electrocatalytic removal of organochlorine contaminants; thereby highlighting its significant potential for practical application.