Trace silver doping improved the efficiency of copper-based Fenton-like catalysts cathode for wastewater treatment

Abstract

The treatment of highly concentrated and recalcitrant organic pollutants in industrial wastewater has garnered significant attention, with Fenton oxidation emerging as a promising approach. However, traditional iron-based Fenton reagents present certain limitations, and copper-based Fenton systems are often less efficient. Thus, it is necessary to develop innovative copper-based Fenton catalytic materials. In this study, Cu₂O and Ag-modified activated carbon fibers (Cu₂O-Ag@ACF) were synthesized via liquid-phase reduction. The composition, structure, and morphology of Cu₂O-Ag@ACF were systematically characterized. The Cu₂O-Ag@ACF was employed as a functionalized cathode in the electro-Fenton process to degrade a highly concentrated organic pollutant solution, with methylene blue serving as a model contaminant. The loading of Cu₂O and Ag not only enhances the electrochemical performance of ACF but also improves its Fenton oxidation efficiency. Cu₂O-Ag@ACF exhibited less than 1 % performance degradation after five cycles of use, highlighting its potential for industrial applications under simulated realistic conditions. Moreover, the electro-Fenton system parameters, including current density, pH, electrode spacing, and solution temperature, were optimized. Under the optimal conditions, the degradation rate of methylene blue by Cu₂O-Ag@ACF reached 92.8 % within 120 minutes. Kinetic analysis indicated that the reaction followed a first-order kinetic model, with a rate constant of 0.253 min⁻¹. Furthermore, this study revealed that trace silver doping significantly accelerated the generation of reactive oxygen species, thereby enhancing the efficiency of the Cu-based Fenton-like catalysts. In conclusion, this work presents a convenient strategy for the sustainable and efficient purification of industrial wastewater, contributing to the improvement of human life quality.