Ag@CuS/CC electrode promoting antibiotics removal in DBD system: Mechanism analysis and practical application

Abstract

In this study, rice-granular CuS nanoparticles are grown in situ on carbon cloth (CC) using a hydrothermal method and Ag is then loaded on the CuS/CC via ultrasonic-assisted reduction. The electrodes combined with a dielectric barrier discharge (DBD) system can improve the plasma discharge efficiency and have good oxidation properties for tetracycline, amoxicillin and sulfamethoxazole. The removal rate is further improved after adding Cr(VI). The active substances, H₂O₂ and O₃, are consumed during the process of antibiotic degradation. Trapping agent experiments indicate that h⁺, ∙OH and O₂∙⁻ play a crucial oxidation role in the reaction, with O₂∙⁻ being identified as the primary active substance. The pollutant degradation can be further accelerated by capturing e⁻ and ·H for the reduction of Cr(VI). By calculating the adsorption energies of H₂O and O₂ on the surface of Ag@CuS, it is also concluded that O₂ is easily adsorbed and preferentially generates O₂∙⁻. The residual intermediates in the samples after the degradation of tetracycline, amoxicillin and sulfamethoxazole are determined and their degradation pathways also explored. The Ag@CuS/CC-DBD system has application potential in actual wastewater treatment as it can not only reduce the chemical oxygen demand but also improve the biodegradability of wastewater.