High-efficiency electro-catalytic performance of green dill biochar cathode and its application in electro-Fenton process for the degradation of pollutants

Abstract

Biochar (BC) is a kind of carbon-rich, renewable and low-cost material, which can be prepared from various organic materials. In this work, biochar was used as the electrode material to prepare a novel rolled electrode as a cathode for the Electeo-Fenton (EF) system. The results showed that a quite high generation of H₂O₂ (609 mg L⁻¹) could be obtained on the optimum-mixed cathode of carbon black and biochar (BC–CB-(1 : 1)) at a low electric energy consumption (EEC) (32.8 kW h kg⁻¹). Furthermore, the operating parameters such as airflow rate, pH, and current density, affecting the H₂O₂ electro-generation, were investigated and optimized. The optimum conditions for H₂O₂ generation were air flow rate 0.6 L min⁻¹, current density 32 mA cm⁻² and initial pH 7.0. The achieved removal rate of tetracycline was 95.3% within 10 min, and the TOC mineralization could reach 91% on the optimum mixed cathode, which was much higher than that of raw biochar cathode. In terms of stability, the mixed cathode remained stable after 10 cycles. The optimized design considerably improved the electrochemical performances of the electrode, which offer a cost-effective strategy for organic pollutant removal by the EF process.