Coupling Electro-Fenton and Electrocoagulation of Aluminum-Air Batteries for Enhanced Tetracycline Degradation: Improving Hydrogen Peroxide and Power Generation.

Electro-Fenton (EF) technology has shown great potential in environmental remediation. However, developing efficient heterogeneous EF catalysts and understanding the relevant reaction mechanisms for pollutant degradation remain challenging. We propose a new system that combines aluminum-air battery electrocoagulation (EC) with EF. The system utilizes dual electron reduction of O to generate HO in situ on the air cathodes of aluminum-air batteries and the formation of primary cells to produce electricity. Tetracycline (TC) is degraded by ·OH produced by the Fenton reaction. Under optimal conditions, the system exhibits excellent TC degradation efficiency and higher HO production. The TC removal rate by the reaction system using a graphite cathode reached nearly 100% within 4 h, whereas the HO yield reached 127.07 mg/L within 24 h. The experimental results show that the novel EF and EC composite system of aluminum-air batteries, through the electroflocculation mechanism and ·OH and EF reactions, with EC as the main factor, generates multiple •OH radicals that interact to efficiently remove TC. This work provides novel and important insights into EF technology, as well as new strategies for TC removal.