A metal-free microwave-induced carbon cloth discharge technology for efficient degradation of Rhodamine B

Conventional plasma-based advanced oxidation processes for wastewater treatment are often limited by the use of metal electrodes, which are susceptible to corrosion, secondary contamination, and poor scalability. To overcome these challenges, a novel metal-free microwave-induced carbon cloth discharge technology was developed in this study. The flexible and conductive carbon cloth acts as an efficient plasma-generation medium. Under microwave irradiation, intense localized electric fields are generated at the fiber tips, inducing dielectric breakdown at the gas-liquid interface and thereby initiating a stable plasma discharge. This process generates abundant reactive oxygen species (e.g., ·O₂^- and ·OH) that efficiently degrade Rhodamine B (RhB). Under optimal conditions (700 W microwave power, 3 g/L carbon cloth, pH 7, and Ar atmosphere), the microwave-induced carbon cloth discharge system achieves a high RhB removal efficiency of 98.42% and a significant mineralization rate (76.6% TOC removal) within 90 min. The system also demonstrates robust performance across a range of RhB concentrations, exceptional stability over multiple reuse cycles (∼95% removal efficiency after 8 cycles), and effective detoxification of the treated solution. Overall, this work presents a cost-effective, corrosion-resistant, and scalable plasma technology, offering a promising green strategy for the treatment of refractory organic wastewater.