Augmented degradation performance of dielectric barrier discharge plasma via optimized hydroxyl radical generation

Abstract

Dielectric barrier discharge (DBD) plasma demonstrates significant potential for eliminating chlorinated aromatic compounds (CACs), while its commercial application has been hampered by inadequate generation and diffusion of active species. In response, this work introduced iron-biochar composites (Fe/BC) into DBD system to enhance the generation of highly oxidative hydroxyl radicals (OH) from underutilized O3 and H2O2, thereby reducing the diffusion of OH and accelerating the degradation of CACs. The results indicated that, in just 15 min, the combined system achieved remarkable degradation rates exceeding 95% for six diverse CACs, with the degradation rate constant increasing up to 4.27 times when compared to DBD alone. Moreover, the varied response of pollutants implied that the enhanced degradation efficiency was primarily facilitated by the reduced mass transfer distance between pollutants and formed OH. The activation of O3 on Lewis acidic sites not only directly promoted the generation of OH through free radical chain reactions but also indirectly induced more conversion of H2O2 into OH by facilitating the Fe3+/Fe2+ cycle. The identification of intermediates and toxicity analysis substantiated its environmental sustainability. This study offers a viable technical pathway and theoretical foundation for enhancing the efficiency of plasma-based treatment of organic wastewater.