Enhanced levofloxacin degradation through efficient activation of peroxymonosulfate using N-doped bulged multilayer Graphene: Harnessing interface structure to regulate carrier concentration and transport speed

Abstract

Nitrogen (N)-doped carbon materials are regarded as potential catalysts for advanced oxidation procedures due to their efficiency and environmentally friendly nature. Nevertheless, the low carrier concentration, slow charge transfer, and limited mass transfer efficiency hinder satisfactory catalytic performance. Herein, we present the novel use of graphite nanosheets as precursors to synthesize nanoporous N-doped mesoporous expanded and bulged multilayer graphene (EG@N-x) with varying proportions for peroxydisulfate (PMS) activation. The EG@N-2.5 catalyst demonstrates a degradation rate of 0.140 min−1, and over 90 % of LEVO (24 mg/L) was decomposed in 10 min. Additionally, the EG@N-2.5/PMS system possessed a broad pH range of efficiency (1.0–7.0), exceptional anti-interference performance against anions and humic acid (HA), and marvelous reusability, which can be attributed to the superior PMS activation performance of EG@N-x by lowering the EHOMO − ELUMO (EPD = 0.014433) gap, and reducing the adsorption binding energy (Eads = -2.33 eV), enhancing the amount of charge transfer (Q = 0.6190 e) in the EG@N-x/PMS system. The removal of LEVO is primarily attributed to the mechanism of singlet oxygen (1O2) mechanism and the metastable reactive complexes in electron transfer. Decarboxylation, defluorination, and depiperazinylation are three dominant reaction pathways. Moreover, the EG@N-x/PMS system demonstrates adequate mineralization of LEVO under various organic and environmental conditions, reducing effluent biotoxicity.