Unraveling the highly efficient synergy of adsorption and degradation for norfloxacin elimination by Mo/Fe anchored carbon fiber aerogel via peroxydisulfate activation

Abstract

In peroxydisulfate (PDS) advanced oxidation processes (AOPs), the mass transfer of reactive oxygen species (ROS) and sustainability of catalysts are the rate-limiting steps for pollutant elimination. Recently, norfloxacin (NOR) has received growing concern due to its ecotoxicological potential. Here, a novel Mo2C-Fe3C anchored in-plane biomass carbon fiber aerogel (Mo/Fe-KFA) was constructed to firstly enrich NOR on a nano-surface and immediately in situ degraded from the interface via PDS activation. Mo/Fe-KFA-PDS system achieves over 99% removal of NOR within 5 min in a wide range of pH 3–11 due to NOR fast enriched on Mo/Fe interface and enhancing the mass transfer of ROS within its lifetime. The electron transport between Mo and Fe via the graphitic carbon chain (Mo-C-Fe) in Mo/Fe-KFA accelerates the Fe3+/Fe2+ cycle and largely prolongs the durability of the catalyst which the removal of NOR is over 85% after continuous operation for 96 h with a retention time of 0.5–1 s. This means that 1 g of Mo/Fe-KFA can purify ∼43.2L of NOR wastewater driven by gravity and maintain ∼85% activity. The detailed highly removal kinetics of NOR and durability of catalyst were systematically investigated associated with DFT calculations. Finally, degradation intermediates of NOR were identified by UPLC-MS and the corresponding toxicity potential was evaluated. This work develops a sustainable, high-efficiency and economical strategy for purification of water organic contaminates.