Citric acid modulated strong magnetic CoFe-LDH/CoFe2O4 coupled dielectric barrier discharge plasma for efficient levofloxacin degradation: Enhanced internal electric field and accelerated electron migration

A novel citric acid (CA) modulation strategy was developed to prepare strong magnetic CoFe-LDH/CoFe2O4-C composites, which were combined with dielectric barrier discharge (DBD) to effectively degrade levofloxacin (LEV) in wastewater. Kelvin probe force microscopy (KPFM) test showed that CA modulation facilitated a more powerful internal electric field to drive rapid charge migration. The addition of CoFe-LDH/CoFe2O4-C increased LEV degradation from 78.2 % to 98.6 % and reduced energy efficiency from 24.77 to 8.93 kWh m–3. Quenching experiments and electron paramagnetic resonance (EPR) spectra showed the CoFe-LDH/CoFe2O4-C could take full advantage of the active substances originating from DBD plasma and highlighted the role of 1O2 and ·O2–. Density functional theory (DFT) calculation revealed that the heterojunction can not only drive faster electron migration but also reduce the energy barrier of O3 decomposition. Possible degradation pathways for LEV were proposed. This study opened up a new avenue for the synthesis of applicable catalysts for plasma systems in water treatment areas. [Display omitted] ●Citric acid modulation enhanced the internal electric field in CoFe-LDH/CoFe2O4.●Faster electron migration and energetic metal redox cycle existed in composites.●Dielectric barrier discharge (DBD)/CoFe-LDH/CoFe2O4 process has higher reactivity and lower energy consumption.●Composites effectively activated DBD-generated ROS and boosted removal efficiency.