DBD/Fe(II)/peracetic acid pretreatment mitigates nanofiltration fouling in landfill leachate treatment via coupled oxidation-coagulation and plasma-assisted iron cycling

DBD/Fe(II)/PAA couples radical oxidation with in situ Fe(III) coagulation. • Plasma-driven Fe cycling sustains PAA activation and reduces pH sensitivity. • Pretreatment increased normalized NF flux by 125% and lowered R ir by 76%. • Humic-like fluorescence fell by ~90%, with complete micropollutant removal. • NF reduced total DBPs by 92% and additive cytotoxicity by 90%. Nanofiltration (NF) can polish landfill leachate but is constrained by rapid fouling by humic macromolecules and colloids. Here, we developed a dielectric barrier discharge (DBD)/Fe(II)/peracetic acid (PAA) pretreatment that couples radical oxidation with in situ coagulation to simultaneously transform macromolecular foulants and mitigate NF fouling. Mechanistic analyses revealed that DBD facilitates Fe(II)/Fe(III) redox transformation during PAA activation, while Fe(II) serves as the catalytic center for PAA activation and the precursor for in-situ Fe(III) flocs. This dynamic generates a suite of reactive species in which hydroxyl radicals ( • OH) dominate oxidation, supplemented by organic radicals (CH 3 C( O )O • , CH 3 C( O )OO • ) and high-valent Fe(IV) = O. Oxidation reduced humic-like fluorescence by approximately 90% and removed 90–95% of three model micropollutants. Concurrently, Fe(III) generated during PAA activation aggregated oxidized organics and colloids into larger, less negatively charged flocs. This coupled transformation increased normalized NF flux by 125% and decreased irreversible resistance by 76% relative to untreated leachate. The process remained effective at pH 11 because PAA decomposition and plasma chemistry acidified the reaction medium. Subsequent NF removed 92% of chlorinated disinfection byproducts and reduced additive cytotoxicity by 90%. Economic assessment indicates an operating cost of 5.76 USD ton −1 and a carbon footprint of 0.59 kg CO 2 -eq m −3 . Unlike conventional treatments, the DBD/Fe(II)/PAA process enables plasma-assisted Fe(II)/Fe(III) redox regeneration, coupling enhanced PAA activation with in situ iron coagulation to transform and remove refractory foulants for NF fouling mitigation. This work demonstrates a cost-effective and mechanistically robust pretreatment strategy for improving NF-based landfill leachate treatment. Download: Download high-res image (192KB) Download: Download full-size image