Thermally engineered ER-Fc-MOF@foam carbon monoliths for polyethylene microplastic remediation: Integrating interfacial capture with Fenton-like oxidative transformation

ER-Fc-MOF@CF monolith integrates PE capture and Fenton-like oxidation. • Carbonization tunes conductivity, defects, and MOF anchoring on CF. • CF-900 achieves 91.14% PE removal under flow-through conditions. • Captured PE undergoes localized ROS-mediated surface oxidation. • Monolithic design reduces powder catalyst loss and secondary release. Microplastic remediation requires efficient particle capture and interfacial oxidation because dispersed polymers have limited contact with short-lived reactive oxygen species (ROS) in bulk solution. Here, an electroresponsive ferrocene metal–organic framework (ER-Fc-MOF) was grown in situ on thermally engineered foam carbon (CF) to construct ER-Fc-MOF@CF monoliths for polyethylene microplastic capture and subsequent electro-Fenton-like treatment. Carbonization temperature regulated the scaffold architecture, surface chemistry, defect structure, electrical resistivity, and ER-Fc-MOF coverage. Among the investigated samples, CF-900 retained accessible hierarchical porosity while exhibiting the lowest resistivity and densest ER-Fc-MOF coverage. The optimized ER-Fc-MOF@CF-900 achieved 91.14% flow-through removal from a 100 mg·L −1 polyethylene (PE) suspension. Zeta-potential, FTIR, and XPS analyses suggested pH-dependent electrostatic attraction and localized polar interactions involving oxygen-containing groups, while the interconnected monolith facilitated particle interception and retention. The low-resistance CF-900 scaffold supported electron transport and H 2 O 2 activation at ER-Fc-MOF domains. SEM, EDS, FTIR, and XPS showed progressive PE surface oxidation, including roughening, oxygen enrichment, and increased C O, C O, and O–C=O signals, while EPR identified ·OH, ·O 2 − , and 1 O 2 . After 36 h, dissolved organic carbon (DOC) reached 67.21 mg·L −1 in the PE-containing system versus 8.80 mg·L −1 in the PE-free control, supporting PE-associated dissolved organic carbon release. This work establishes a self-supporting MOF–carbon platform coupling PE capture, flow-through interception, and interfacial oxidative transformation. Download: Download high-res image (205KB) Download: Download full-size image