Enhanced activation of PMS via Fe-MOFs-derives@BC for efficient removal of dyes: Complementary between radical and nonradical pathways

The efficient elimination of recalcitrant synthetic dyes from complex waters remains a pressing challenge for advanced oxidation processes (AOPs). Herein, an Fe-MOFs-derives@BC composite was fabricated by anchoring MIL-101(Fe) crystals onto rice-straw biochar followed by high-temperature carbonization. XRD, SEM and XPS confirm the formation of a crystal–amorphous hybrid in which residual MIL-101(Fe) nanocrystallites are embedded within a conductive carbon matrix rich in oxygen vacancies. The composite rapidly activates PMS via a synergistic Fe(II)/Fe(III) redox cycle and carbon-facilitated electron transfer, generating SO₄• − , •OH, and 1 O₂ to driving Rhodamine B (RhB) and Malachite Green (MG) degradation. Under optimal conditions (0.1 g L −1 catalyst, 0.1 g L −1 PMS), >90% RhB and MG were removed within 15 min across deionised, groundwater, lake and river matrices; even in the most complex river water, 90% removal is achieved in 10 min. When Fe-MOFs-derives@BC is immobilised in a poly (vinylidene fluoride) membrane, a continuous-flow micro-reactor maintains >90% removal over 600 min with negligible flux decline and undetectable Fe leaching. This hybrid radical/non-radical pathway, broad matrix tolerance and long-term membrane stability position Fe MOFs-derives@BC/PMS as a robust, scalable platform for advanced wastewater treatment.