Dual-functional UiO-66-(COOH)₂ mixed-matrix membrane for integrated radionuclide sequestration and catalytic degradation of pharmaceutical contaminant from water

The co-existence of hazardous radionuclides and pharmaceutical contaminants in aquatic environments underscores the urgent need for advanced materials capable of comprehensive water remediation. In this study, a novel dual-functional mixed-matrix membrane (UCM-2) was successfully fabricated by embedding a carboxyl-functionalized metal–organic framework, UiO-66-(COOH)₂, into a PVDF/PVP polymer matrix. UCM-2 exhibited outstanding dual functionality, serving as both an adsorbent and a heterogeneous catalyst. As an adsorbent, it achieved maximum uptake capacities of 5.81 mg/g for ⁶⁰Co and 4.81 mg/g for ^85,90Sr, primarily driven by electrostatic interactions and inner-sphere complexation. In parallel, the pristine UCM-2 effectively activated peroxydisulfate, enabling the rapid degradation of sulfamethoxazole, with 91.6 % removal achieved within 30 min. Scavenger experiments and ESR analysis revealed that the catalytic process was governed by a complex suite of reactive oxygen species, with superoxide (O₂^•–), sulfate radicals (SO₄^•–), and singlet oxygen (¹O₂) identified as the dominant contributors. Crucially, UCM-2 maintained robust performance for both functions even in complex aqueous matrices, including tap water, surface water, and wastewater effluent. Unlike conventional single-function adsorbents or catalysts, UCM-2 integrates both adsorption and catalytic degradation with a single, stable membrane, thereby minimizing operational complexity, while enhancing stability and reusability. This dual-functional platform can be readily extended to other radionuclide-pharmaceutical co-contaminant systems, providing a promising strategy for next-generation integrated water purification technologies.