A hybrid linker-MOF fibrous composite for efficient diclofenac removal and self-cleaning

The treatment of emerging contaminants is essential but challenging. Herein, a novel MOF/PAN fibrous composite (TCPP@UiO-66/PAN) was synthesized and used as a self-cleaning membrane for the efficient removal of a typical emerging contaminant, diclofenac sodium (DF). The introduction of the secondary linker tetra(4-carboxyphenyl)porphyrin (TCPP) served to expand the pores and enhance its photocatalytic activity. TCPP@UiO-66/PAN shows higher adsorption capacity and initial adsorption rate than UiO-66/PAN. The maximum adsorption capacity of DF on TCPP@UiO-66/PAN reached 202 mg/g by Langmuir model. The DF adsorption mechanism involves the π-π/anion-π interaction, Lewis acid-base interaction, and hydrogen bonding. Based on the dynamic filtration experiment, TCPP@UiO-66/PAN exhibited a remarkable treatment capacity for DF-contaminated water, measuring 3.75 × 104 kg/kg. Given its fibrous membrane structure, TCPP@UiO-66/PAN could be easily separated from water and reused. In-situ photo-regeneration emerged as a highly effective method for regenerating TCPP@UiO-66/PAN after reaching adsorption saturation, with over 95 % DF degradation achieved under sunlight irradiation. The decomposition of DF primarily resulted from the generation of h+ and 1O2. Additionally, TCPP@UiO-66/PAN exhibited notable antibacterial properties when exposed to visible light. In vitro cytotoxicity assessments further confirmed the safety of these MOF/PAN composites. Combining the advantages of hybrid-linker strategy and fibrous composite, this work provided new insight into constructing MOF-based functional material for wastewater purification.