Electrospun Mn-doped ZIF-67 composite nanofibers with high water stability for efficient adsorption of antibiotics in aqueous systems

Currently, Zeolitic imidazolate frameworks (ZIFs) face challenges in antibiotic adsorption due to their inherent difficulty in recovery and susceptibility to hydrolysis. To overcome these limitations, herein, Mn-doped ZIF-67 was synthesized via coordination modification and then electrospun with high-mechanical-strength polyvinylidene fluoride (PVDF) to produce Mn-ZIF-67@PVP/PVDF composite nanofiber membranes. Characterization results based on SEM, XRD, and FT-IR analyses demonstrate that the layered nanofiber membrane provides abundant attachment sites for Mn-ZIF-67. Antibiotic adsorption experiments further reveal that the composite membrane exhibits facile recyclability, with Mn-ZIF-67 retaining 80 % of its initial adsorption capacity after five consecutive cycles, while maintaining its crystalline structure and remarkable aqueous stability throughout repeated utilization. The composite membrane achieved maximum adsorption capacities of 583.43 mg/g for tetracycline (TC) and 122.42 mg/g for ciprofloxacin (CIP). The adsorption process followed pseudo-first-order kinetics and Langmuir isotherm models, while thermodynamic analysis revealed a spontaneous and endothermic nature. The adsorption performance showed minimal impact from coexisting ions and pH variations. These superior characteristics of enhanced adsorption performance, exceptional water stability, and convenient recoverability endow the Mn-ZIF-67@PVP/PVDF composite membrane with significant practical advantages over conventional ZIF materials for antibiotic removal applications.