Hierarchically porous zirconium-based metal-organic frameworks for rapid adsorption and enrichment of sulfonamide antibiotics

Due to serious risk to human health and eco-environmental security, antibiotics in water and foods received considerable concern. Herein, a series of stable hierarchically porous zirconium-based metal-organic frameworks (MOFs) namely HP-NU-902-X were prepared via modulator-induced defect-guided formation strategy for the first time and functioned as sorbents to removal and preconcentration of sulfonamide antibiotics (SAs). The pore size and specific surface area of HP-NU-902-X were systematically adjusted by changing concentration of monocarboxylic acid modulator. The adsorption performance of HP-NU-902-X were greatly improved by forming defects. Experiments demonstrated that HP-NU-902-80 possessed the highest adsorption efficiency to SAs. The limits of detection (S/N = 3) were achieved ranging 0.08 to 0.25 ng/mL. The spiked recoveries of water and milk samples were obtained in the range of 70.34-103.4 % and 73.83-100.5 %. Enrichment factors were calculated between 203 and 358. The SAs can be completely removed within 10 min, and adsorption kinetic data was best consistent with pseudo-second-order model. Using Langmuir isotherm model, maximum adsorption capacities for sulfadiazine, sulfapyridine, sulfametoxydiazine, sulfachloropyridazine, sulfabenzamide and sulfamethazine were calculated as 279.9, 467.7, 414.4, 433.1, 415.5 and 336.6 mg/g, respectively. The improved adsorption capacity was mainly owing to high surface area and extra defect sites. This synthetic strategy provides a way to prepare stable defective MOFs and enhance their potential applications in removal and extraction of environmental pollutants.