Construction of covalent organic framework electrospun composite nanofiber membranes for the efficient extraction and...

Phenylurea herbicides persist in the environment and food chain, posing significant public health risks. This study presented an effective method for preparing flexible covalent organic framework nanofiber membranes, composed of porous COF spheres coated with nanofibers. PAN@v-TBD membrane exhibited a stable crystal structure, high functional group density, and enhanced stability. A method for the simultaneous enrichment and determination of PUHs in wetland water, corn and tomato samples using PAN@v-TBD membrane microextraction coupled with high-performance liquid chromatography was established. The method demonstrated a wide linear range, with detection limits for wetland water (S/N = 3) ranging from 0.02 to 0.03 μg/L, and detection limits for tomatoes and corn ranging from 1.70 to 2.00 μg/kg. Recovery rates for the method ranged from 80.79 % to 108.57 %. The adsorption capacities for PUHs ranged from 24.50 to 83.96 mg/g. XPS and DFT calculations confirmed that the adsorption mechanism primarily involves electrostatic interactions, π-π interactions, C-H-π interactions, LP-π interactions, and hydrogen bonding.