Preparation of cross-linked 4-vinylpyridine porous resin and study on its HF adsorption performance

Abstract

Hydrogen fluoride (HF), a highly corrosive and toxic industrial emission, poses severe environmental and health risks, necessitating the development of efficient solid adsorbents for its capture. In this study, a series of cross-linked 4-vinylpyridine (4-VP)/divinylbenzene (DVB) porous resins were synthesized via suspension polymerization, and their HF adsorption properties were systematically evaluated. By tuning the 4-VP/DVB ratio, the pore-forming agent dosage, and the polymerization temperature, the resins' surface area, pore structure, and nitrogen content were effectively controlled. Saturation adsorption experiments revealed that nitrogen content plays a dominant role in HF uptake, whereas the contribution of specific surface area is comparatively minor. The optimized resin, WPD-25-1-0.1, achieved a high saturated adsorption capacity of 853 mg g⁻¹. Isotherm fitting demonstrated that HF adsorption follows the Freundlich model and is exothermic with heterogeneous surface characteristics. Thermodynamic analysis confirmed a strong synergistic adsorption mechanism, where pyridine nitrogen sites act as chemisorption centers and subsequently induce the formation of (HF)_n hydrogen-bonded clusters. The resin also demonstrates excellent regenerability, maintaining over 97% capacity retention after five adsorption–desorption cycles using only N₂ purging at 373 K. These results highlight the strong potential of 4-VP-based porous resins for industrial HF emission control and resource recovery.