Surface Ion-Imprinted Polypropylene Fibers for Selective and Rapid Adsorption of Borate Ions: Preparation, Characterization, and Performance Study

This study presents a novel ion-imprinted fiber material, I-(PP-g-GMA-NMDG), designed for the rapid and selective adsorption of borate ions. Leveraging low-temperature plasma graft polymerization, polypropylene (PP) melt-blown fibers were functionalized with glycidyl methacrylate (GMA) and N -methyl- D -glucamine (NMDG) to introduce tailored recognition sites. Systematic optimization of plasma parameters (100 W discharge power, O 2 atmosphere) and liquid-phase grafting conditions (28.5% GMA, 85 °C, 2.5 h) achieved a grafting rate of 203.26%. The imprinted fibers exhibited exceptional adsorption performance, with a maximum capacity of 35.85 mg/g at pH 9, reaching 90% saturation within 60 min. Adsorption kinetics adhered to a pseudo-second-order model, while the Freundlich isotherm indicated multilayer adsorption. Competitive ion experiments demonstrated high selectivity for B(OH) 4 − over anions (SO 4 2− and Cl − ) and cations (Na + , K + , Ca 2+ , and Mg 2+ ), which was attributed to the precise spatial and charge complementarity of the imprinted cavities. Characterization via FT-IR, XRD, and SEM confirmed successful synthesis and structural stability. The material retained 78.1% adsorption efficiency after five regeneration cycles, showcasing its practicality for boron recovery from wastewater. This work advances boron-selective adsorption technology by combining plasma modification with ion imprinting, offering a sustainable solution for industrial and environmental applications.