DLP Printing of β-Cyclodextrin-Functionalized Hierarchically Porous Polymer Monoliths for Efficient Micropollutant Removal

Abstract

β-Cyclodextrin (βCD)-based adsorbents have emerged as promising materials for micropollutant removal owing to their host–guest recognition capability toward diverse organic molecules. However, developing βCD-based monolithic adsorbents that simultaneously achieve high adsorption capacity and rapid mass transport remains challenging. Here, we report a βCD-functionalized hierarchically porous polymer monolith fabricated by integrating digital light processing (DLP) 3D printing, polymerization-induced phase separation (PIPS), and supramolecular post-modification. By optimizing the porogenic solvent composition of the printing inks, nanoporous polymer monoliths with interconnected submicron pores, a porosity of 23.49%, an average pore diameter of 0.20 μm, a specific surface area of 28.33 m² g^–1, and adequate compressive strength were obtained. Subsequent βCD grafting introduced host–guest adsorption sites, enabling βCD-Nano-P to achieve an equilibrium BPA uptake of 77.52 mg g^–1 at 1 mM BPA, which was 37.5% higher than that of the βCD-modified nonporous control. The βCD-Nano-P monolith also showed good reusability over five adsorption–desorption cycles and broad removal capability toward different organic pollutants. Importantly, DLP printing enabled the construction of hierarchically porous monoliths with triply periodic minimal surface macropores, which accelerated adsorption kinetics by increasing the adsorption rate constant 12.4-fold compared with the nanoporous monolith without macropores. This work demonstrates a multiscale design strategy that integrates βCD adsorption sites, PIPS-generated nanopores, and DLP-designed macroporous flow pathways to simultaneously improve adsorption capacity and adsorption kinetics in structured water-treatment adsorbents.