One-step preparation of hollow cryogel particles with tunable size and polarity as high-efficiency fixed-bed filler

Separation materials have focused on porous particles with a microporous structure and a large specific surface area. However, for specific separation processes such as biomacromolecules, cell fermentation liquid, or high viscosity liquids, large pores can substantially reduce mass transfer resistance and enhance mass transfer efficiency. Therefore, a more detailed investigation is required to develop a simple method for obtaining super-macroporous particles. In this work, we presented a strategy that combined gas-shearing and sulfolane freeze casting to obtain poly (methyl methacrylate) (PMMA)-based cryogel particles with a tunable size (476–1873 μm) and polarity (contact angle of 135°–0°). The cryogel particles had a micron-scale porous structure (16.8–46.8 μm), and the volume shrinkage effect during sulfolane crystallization formed unique surface single pores (93.7–294.6 μm) and an internal hollow structure (218.4–615.6 μm). Cryogel particles with high porosity (>75 %) and good hydrophobicity had a high absorption capacity for organic solvents and oils (>15 g g −1 ). Meanwhile, the cryogel particles exhibited a column effect that was 1.3–3.9 times greater than that of the macroporous resin, along with superior adsorption kinetics. This study provides a novel strategy for obtaining super-macroporous particles with tunable particle size and composition, achieving efficient separation in special systems.