High mechanical strength cellulose microspheres with homogeneous regeneration framework achieved by mild solvent exchange strategy for adsorption of flavonoids

A weakness in compressive strength of cellulose microspheres has greatly restricted its application, especially in separation and purification. Herein, a novel strategy called mild solution exchange (MSE) is proposed to construct cellulose microspheres of high strength and permeability (MCM). MSE strategy provides cellulose chains with more sufficient assembling and stacking in antiparallel orientation, achieving homogeneous regeneration of cellulose framework, eventually results in higher crystallinity of cellulose microspheres. In particular, MCMs exhibit lower back pressure, higher permeability than cellulose microspheres fabricated via normal solution exchange strategy (NCM). Meanwhile, reserving hierarchical macro-meso-micropore renders MCM of outstanding mass transfer rates and abundant adsorption sites. Besides, the proposed microspheres are modified with 4-Formylphenylboronic acid (BA-MCMs) and then applied to adsorption evaluation. Excellent structural features and specific functional groups provide adsorbents with outstanding adsorption capabilities toward cis-diol-containing molecule. BA-MCMs show a high adsorption capacity, fast separation and excellent breakthrough characteristic.