Eco-friendly and underwater superelastic cellulose nanofibrous aerogels for efficient capture and high-throughput protein separation

High-performance and environmentally compatible chromatographic media with superb adsorption capacity and large processing throughput is key to efficient protein separation. Herein, composite aerogels (CCS-NFAs) of cellulose nanofibrous and chitosan (CCS) with 3D lamellar structure were developed by freeze-drying method for adsorptive separation of protein. The CCS-NFAs exhibited good under water strength (25.2 kPa at 60 % compression strain) and underwater superelasticity despite being highly porous (over 98%) and lightweight (10.94 mg cm-3). The maximum adsorption capacity for bovine serum albumin (BSA) was calculated to be about 1269 mg g-1, and the corresponding dynamic adsorption capability was as high as 914 mg g-1 with a filling mass of 20 mg at a flow rate of 30 mL h-1, compared favorably against the state-of-the-art ion-exchange chromatography materials. The superb adsorptive capacity was due to the involvement of chemical adsorption as confirmed by the pseudo-second-order kinetic model and Langmuir model fitting of the experimental data. Additionally, the highly oriented large open-cells in the material enabled ultrahigh water flux at about 2.2 x 104 L m-2h-1, which showed no significant attenuation in flux or removal efficiency. The successful preparation of CCS-NFAs contributes to protein purification engineering by offering an eco-friendly high-performance chromatographic media.