Cellulose/Chitosan Composite Sponge for Efficient Protein Adsorption

Sponges with large protein adsorption capacity are highly desired in various fields such as biosensors, biofuel cells, biocatalysis, and protein chromatography. However, the use of environmentally friendly materials and mass production still face enormous challenges. Herein, a novel and facile method to fabricate an environmentally friendly monolithic cellulose/chitosan composite sponge (CECSS) with remarkable performance is designed using the mature viscose process. The obtained highly efficient adsorption sponge exhibits a hierarchical porous structure with open-pore structures with a diameter range of 200–1000 μm and small micro/nanocellular structures (0.5–2 μm), which endow it with remarkable porosity (62.95%) and water adsorption capacity (1409%). Based on the abovementioned unique porous structure and reactive groups of chitosan, the CECSS exhibits a high bovine serum albumin adsorption capacity of 200.56 mg/g at pH 5.5 for 10 h. In addition, the adsorption of the CECSS can be well described by the pseudo-second-order kinetic model and the Langmuir isotherm model. This work provides a new sponge-forming process for the fields of protein adsorption, which may achieve the production of natural protein adsorbents at the industrial level.