Fabrication of Cellulose Nanofiltration Membranes by Reusing a Binary Solvent of EMIMAc Ionic Liquid and DMSO

Cellulose, a sustainable raw material, holds great promise as an ideal candidate for membrane materials. This work focused on establishing a green route for fabricating cellulose nanofiltration membranes by reusing a binary solvent of a mixture of ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate and dimethyl sulfoxide (DMSO). The rheological and thermodynamic properties of cellulose solutions were thoroughly investigated to gain fundamental insights into cellulose membrane formation using a mixture solvent. The morphologies and separation performances of the cellulose membranes were also studied. Based on these results, we successfully developed a cellulose membrane with a remarkable water flux of 101.8 L/m²·h, and the rejections for both Congo Red and Evans Blue were higher than 99.7%. Furthermore, the cellulose membrane demonstrated excellent antifouling performance and stability in long-term operation. Moreover, we conducted an attempt on the recycling and reuse of IL and DMSO, revealing that the structure and separation performance of the cellulose membrane produced using the recovered solvent were comparable to those of the membrane obtained using the original solvent. These results highlighted a sustainable approach to fabricating high-performance cellulose membranes.