Pseudosolvent swelling facilitated preparation of lignin containing cellulose nanofibers from plant residues

Lignin-containing cellulose nanofibers (LCNFs) with promising sustainability and multiple functionalities are highly in demand while still limited by the high energy consumption and potential environment disruption in preparation. In this work, the super-base system (dimethyl sulfoxide/potassium hydroxide, DMSO/KOH) was firstly employed as pseudosolvent to swell melon vine powder by partially remove some non-cellulose components (such as extraction, lignin and ash) in plant cell wall, and facilitate the following production of LCNFs. Due to the strong nucleophilicity of DMSO/KOH, universal swollen effects toward corn husk, poplar, bagasse, rice husk, and cotton stalk were achieved, and the LCNFs from them were also successfully obtained (with yields of ∼78.75%, 55.60%, 51.33%, 46.13%, and 53.90%, respectively). Besides, this method resulted in high lignin content among LCNFs (∼19.54%), which endowed the resultant membranes with superior mechanical strength, thermal stability, and dye rejection performance (a rejection rate of ∼92.7%, and a flux of 15.16 L•m-2•h-1•bar-1 toward methyl violet at 250 ppm). Thus, this research paves a simple, efficient, and universal way to prepare LCNFs from various biomass.