Rapid and productive extraction of high purity cellulose material via selective depolymerization of the lignin-carbohydrate complex at mild conditions
A new green cellulose extraction method – the selective degradation dissolution extraction (SDDE) method based on the [Bmim]Cl–AS (i.e. amino sulfonic acid (AS)) solvent system – was found which could rapidly extract a high yield and purity of cellulose from cornstalk at relatively low temperatures in a remarkably short time. In the SDDE method, the lignin-carbohydrate complex protective layer (LCCPL), which wraps around the cellulose, was selectively depolymerized into small molecules; as a result, the rapid dissolution of lignocellulose biomass and the efficient removal of lignin and hemicellulose from the regenerated material (RM) were successfully achieved. The cellulose content of the RM could reach 99.16 ± 0.15%, which is the highest purity of cellulose extracted from the lignocellulose biomass in one step by IL solvent systems. The delignification rate could reach 97.56 ± 0.29% while the hemicellulose was completely removed in only 1 h after the cornstalk powder was dissolved in [Bmim]Cl–AS (the AS content was 1.5 wt%) at 100 °C. The result showed that the addition of AS not only improved the purity of cellulose in the RM but also increased its yield. The yield of cellulose increased from 19.94 ± 0.45% to 71.04 ± 0.78% after the addition of AS. As the mild fractionation conditions reduced consumption of energy greatly as well as that the additive was cheap and environmentally friendly, the SDDE might be able to provide a feasible path to achieve an efficient cellulose extraction from lignocellulose biomass. In addition, utilization of the lignocellulose biomass mostly focused on the preparation of bioethanol via hydrolysis and fermentation. This work provided an alternative that high purity cellulose derivatives and cellulose composites could be produced from the lignocellulose biomass.