Evaluation of different inorganic salts in Salting‐out process of γ-valerolactone/water solutions

Lignocellulosic residual biomass is a relevant source of carbohydrates with high industrial significance. However, many factors, in particular lignin content, can limit the digestibility of cellulose and hemicellulose to simple sugars. Pre-treatments aim to improve the digestibility of lignocellulosic biomass. Organosolv is an efficient fractionation process to produce a cellulose-rich pulp with >90% and <5% cellulose and lignin content, respectively. The main problem is the high solvent consumption, which is responsible for the economic cost and environmental impacts of the process. In this study, a solvent regeneration method using the salting-out process to separate organic and inorganic solvents was evaluated. The organic solvent γ-valerolactone (GVL) in solution with water (60% w/w) was separated with different salts NaCl and Na2SO4. The salting-out process demonstrated high efficiency in GVL recovery. The study paves the way for improving the industrial feasibility and sustainability of the organosolv process in lignocellulosic fractionation. The use of salts, industrially considered a waste products, further enhances its suitability.