Superadsorption of LiOH solution on chitosan as a new type of solvent for chitosan by freezing/blasting

► Chitosan could absorb a large amount of alkali solution under freezing temperature. ► The adsorption increased with increasing LiOH concentration until 4.8 wt%. ► The adsorption of LiOH and H2O on chitosan was closely related to its DD. ► The adsorption proceeded from amorphous to crystal region. ► LiOH and the freeze-thawing treatment played key roles in the adsorption.