Chitin nanocrystals scaffold by directional freezing for high-efficiency water purification

Rapid and energy-saving water purification is urgently needed to solve the increasingly severe water shortage problem. Herein, we prepared chitin nanocrystals (ChNCs) scaffolds with aligned channels by the liquid nitrogen -assisted directional freezing method. The aligned channel in the porous ChNCs scaffold can quickly adsorb water to a saturation state. Glutaraldehyde crosslinked ChNCs scaffold (XChNCs) had good mechanical and water stability, which could float on the water surface stably. The ink coated XChNCs scaffold achieved a high evap-oration rate of 4.45 kg m-2 h-1 under 1 sun irradiation. Moreover, XChNCs scaffold showed excellent salt, acid, and alkali resistance in the oil-water separation experiment. The XChNCs scaffold showed excellent dye adsorption performance because of its high porosity, and the adsorption ratio of both methylene blue and Congo red dyes exceeded 95 %. This work prepared a renewable, biodegradable, high-performance scaffold derived from biomass, which shows promising application in water purification such as seawater desalination, oil-water separation, and dye adsorption.