A Janus-type hygroscopic hydrogel for reusable robust dehumidification and efficient solar thermal desorption

Abstract

High humidity can lead to hazards such as disruptions in basic human metabolism, machines corrosion, bacteria breeding and so on, which make it an urgent need to develop efficient, reusable, and environmentally friendly dehumidifying materials. Herein, a reusable Janus-type cellulose nanofibrillated based hydrogel (CNH) @ graphene oxide matrix photothermal composite (GMC) hygroscopic hydrogel with porous three-dimensional network and solar thermal surface is manufactured by combining lyophilization and spray coating. The outstanding hygroscopic property of lithium chloride and excellent water storage capacity of biomass-based cellulose nanofibrillated three-dimensional network endow the Janus-type CNH@GMC hygroscopic hydrogel (CGH) with robust air dehumidification performance, while the evenly dispersed GMC with excellent photothermal properties provides the CGH with efficient solar thermal desorption performance. Consequently, the CGH can efficaciously achieve a moisture absorption of 459.3% of its weight and desorption of 82.5% of the absorbed water in static circumstances. More interestingly, a channel with flowing wind is constructed to explore the dynamic dehumidification effect of CGH, finding that the CGH can reduce the relative humidity in the danamic channel from 97.1% to 39.2%. These results mean that CGH can dehumidify air in both static and dynamic circumstances, highlighting its potential for reusable, sustainable, and environmentally friendly dehumidification.