Bacterial cellulose-based porous Janus aerogels for efficient interfacial solar steam generation

Interfacial solar steam generation (ISSG) is considered a green and inexpensive technology to solve water scarcity problems. Currently, it still needs to pursue a fast evaporation rate, high-quality fresh water production, and excellent mechanical properties. Herein, Janus aerogels with hydrophilic and hydrophobic structures were prepared by effective spraying of polydimethylsiloxane (PD on the upper surface of bacterial cellulose (BC) /carbon black (CB) /agar powder composites (named JBCA). After a series of experiments, the results showed that the obtained JBCA evaporator had a water evaporation rate of 1.83 kg m- 2 h-1 under 1000 W m- 2 solar radiation. Meanwhile, the same high evaporation rate (1.63 kg m- 2 h-1) was obtained in high salinity (20 wt%) solution. More importantly, the ion removal rate for real seawater was more than 99 %. The results of outdoor evaporation experiments and sustainability analyses indicated that this low-cost material with Janus structure had great potential for practical applications.