A polydimethylsiloxane-based sponge for water purification and interfacial solar steam generation

A better knowledge for the design and synthesis of low-cost, novel porous materials is highly desirable in various fields such as recyclable solar desalination and liquid recycling. Herein, a polydimethylsiloxane-based sponge with a web-like three-dimensional (3D) interconnected porous structure was developed for effective recovery of liquids and the continuous interfacial solar steam generation (ISSG). The sponge is capable of conducting directional transport of oil or organic solvents at temperatures above 32 degrees C while automatically controlling the desorption of the organic phase below 28 degrees C. The synergistic combination between high light absorption (above 95 %) and light-to-heat conversion efficiency (99.87 %) resulted in a considerably high seawater evaporation rate (1.66 Kg m(-2)h(-1)) under 1 sun. The self-regeneration of the evaporator is facilitated by the salt barrier function of the large channels of the smart sponge with high hydraulic conductivity. This sponge can maintain a maximum evaporation rate up to the 5 consecutive days operation with the co-benefit of real-time regeneration and the reversible switching of the wettability. The reusable smart sponge evaporators are highly efficient in generating clean water from seawater with satisfactory ion rejection rates (above 99.6 %). As such, the prepared sponge shows great potential in environmental restoration, metal recovery, and water regeneration. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

A polydimethylsiloxane-based sponge with a web-like three-dimensional porous structure was developed for liquid recovery and solar steam generation. The sponge has the ability to transport liquids and control desorption, with high light absorption and conversion efficiency, resulting in a high seawater evaporation rate. The reusable sponge evaporator is efficient in generating clean water and has potential applications in environmental restoration, metal recovery, and water regeneration.