High-yield solar-driven atmospheric water harvesting with ultra-high salt content composites encapsulated in porous membrane

Sorption-based atmospheric water harvesting (SAWH) is recognized as a feasible and sustainable approach to address global water scarcity in arid regions. However, easy-to-prepare and inexpensive saltbased sorbents have stringent requirements referring to sorption duration and environmental humidity; otherwise, the leakage of salt solution can occur. Here, we develop a composite sorbent with remarkably high salt content of 80 wt % and without the risk of leakage by introducing a polytetrafluoroethylene membrane encapsulation method. The developed composite HSCC-E10 shows both fast sorption kinetics inherent to the matrix of composites and high absorption capacity of hygroscopic salt solutions, achieving ultra-high sorption capacity of 3.75 g/g, 2.83 g/g, and 1.47 g/g for 90%, 70%, and 30% relative humidity (RH), respectively. A lab-scale device is developed demonstrating 560 mL/m(2) water yield under outdoor natural sunlight. The applicability of proposed sorbents could pave the road for future middle- or large-scale applications, such as vehicle-mounted and continuous SAWH.

Automated summary

A composite sorbent with high salt content and polytetrafluoroethylene membrane encapsulation method was developed, showing high sorption capacity without leakage. The experiment results demonstrate that the sorbent has high absorption capacity at different humidities, which could support future middle- or large-scale applications.