Efficient air water harvesting of TpPa-1 COFs@LiCl composite driven by solar energy

Abstract

Adsorbent-assisted air water harvesting (AWH) may help alleviate the current global freshwater scarcity crisis. However, the weak sorption capacity of various adsorbents and the high energy required to release water are two long-standing problems. Herein, we propose a class of green and clean adsorbent, TpPa-1@LiCl composite, whose sorption capacity is greatly improved to 0.37 and 0.80 ​g ​g⁻¹ under 30% and 90% relative humidity (RH), respectively, and which has excellent stability, showing only a slight decrease (0.79%) after 10 sorption–desorption cycles (1400 ​min). This TpPa-1@LiCl composite can reach equilibrium within 2 ​h and undergo complete desorption in 30 ​min under air mass 1.5 ​G irradiation. A corresponding solar-driven AWH device can complete up to 4 sorption–desorption cycles per day, with each cycle capable of collecting 0.34 ​g ​g⁻¹ water without additional energy input, which implies TpPa-1@LiCl composite has the potential for achieving sorption-assisted AWH with high efficiency and rapid cycling.