A Study of Hygroscopicity Improvements to Adsorbents in Solar-Powered Air Water Extraction

Abstract

As a global freshwater shortage is imminent, solar-powered adsorption-based atmospheric water harvesting technology is gradually attracting people’s attention due to its environmental friendliness and many other advantages. Among the many adsorbents used in this technology, MOF-801 has a large adsorption capacity in a wide range of humidity. In the current field, carbon materials are usually added to improve the photothermal properties of MOF-801, but hybrid adsorbents made in this way usually weaken the adsorption performance of MOF-801. If the MOF-801/carbon material adsorbent is used as a base and mixed with hygroscopic salt, which also has good adsorption properties, the hygroscopic properties of MOF-801 can be improved and the drawback of hygroscopic salt, which is prone to be lost after absorbing water, can be ameliorated. In this study, a hybrid adsorbent combining MOF-801 with carbon black (CB) and LiCl was prepared, and the effects of carbon black and LiCl on the performance of the MOF-801 adsorbent were compared. The experiments showed that the adsorption capacity of the hybrid adsorbent obtained a significant enhancement after the addition of LiCl, which increased by 38.2% versus 112.3% compared with MOF-801 and MOF-801/CB.