超稳定金属有机框架吸附剂的结构调控及水捕获性能研究

Structure regulation of ultra-stable metal organic framework forenhanced performance in water capture from air

淡水短缺是威胁人类生存的全球性挑战,特别是对生活在干旱地区的人们。捕获空气中的水是解决这一问题的一种很有吸引力的方法。然而,由于露点低、吸附剂吸水能力较低、水吸附动力学慢、高能耗等问题,目前空气水捕获技术在低湿度干旱条件下的吸附水性能较差。针对这一问题,我们通过调节超稳定金属有机框架MOF-801材料的合成温度、合成时间、物料配比和溶剂配比等因素,可以实现MOF-801晶体形貌及尺寸的有效调控。在DMF(N,N-二甲基甲酰胺)/甲酸溶剂体积配比从20/20增加到37/2.5时,水吸附性能从0.229 kg/kg增加到0.34 kg/kg,性能提升了48.5%,优于大部分文献报道的MOF吸附剂。机理研究结果表明,MOF-801孔腔对于水吸附起到决定性作用。这一研究为空气捕获水提供更多的科学与技术参考。

Freshwater scarcity is a global challenge that threatens human survival,especially for people living in arid regions.Sorption-based atmospheric water harvesting is an efficiency way to solve this issue.However,atmospheric water harvesting technology to date still suffers from low adsorption capacity under low relative humidity and drought conditions due to low dew point problem,low water uptake capacity,slow kinetics,and high energy consumption.To solve the issue,we tailored the size and morphology of ultra-stable MOF-801 absorbent by changing different parameters(synthesis time,synthesis temperature,solvent ratio,raw material ratio).The results indicated that the water uptake capacity was increased from 0.229 kg/kg to 0.34 kg/kg(enhancement ratio 48.5%),outperforming most reported MOF absorbents,when the volume ratio of DMF/formic acid solvent was increased from 20/20 to 37/2.5.The mechanism investigation revealed that cavities in MOF-801 absorbent played a key role in improving water uptake capacity.This study provided an alternative protocol for atmospheric water harvesting.