Guan Weixin, Lei Chuxin, Guo Youhong, Shi Wen, Yu Guihua
Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
Adv Mater. 2024 Mar;36(12):e2207786. doi: 10.1002/adma.202207786. Epub 2022 Nov 13.
Sorbent-based atmospheric water harvesting (AWH) has emerged as a promising decentralized water-production technology to mitigate the freshwater crisis in arid areas. Hydrogels have been regarded as attractive sorbents due to their high water retention and tailorable polymer-water interactions. Yet, the kinetics of water sorption and desorption at low relative humidity (RH) shall be improved for their practical implementation. Here, hygroscopic microgels (HMGs) composed of hydroxypropyl cellulose (HPC) and hygroscopic salt are reported, which achieve a water uptake of ca. 0.5-0.8 g g at 15-30% RH. HMGs enable rapid sorption-desorption kinetics owing to the short-distance diffusion in the microgels and hydrophilicity-hydrophobicity switching of the thermoresponsive HPC. To validate the feasibility of HMGs for moisture extraction, a potential daily water collection of up to equivalent 7.9-19.1 L kg at low RH is demonstrated, enabled by 24-36 operation cycles per day based on the material-level experiments. With renewable raw materials and superior performance, HMGs provide a sustainable approach for rapid moisture extraction in arid climates.
基于吸附剂的大气取水（AWH）已成为一种有前景的分散式制水技术，以缓解干旱地区的淡水危机。水凝胶因其高保水性和可定制的聚合物-水相互作用而被视为有吸引力的吸附剂。然而，在低相对湿度（RH）下的水吸附和解吸动力学仍需改进以实现其实际应用。在此，报道了由羟丙基纤维素（HPC）和吸湿盐组成的吸湿微凝胶（HMG），其在15 - 30% RH下的吸水量约为0.5 - 0.8 g/g。由于微凝胶中的短距离扩散以及热响应性HPC的亲水-疏水转换，HMG实现了快速的吸附-解吸动力学。为验证HMG用于水分提取的可行性，基于材料级实验，通过每天24 - 36个操作循环，证明在低RH下潜在的日取水量高达7.9 - 19.1 L/kg。凭借可再生原料和卓越性能，HMG为干旱气候下的快速水分提取提供了一种可持续的方法。
