A Highly Stable Ortho-Ketoenamine Covalent Organic Framework with Balanced Hydrophilic and Hydrophobic Sites for Atmospheric Water Harvesting.
Liang-Hui ChenWang-Kang HanXiaodong YanJiangwei ZhangYuqin JiangZhi-Guo GuPublished in: ChemSusChem (2022)
Atmospheric moisture is a sustainable clean water source that can solve the shortage of fresh water in arid areas. Herein a 2D covalent organic framework (COF-ok) was reported as a promising porous sorbent for solar-driven atmospheric water harvesting. COF-ok with ortho-ketoenamine linkage was extremely stable in harsh environment, including in boiling water, strong acids and bases. Because of the balanced hydrophilic and hydrophobic sites in channels, COF-ok showed a high water uptake of 0.33 g g -1 at a low relative humidity of 34 % featuring a characteristic S-shaped water sorption isotherm with low regeneration temperature (∼45 °C) and excellent cyclic stability. A laboratory-scale water harvesting system could collect water of 161 g kg -1 under sunlight.