A Sulfonated Covalent Organic Framework for Atmospheric Water Harvesting

We report a sulfonated covalent organic framework (COF) capable of atmospheric water harvesting in arid conditions. The isothermal water uptake profile of the framework was studied, and the network displayed steep water sorption at low relative humidity (RH) in temperatures of up to 45 °C, reaching a water uptake of 0.12 g g ⁻¹ at 10 % RH and even 0.08 g g ⁻¹ at just 5 % RH, representing some of the most extreme conditions on the planet. We found that the inclusion of sulfonate moieties shifted uptake in the water isotherm profiles to lower RH compared to non-sulfonated equivalents, demonstrating well the benefits of including these hydrophilic sites for water uptake in hot, arid locations. Repeated uptake and desorption cycles were performed on the material without significant detriment to its adsorption performance, demonstrating the potential of the sulfonated COF for real-world implementation.
A sulfonated covalent organic framework, COF-SO3H, effectively harvests atmospheric water, exhibiting steep water sorption at low relative humidity. The inclusion of sulfonate groups shifts uptake to lower relative humidity, enhancing performance in extreme, arid environments. The framework retains adsorption efficiency over multiple cycles, demonstrating practical potential. image