A Robust and Low-Cost Sulfonated Hypercrosslinked Polymer for Atmospheric Water Harvesting

The availability of freshwater is rapidly declining due to over-exploitation and climate change, with multiple parts of the globe already facing significant freshwater scarcity. Here, a sulfonated hypercrosslinked polymer able to repeatedly harvest significant amounts of water via direct air capture is reported. Water uptake from relative humidities as low as 10% is demonstrated, mimicking some of the harshest environments on Earth. A water harvesting device is used to show repeated uptake and harvesting without significant detriment to adsorbent performance. Desorption is triggered using simulated sunlight, presenting a low-energy route to water harvesting and adsorbent regeneration. The synthesis of sulfonated hypercrosslinked polymer requires only low-cost and readily available reagents, offering excellent potential for scale-up. Due to an almost limitless supply of water vapor from air in most regions around the globe, this approach can transform our ability to address water security concerns. A sulfonated hypercrosslinked polymer, SHCP-10, is shown to harvest significant amounts of water from air even at relative humidity as low as 10%, mimicking some of the harshest environments on earth. Equipped with a simple and low-cost synthesis, as well as good stability, SHCP-10 shows promise as a robust and reusable water-harvesting adsorbent, contributing to the tackling of water scarcity. image