Efficient Atmospheric Water Harvesting Enabled by Lithium Ethanolamine Complex/Polyzwitterion-Modified Cotton Fabrics.

Abstract

Sorption-based atmospheric water harvesting (AWH) enables the conversion of atmospheric water vapor to liquid water and is expected to play a crucial role in addressing freshwater scarcity in remote and arid regions. However, achieving a high specific surface area for rapid moisture absorption in AWH materials often necessitates complex preparation and specific loading configurations. In this study, highly swellable poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PDMAPS) and highly hygroscopic ethanolamine-decorated lithium chloride (E-LiCl) are incorporated into ordinary cotton fabrics using a simple method that combines step-drying and enrichment polymerization, achieving effective atmospheric water harvesting (1.71 g g^-1, 90% RH) in the prepared composite cotton fabrics. The contents of E-LiCl and PDMAPS in the composite fabrics are regulated by the concentration of the percussor solution, retaining the original mesh structure of the cotton fabric. The porous fabric scaffold facilitates rapid heat and air convection, enabling the composite fabrics to achieve rapid moisture absorption (1.03 g g^-1 h^-1 within the first 60 min, 90% RH) and desorption (3.08 g g^-1 h^-1 within the first 30 min, 65 °C) kinetics. When the fabric is multilayer stacked in a custom-built AWH device, the theoretical water production of the device reaches 16.2 kg m^-2 day^-1. This means that the daily water production per unit working area of the device is sufficient to meet the daily freshwater needs of approximately six individuals. This work is expected to provide insights into the low-cost preparation of high-performance AWH materials and facilitate the practical application of AWH technologies.