Upscale synthesis and shaping of AlPO-18 sorbent for efficient atmospheric water harvesting

Abstract

Sorption-based atmospheric water harvesting (AWH) is regarded as an efficient and sustainable strategy to alleviate the current water crisis. However, the advancement of AWH continues to be limited by the sorbents’ low efficiency, scalability challenges, and poor cycling stability. This study reports the optimization of a relevant water adsorbent, AlPO-18, with successful scale-up trials. The optimized process facilitates sing-batch production of over a hundred grams of AlPO-18 in a 1 L reactor, resulting in lower costs, reduced energy consumption, and minimized environmental impact. Notably, the upscaling doesn’t compromise the material’s sorption properties or yield, which remains consistently high at 75 % relative humidity (RH). To address the issues caused by powdered materials in industrial applications, we further demonstrate a method to shape AlPO-18 by incorporating 20 % pseudo-boehmite as a binder. The final extrudate retains the parent material’s pore structure and water sorption properties. It exhibits a high water uptake of 0.33 g/g under 75 % RH, releasing approximately 80 % of the adsorbed water within 25 min at 90 °C. Stability tests further confirm that the extrudate sorbent kept structural and adsorption capacity integrity across multiple cycles, making them highly suitable for practical applications. The research findings unambiguously prove that AlPO-18 is relevant for industrial-scale production and nondestructive shaping. This study opens the way for designing safer, more efficient, cost-effective AWH systems.