AUTHOR=Ortiz Nathan , Rao Sameer 

TITLE=Tailored silane based sorbent coatings for compact atmospheric water harvesting devices

JOURNAL=Frontiers in Water

VOLUME=Volume 7 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2025.1606252

DOI=10.3389/frwa.2025.1606252

ISSN=2624-9375

ABSTRACT=Sorbent coatings posses quick sorption kinetics due to their thin characteristic length scales for mass transfer and serve as an effective way to host sorbent material in a compact footprint. A tailorable coating technique is developed in this work to optimize the cycling ability of sorption based atmospheric water harvesters. Silane is used as a binding agent to adhere zeolite powder (AQSOA Z02) to thin aluminum sheets to provide a structurally sound and volumetrically dense method of packaging the sorbent while maintaining extremely fast sorption kinetics. A novel coating layering technique was used to manipulate the coating thickness slowing the adsorption times in exchange for better coating weight (kgsorbent(m2)-1). Through the multi coating technique we achieved a sorbent coating capable of collecting 1.167 kgwater(m2)-1 and when projected onto a finned heat exchanger 458 kgwater(m3)AHX-1day-1. These are highly competitive numbers especially when considering the relatively low sorbent uptake of AQSOA Z02 (32% at RH>30% and T=25°C) when compared to modern sorbents such as Ni2Cl2(BTDD) that has uptake of 80% (RH>30% and T=25°C). We outline the coating, characterization and system projection calculations which can be extrapolated in the future to modern materials and alternative form factors.