Location: Zoom: 828 685 7838; the video will be shown in CPE 2.222 at UT Austin
Sponsor: Department of Energy (DOE) Energy Frontier Research Center (EFRC) Materials for Water and Energy Systems (M-WET)
Title: Freshwater from air using moisture-capturing hydrogels: Soft matter, transport, and sorption for sustainability and energy
Abstract
Humidity in the air is a vast water resource representing 6 times more freshwater than all rivers and lakes. This humidity can be converted to drinking water via moisture sorption-desorption, serving as a potentially decentralized, passive, and low-cost pathway to mitigate the pressing water scarcity challenge. However, the productivity and potential of this approach have been severely limited by the performance, scalability, and durability of conventional moisture sorbent materials. In this talk, I will discuss the material-level to application-level development of low-cost (<$0.1/kg of material) hydrogel-salt composites that capture record amounts of water from the air and produce liquid water even in extreme conditions like the Atacama Desert, Chile.
Firstly, I will discuss the physics-based models we developed to elucidate the key thermodynamic interactions and transport mechanisms in hydrogel-salt composites. Through comprehensive synthesis and characterization, we demonstrated that these models accurately predict the sorption performance metrics (uptake, enthalpy, and kinetics) of hydrogel-salt composites from their composition. Secondly, I will present how these insights guided the synthesis of hydrogels with the highest capability ever demonstrated of any material to capture and store water from the air (~2 kg of water/ kg of material), even in arid conditions (30% relative humidity) through an optimized swelling-based approach. Thirdly, I will discuss how our thermodynamic and transport models guided the design of a hydrogel-based atmospheric water harvesting device that was tested in the Atacama Desert, in Chile. Using these models, we tuned key design parameters to achieve ~1 L/m2/day water productivity even at ~30% relative humidity in the desert. Critically, through the demonstrated combination of low-cost, high productivity, and high material durability, we provide a path towards <$0.01/L decentralized water production from air.
I will conclude the talk by discussing other research directions in our group at the intersection of soft materials and sustainability in carbon capture, critical minerals, biomass processing, and building decarbonization.
Bio
Carlos D. Diaz-Marin is an Assistant Professor in the Department of Energy Science and Engineering at Stanford University. Carlos leads the DELTA group, working at the intersection of soft materials and transport phenomena for applications in energy, emissions, and water. Current areas of focus include materials and systems for water production from air, carbon capture powered by data center heat, selective lithium crystallization from brine, and phase change of water in hydrogels.Carlos was an ARPA-E ORISE Fellow at the Advanced Research Projects Agency - Energy (ARPA-E) within the US Department of Energy. He obtained his MS and PhD in Mechanical Engineering at MIT and double undergraduate degrees in Mechanical Engineering and Physics from the University of Costa Rica. Carlos has been recognized as a Finalist for the Global Prize for Innovation in Water (2025), Rising Star in Soft and Biological Matter (2024), Rising Star in Mechanical Engineering (2023), the Caltech Young Trailblazing Researcher in Mechanical and Civil Engineering (2023), and as an MIT Martin Family Sustainability Fellow (2023).