Water molecules are everywhere, from the atmosphere around us to the technologies that power our modern world. Yet extracting this moisture from the atmosphere in an efficient way remains a significant challenge. In a major breakthrough using Gadi, researchers have discovered a way to dramatically enhance atmospheric water capture using a smart combination of graphene oxide and calcium ions.
A recent study, led by the labs of Professor Rakesh Joshi (University of New South Wales), Nobel Laureate Professor Sir Kostya Novoselov (National University of Singapore), and Professor Amir Karton (University of New England), uncovered how the interaction between calcium ions and the oxygen-containing functional groups on graphene oxide (GO) creates a synergistic effect, enhancing water uptake by over threefold compared to the materials used alone. These findings not only deepen our understanding of molecular water interactions at material surfaces but also pave the way for future technologies that can harvest clean water directly from the air.
How Does It Work?
Water molecules interact in complex ways at the boundary between solids and liquids, a region vital to many natural and industrial processes. In this study, researchers explored how functionalised carbon surfaces like graphene oxide interact with hydrated calcium ions to form stronger hydrogen-bond networks.
When calcium ions are embedded into the porous structure of graphene oxide (GO) aerogels, the resulting material (Ca-GOA) captures far more water than either component alone. Remarkably, each calcium atom in Ca-GOA attracted over three times more water molecules than in its pure form, revealing a powerful synergy between calcium and graphene oxide.
This enhanced performance stems from interfacial polarisation, which is the buildup of electric charges at material boundaries, strengthening hydrogen bonding. Probing this mechanism required a combination of experimental work and advanced atomic-scale simulations.
The Power of Gadi: NCI’s Supercomputer Behind the Science
To understand the molecular mechanism underlying the exceptional water-capturing ability of Ca-GOA, the research team relied on the power of NCI’s Gadi supercomputer. Professor Amir Karton at the University of New England led the computational work, performing large-scale density functional theory (DFT) simulations to model the interactions between calcium ions, GO, and water molecules. These DFT calculations were vital for explaining experimental observations. The advanced simulations run on Gadi revealed the source of the synergy: the interactions between the oxygen atoms of graphene oxide and the calcium ions dramatically strengthen the hydrogen-bond network, increasing the material's water uptake far beyond the sum of its parts. This fundamental insight provides a molecular-level understanding, enabling the design of even more effective materials for harvesting clean water from the atmosphere.
Why NCI Matters
NCI’s supercomputing capabilities enable cutting-edge research like this, which opens exciting possibilities for sustainable water solutions. As demand grows for energy-efficient atmospheric water harvesting, the study offers a promising alternative for arid and remote areas. The enhanced material could power next-generation technologies like AWH (Atmospheric Water Harvesting) systems, energy-saving dehumidifiers, and even eco-friendly air conditioning.
Beyond water capture, this research exemplifies how NCI’s infrastructure accelerates scientific breakthroughs across biology, chemistry, and environmental science by enabling detailed study of hydrogen-bond networks in natural and engineered systems.
Please find the paper here: https://doi.org/10.1073/pnas.2508208122
A simulation from Gadi reveals the source of the synergy. The interaction between the GO oxygens and the hydrated calcium ion (center) dramatically strengthens the hydrogen-bond network with surrounding water molecules, enhancing the material's water-capturing ability.
Professors Rakesh Joshi (University of New South Wales), Nobel Laureate Sir Kostya Novoselov (National University of Singapore), and Amir Karton (University of New England).