Faced with the global challenge of freshwater scarcity, researchers in Singapore have turned to solar steam generators (SSGs) as a promising solution for seawater desalination. While desalination traditionally demands significant energy and cost, this innovative approach harnesses renewable solar energy to mimic the natural water cycle, evaporating and isolating water.
A key limitation of existing technology is the necessity for complex topologies to increase surface area, essential for achieving high water evaporation efficiency. To address this, the research team drew inspiration from nature, specifically trees, and employed advanced 3D printing techniques.
In a study published in Applied Physics Reviews, the team introduced a cutting-edge technology to produce highly efficient SSGs for desalination. They also unveiled a novel method for printing functional nanocomposites using multi-jet fusion (MJF).
“We created SSGs with exceptional photothermal performance and self-cleaning properties,” stated Kun Zhou, a professor of mechanical engineering at Nanyang Technological University. “Using a treelike porous structure significantly enhances water evaporation rates and ensures continuous operation by preventing salt accumulation—its performance remains relatively stable even after prolonged testing.”
The innovative design leverages light-to-thermal energy conversion. The SSGs absorb solar energy, convert it to heat, and evaporate seawater. Their porous structure aids in self-cleaning by removing accumulated salt, ensuring sustained desalination performance.
“By using an effective photothermal fusing agent, MJF printing technology can rapidly create parts with intricate designs,” Zhou explained. “To improve the photothermal conversion efficiency of fusing agents and printed parts, we developed a novel type of fusing agent derived from metal-organic frameworks.”
Inspired by plant transpiration, the SSGs feature miniature tree-shaped microstructures that form an efficient, heat-distributing forest. This bio-inspired design significantly increases the surface area of the SSG, enhancing water transport and boosting evaporation efficiency.
Field trials and simulated environments revealed a remarkably high rate of water evaporation. The desalinated water consistently met drinking water standards, even after prolonged testing.
“This demonstrates the practicality and efficiency of our approach,” Zhou said. “And it can be quickly and easily mass-produced via MJF commercial printers.”
The team’s work holds significant promise for addressing freshwater scarcity. “Our SSGs can be used in regions with limited access to freshwater to provide a sustainable and efficient desalination solution,” Zhou noted. “Beyond desalination, it can be adapted for other applications requiring efficient solar energy conversion and water purification.”
This breakthrough represents a significant step forward in sustainable water management, offering a viable solution to one of the world’s most pressing challenges.
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