Solar desalination makes fresh water with no brine, Rochester team reports

A solar desalination method developed at the University of Rochester produces fresh water from seawater without chemical pre-treatment and, instead of dumping concentrated brine back into the sea, recovers almost all of the leftover salts as solids. The university described the system on 27 May 2026, in a study published in the journal “Light: Science & Applications” by a team led by Chunlei Guo, a professor of optics and physics and senior scientist at Rochester’s Laboratory for Laser Energetics.

The same panels can be tuned to pull out specific minerals. In a companion paper in the “Journal of Materials Chemistry A”, the group reports extracting about 50% of the lithium from the salts left behind, using water samples from the Great Salt Lake.

How the brine-free solar desalination method works

Common desalination methods such as reverse osmosis and thermal distillation are energy-intensive, need water treatment before and after, and leave a concentrated saltwater byproduct, brine. Returned to the sea, brine raises salinity and lowers oxygen, harming marine life. The United Nations estimates 2.2 billion people lack safely managed drinking water, and coastal regions increasingly rely on desalination to close the gap — pressure set out in the Winss Solutions overview of how the world is heading towards a major water crisis.

Guo’s system uses panels of black metal textured with femtosecond lasers so the surface both absorbs nearly all incoming sunlight and pulls water across itself, a property called superwicking. A laser-treated active region draws a thin film of water along the panel, the absorbed solar heat distils it, and the leftover salts and minerals are pushed to the untreated passive region at the edges. The study, titled “Additive-free and brine-discharge-free solar-thermal desalination with simultaneous complete mineral mining from ocean water”, was tested on water from the Pacific, Atlantic, and Indian Oceans.

The result is a surface that cleans itself: it kept distilling fresh water while steering the salts aside, rather than clogging as many solar stills do when tested on real seawater. Guo likens the salt-steering to the “coffee ring” effect, where a drying coffee drop leaves its particles in a ring at the edge.

Turning brine into salts, salt into lithium

The method’s main departure from conventional desalination is what happens to the salt. Rather than leaving brine to dispose of, it recovers close to 100% of the salts in solid form. Those solids can yield table salt and, with a further tweak, critical minerals: by embedding hydrogen titanate nanoparticles in the panel’s grooves, the team separated lithium from the other salts, recovering about 50% of it from Great Salt Lake samples. Lithium is the key metal in the batteries used in electric vehicles and electronics. “Pulling lithium directly from saltwater could be a very important future route,” Guo said, noting that mining it from rock is taxing on energy and the environment.

How the approach lines up against today’s standard methods is set out below.

Source: University of Rochester; Guo et al., “Light: Science & Applications” and “Journal of Materials Chemistry A”, 2026.

The work is at the proof-of-concept stage on small devices, and the team has not yet reported fresh-water output rates, energy-conversion efficiency, or cost for a full-scale plant. Guo describes the technology as inherently scalable. The research was supported by the National Science Foundation, the Bill & Melinda Gates Foundation, and the Worldwide Universities Network.

About Chunlei Guo’s laser-materials work at Rochester

The University of Rochester’s Institute of Optics, founded in 1929, was the first US academic department dedicated to optics and has awarded a large share of the country’s optics degrees. Chunlei Guo’s laboratory there is known for using femtosecond lasers to texture metal surfaces at the micro- and nanoscale, giving them properties such as extreme water attraction or repulsion and near-total light absorption. The group has applied the same “black metal” platform to solar steam generation and to boosting solar power output. This desalination result extends that line of work to two linked problems at once — water scarcity and the demand for battery minerals — and points toward solar-powered systems that produce drinking water while keeping useful materials in circulation rather than discharging them, a direction that fits the wider shift mapped in the future of green energy.

Sources: Light: Science & Applications; University of Rochester; Journal of Materials Chemistry A; ScienceDaily

Featured image: photo by Deane Bayas on Pexels (free Pexels license).

Become a Sponsor

Our website is the heart of the mission of WINSS – it’s where we share updates, publish research, highlight community impact, and connect with supporters around the world. To keep this essential platform running, updated, and accessible, we rely on the generosity of you, who believe in our work.

We offer the option to sponsor monthly, or just once choosing the amount of your choice. If you run a company, please contact us via info@winssolutions.org.

• donate monthly
• donate once only

Select a Donation Option (USD)

$5.00 (p/m) $10.00 (p/m) $20.00 (p/m) Other (p/m)

Enter Donation Amount (USD)

Figen Sekin

I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.