Full Breakdown
University of Rochester Introduces Solar-Thermal Desalination System Without Brine
5/27/2026, 7:52:37 PM
Breakthrough Solar-Thermal Desalination System
Researchers at the University of Rochester have built a solar-thermal desalination device that converts seawater to drinking water using sunlight. Black metal panels etched with femtosecond lasers form a super-light-absorbing, superwicking surface that evaporates a water film; the vapor condenses as fresh water while salts are directed to a passive zone.
Global Water Need and Conventional Desalination Drawbacks
The United Nations estimates 2.2 billion people lack safely managed drinking water. Existing coastal plants use reverse-osmosis or thermal distillation, consume large electricity, require chemical pretreatment, and discharge concentrated brine that depletes oxygen and harms marine life.
Research Team and Funding
Professor Chunlei Guo (optics and physics) leads the project with senior scientist Subash Singh, alumnus Ran Wei ’24, PhD candidates Luheng Tang and Tainshu Xu, and researcher Mingjiang Ma. Funding is provided by the National Science Foundation, the Bill & Melinda Gates Foundation, and the Worldwide Universities Network.
Technical Approach and Performance
Laser-etched grooves prevent clogging by calcium- and magnesium-based scales. The coffee-ring effect drives evaporating salts outward into a passive zone, keeping the active area clear. Tests with Pacific, Atlantic and Indian Ocean water yielded continuous fresh water at stable efficiency. The system captures nearly 100 % of salts as solid residue; a companion study embedded hydrogen-titanate nanoparticles in the grooves to extract about 50 % of lithium from residues derived from Great Salt Lake water.
Environmental and Economic Implications
Eliminating liquid brine removes a major source of marine pollution. The solid salt byproduct can supply table salt and offers a low-energy route to obtain lithium—a critical battery material—without traditional mining. Researchers describe the system as inherently scalable, potentially expanding global drinking-water access and supporting sustainable mineral supply chains.
Official Statements & Responses
Professor Guo said the method uses the coffee-ring principle to move salts to a passive region, ensuring self-cleaning operation. He noted that mining lithium from the earth is energy-intensive, making direct extraction from saltwater a potentially important route. Funding agencies emphasized the project’s alignment with water-security and environmental goals.
Verbatim Quotes
- “If you drop coffee on a surface, eventually the water evaporates, and there’s a ring left at the outer edge that is the concentrated coffee particles,” — Chunlei Guo, Professor of Optics and Physics
- “We use that same principle to advance the salts to the passive region.” — Chunlei Guo, Professor of Optics and Physics
- “Mining lithium from the earth has proven to be very taxing from an energy and environmental standpoint, so pulling lithium directly from saltwater could be a very important future route,” — Chunlei Guo, Professor of Optics and Physics
What’s Next
The team will scale the prototype, run field trials in coastal communities, and refine lithium-selective nanoparticle integration. Industry partnerships are planned to assess commercial viability and integration with existing water-treatment infrastructure.
