Pusan National University Study Advances Solar Desalination with Multifunctional Membrane

Researchers develop an innovative membrane technology to sustainably address challenges associated with desalination

BUSAN, South Korea, July 31, 2026 /PRNewswire/ -- As the world's population grows and industry expands, many countries in Africa, the Middle East, and Southeast Asia are facing a freshwater scarcity crisis. Finding sustainable ways to produce clean water has become an urgent priority, and solar desalination may be one of the most promising routes available. By using sunlight to evaporate and purify seawater, this technology could serve as an efficient source of freshwater in areas facing water shortages.

However, seawater contains more than just salt. Coastal waters near ports and industrial areas are often contaminated with oil, which can clog the specialized membranes used in desalination systems. Although many experimental desalination platforms have shown promising results, most have been tested using clean saltwater under laboratory conditions. Thus, it remains unclear how well they would actually perform with real-world seawater.

To address this challenge, a research team led by Professor Sanghyun Jeong from the Department of Civil and Environmental Engineering, Pusan National University, Republic of Korea, has developed a new multifunctional hydrogel membrane for solar-driven desalination. Their study was made available online on June 1, 2026, and will be published in Volume 636 of the journal Desalination on October 15, 2026. Rather than treating oil separation and desalination as separate processes, the researchers designed a single membrane architecture that does both.

The proposed membrane has a 'Janus' architecture, meaning it has two sides with different properties. One side is water-attracting (hydrophilic) and made from a chitosan and polyvinyl alcohol hydrogel; it lets water through while repelling oil droplets. The other side is water-repelling (hydrophobic) and contains copper oxide nanoparticles wrapped in a carbon shell, embedded in a nanofiber layer. This side absorbs sunlight, converts it into heat, and drives water evaporation at its surface. Because each layer focuses on one task, oil rejection and heat generation do not interfere with each other, which can happen in single-layer designs.

Experiments revealed that the proposed membrane removed over 99.99% of oil from contaminated seawater while maintaining stable performance against different oil droplet sizes and repeated use. During solar desalination, it achieved an evaporation rate of 1.29 kilograms of water per square meter per hour, which is nearly three times higher than that of a conventional single-layer membrane. "By harnessing renewable solar energy and integrating contaminant separation with freshwater production in a single membrane platform, our technology has the potential to reduce energy consumption, operational complexity, and secondary waste generation, contributing to more sustainable water treatment and freshwater production," says Prof. Jeong.

The researchers believe that the membrane developed in this study highlights a broader design strategy for future water treatment technologies, as Prof. Jeong explains, "Beyond the specific application of desalination, the broader significance of this work lies in demonstrating how multiple treatment functions can be rationally integrated within a single membrane architecture." Such multifunctional systems could help make solar-powered water treatment more practical for contaminated coastal waters and industrial wastewater, while also supporting efforts to recover useful resources from concentrated brines.

Further research in this field will hopefully lead to a future in which freshwater is easily accessible everywhere in the world.

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SOURCE Pusan National University