From Oil-Contaminated Seawater to Drinking Water: Professor Woosung Kwon's Team Develops Solar-Powered "Janus Membrane"
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- Writer 커뮤니케이션팀
- 보도일자 2026-06-12
(From left) Professor Woosung Kwon and Researcher Sejeong Seo, Department of Chemical and Biological Engineering.
A research team led by Professor Woosung Kwon of the Department of Chemical and Biological Engineering has developed a high-efficiency membrane technology that uses solar energy to transform oil-contaminated seawater into clean drinking water. The technology is drawing attention as a next-generation water resource solution capable of simultaneously addressing the global water shortage crisis and marine pollution.
At the heart of this research is the development of an asymmetric "Janus hydrogel membrane" that performs both oil–water separation and solar-driven seawater desalination at the same time.
According to the research team, conventional desalination technologies based on solar-driven interfacial evaporation have been hailed as a next-generation approach for being environmentally friendly and energy-efficient. However, when applied to real-world oil-mixed seawater or industrial wastewater, oil droplets tend to clog the membrane's pores or salt crystals accumulate on the surface, reducing water evaporation efficiency.
The team overcame this challenge with an asymmetric membrane whose two sides have different properties—much like Janus, the two-faced Roman god. The bottom layer, which contacts the water, was designed with a hydrophilic hydrogel (CS-PVA) that blocks more than 99.99% of oil penetration while allowing only clean water to pass upward.
The top layer, which is exposed to sunlight, was composed of a hydrophobic polymer and copper oxide nanoparticles encased in a nitrogen-doped carbon shell (CuO@NC-PVDF). This upper layer serves a photothermal function—absorbing sunlight to generate heat—while also preventing the moisture rising from below from penetrating deep into the membrane, thereby concentrating thermal energy at the surface. This structure enables water to be rapidly evaporated into vapor.
The membrane developed by the team reached a surface temperature of up to 45°C under 1-sun conditions and up to 72°C in a dry state. Its evaporation rate of 1.29 kg/m² per hour was 2.8 times higher than that of conventional single-function membranes, and it achieved an outstanding solar-to-vapor conversion efficiency of 86.4%.
The membrane also proved durable and cost-effective. In repeated processing of oil-mixed seawater collected from coastal areas, no salt crystals accumulated on the surface and performance did not degrade. Unlike conventional single-use membranes, it can be reused, reducing operating costs by approximately 4.7 times.
Professor Woosung Kwon said, "This research is a remarkable achievement of convergence research that simultaneously solves the two greatest challenges of solar desalination systems—oil contamination and salt crystallization—through an innovative 'Janus structure.' Having proven its performance and stability even in contaminated environments, the technology is expected to find broad applications in sustainable drinking water supply and industrial wastewater treatment systems."
This study was conducted jointly with the research team of Professor Sanghyun Jung at the Institute of Environment and Energy at Pusan National University. The findings were published in Desalination (IF = 9.8, JCR top 3% in Water Resources), a world-leading journal in the field of water resources and seawater desalination, in Issue 636 (2026). The research was supported by the Mid-Career Researcher Program and the Nano and Material Technology Development Program funded by the Ministry of Science and ICT and the National Research Foundation of Korea. The first authors were researcher Sejeong Seo of the Department of Chemical and Biological Engineering at Sookmyung Women's University and researchers Siyoung Byun and Jiha Sim of Pusan National University. The corresponding authors were Professor Woosung Kwon of the Department of Chemical and Biological Engineering at Sookmyung Women's University and Professor Sanghyun Jung of Pusan National University.