Generating electricity from wastewater

The purification of various water resources, from rainwater to wastewater, is a high-energy process. So, what if electricity could actually be generated during the process? A research team has developed a multifunctional membrane that can simultaneously generate electricity while purifying wastewater into drinking water.

Scientists from the Korea Institute of Science and Technology’s (KIST) Electronic Materials Research Centre and Myongji University’s Department of Materials Science and Engineering have partnered to develop an advanced membrane that can simultaneously provide drinking water and generate continuous electricity from various water resources, such as sewerage/wastewater, seawater and groundwater.

The “sandwich-like” membrane comprises a porous membrane that filters water at the bottom and a conductive polymer that generates electricity at the top. It is designed to purify wastewater by controlling the direction of the water flow. Water flowing perpendicularly to the membrane generates direct current by the movement of ions along the horizontal direction. The membrane can reject more than 95% of the contaminants of sizes less than 10 nm (one hundred-millionth of a metre). Hence, microplastics and heavy metal particles in wastewater can be removed, and continuous electricity can be generated for more than 3 h with only 10 µl (microlitres) of water.

The membrane has a high potential to be commercialised as it can be manufactured using a simple printing process without size restrictions. The research team is currently conducting follow-up research to generate electricity while improving the water quality of wastewater to the level of drinking water by developing the membrane for an actual factory.

“As a novel technology that can solve water shortage problem and produce ecofriendly energy simultaneously, it also has great potential applications in the water quality management system and emergency power system,” said Dr. Ji-Soo Jang from KIST.

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