Solar-Powered Water Purification

Access to clean, safe drinking water remains a challenge throughout the globe. Many water purification and filtration systems require additional energy, electricity, or resources. These challenges will only continue to intensify as the climate continues to change. To address this problem, researchers at Princeton University developed a technology called a Solar Absorber Gel that can purify water using only sunlight. 

The researchers were inspired by pufferfish, which absorb large amounts of water when a threat is imminent, but return to their original shape when the threat is gone. Similarly, the Solar Absorber Gel absorbs water at room temperature, but when it is heated, it changes shape and releases the water. They combined this heat-responsive gel with two other layers. The second layer, made of a material called polydopamine (PDA), transforms the sun’s energy into heat. This allows the device to work in a wide range of outdoor temperatures. The PDA, combined with the third layer made of alginate, filters out metals, pathogens, and other molecules from the water. 

The researchers showed that this technology can efficiently remove chemicals, oils, metals, and pathogens from the water. Since the device uses passive, gravity-based filtration, the only energy required for it to work comes from the sun. Additionally, this device is able to purify water much faster than similar existing technologies. This discovery is potentially transformative for areas of the world where access to drinking water remains a key hurdle. 

Lead author Xiaohui Xu, a Princeton Presidential Postdoctoral Research Fellow in the Department of Chemical and Biological Engineering at Princeton University. Senior author Rodney Priestley is the Pomeroy and Betty Perry Smith Professor of Chemical and Biological Engineering at Princeton. 

Managing Correspondent: Jaclyn Long

Original Article: A Bioinspired Elastic Hydrogel for Solar-Driven Water Purification

Additional Press: Low-cost solar-powered water filter removes lead, other contaminants