Researchers have developed an innovative membrane that not only purifies saltwater using solar energy but also generates electricity—offering a promising solution for off-grid communities facing water scarcity and energy challenges.
The membrane, made from zwitterionic fibrous materials, is designed for interfacial solar steam generation (ISSG), a process that uses photothermal conversion to evaporate water at the air–liquid interface. Unlike traditional desalination systems, this membrane resists salt buildup, maintains stable evaporation rates, and exhibits antibacterial properties, making it suitable for long-term use in harsh environments.
What sets this system apart is its integration with a thermoelectric module. As the membrane absorbs solar heat to evaporate water, the residual thermal energy is converted into electricity. This dual-function setup enables the device to produce clean water and power simultaneously—ideal for remote or coastal areas with limited infrastructure.
The membrane’s design draws inspiration from biological systems that regulate ion transport. It uses polyacrylonitrile (PAN) as a substrate and incorporates porphyrin-based polymers to enhance solar absorption and antibacterial performance. Zwitterionic polyionic liquids (PILs) embedded in the membrane help prevent salt accumulation by attracting sodium and chloride ions and redistributing them, ensuring consistent water flow even under high salinity conditions.
In performance tests, the membrane achieved an evaporation rate of 2.64 kg/m²/h and a photothermal efficiency of 97.6% under standard solar irradiation. When paired with the thermoelectric module, it delivered a power density of 1.5 W/m²—enough to run small electronic devices.
This breakthrough points toward scalable, decentralised systems that can address two critical global challenges: access to clean water and renewable energy. While still in the research phase, the technology could pave the way for compact, low-maintenance solutions that reduce environmental impact and infrastructure costs.
(Source: Electropages)