Solar-Intensified Ultrafiltration System Based on Porous Photothermal Membrane for Efficient Water Treatment

Membrane separation is widely regarded as a promising technology for water treatment. To run the membrane at the optimal conditions, preheating of feedwater before being sent into the membrane unit is often employed, which results in high energy consumption. Here we report a multifunctional system that combines traditional pressure-driven membrane filtration with solar thermal technology based on a photothermal membrane for high-efficiency water treatment. The multifunctional membrane consists of multi-walled carbon nanotubes and polysulfone (MWCNT-PSf), which not only facilitates the water permeation through the membrane but also effectively heats the feed solution by sustainable solar energy. The composite membrane containing MWCNT demonstrates excellent light absorption of 94% over the full solar spectrum range, which can effectively preheat the feedwater. With the assistance of light irradiation, the MWCNT-PSf photothermal membrane exhibits high water flux over 314 L m(-2) h(-1) with a rejection above 95% for coomassie brilliant blue at 0.10 MPa, which is 101.3% higher than that without light irradiation. The solar-intensified ultrafiltration system based on a porous photothermal membrane provides a new avenue to treat wastewater or seawater.