MOF-based photothermal Janus membrane with robust anti-fouling performance for enhanced membrane distillation

As a promising desalination technology, photothermal membrane distillation (PMD) is confronted with challenges such as low freshwater yield and membrane fouling. Herein, we have introduced a copper-based metal- organic framework (Cu-CAT) into a hydrophilic/superhydrophobic polyvinylidene fluoride (PVDF) Janus treelike nanofiber membrane (TLNMs) to construct photothermal Janus TLNMs (P-Janus TLNMs) for enhanced PMD. Given the exceptional photothermal properties of the hydrophilic Cu-CAT layer, coupled with the fine pore structure and elevated porosity characteristics of the superhydrophobic PVDF TLNMs, P-Janus TLNMs have demonstrated outstanding performance when integrated into a PMD system. Upon exposure to solar illumination of 1 kW center dot m(-2), the P-Janus TLNMs achieved a remarkable surface temperature of 88 degrees C, yielding a permeation flux of 1.46 L m(-2) h(-1), a salt rejection rate exceeding 99.99 %, and an energy utilization rate of 81 %. Furthermore, after 20 days of continuous operation with simulated seawater containing oil and surfactant, the P-Janus TLNMs presented a salt rejection of 99.9 % and a stable permeation flux of 1.71 L m(-2) h(-1) at the feed/permeate temperatures of 24/20 degrees C. This work introduces a novel membrane with immense potential for boosting permeation flux and enhancing anti-fouling properties in PMD, thereby advancing the frontier of sustainable seawater desalination.