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 multiwalled 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

Dual-Modulated Polyamide Membranes Based on Vapor–Liquid Interfacial Polymerization for CO₂ Separation

Polyamide (PA) membranes show great application potential in the CO2 separation study. However, the PA membranes prepared by the traditional interfacial polymerization (IP) have a dense microstructure and a singularity of functional groups, making it difficult to exhibit both high CO2 permeance and selectivity. Herein, we report a new dual-modulation strategy by preparation method optimization and filler modification to improve the CO2 separation performance of the PA membranes. The PA membranes prepared by vapor–liquid IP have a loose microstructure, which greatly improves the gas permeance. The introduction of mono-(6-ethanediamine-6-deoxy)-beta-cyclodextrin (CD) can better loosen the PA microstructure, and the CO2-philic groups in the CD boost the CO2 selectivity by the facilitated transport effect. Ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate is further sealed into PA membranes to remedy the possible microvoids or defects and CD cavities of the membrane microstructure. The prepared membranes display excellent CO2 separation performance with CO2/H2, CO2/CH4, and CO2/N2 selectivity of 8.2, 45.5, and 116.9, as well as a CO2 permeance of about 320 GPU. The proposed strategy provides a facile and effective route to dual-modulated PA membranes for the study of CO2 separation and can be expanded to other macrocyclic molecules and ionic liquid systems