Wetting-resistant photothermal nanocomposite membranes for direct solar membrane distillation
Journal
Journal of Membrane Science
Journal Volume
620
Date Issued
2021
Author(s)
Abstract
Efficient use of solar energy for desalination is one strategy to solve the world's water scarcity issues. In this work, a dual functional, omniphobic−photothermal nanocomposite membrane was developed to achieve wetting resistance and low energy consumption in desalination by direct solar membrane distillation (DSMD). The membrane was prepared by forming a hierarchical structure of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS17) modified carbon black (CB) nanoparticles (NPs) on a polyvinylidene fluoride (PVDF) membrane surface. The fluorinated CB NPs absorbed sun light to provide localized heating for DSMD, which increased membrane flux by 25% upon simulated solar irradiation at one sun unit. The utilization efficiency of solar energy in the DSMD process, 75.4%, is more than one order of magnitude higher than the energy efficiency of the conventional direct contact membrane distillation process. Furthermore, the re-entrant structure formed by the CB NPs together with the hydrophobic FAS17 coating led to low surface energy and hence omniphobicity, increasing the contact angle of the 80 vol% ethanol-in-water from 0 to 94.2°. As a result, the dual functional membrane exhibited much higher resistance to wetting by surfactants. Whereas the pristine PVDF membrane was wetted by 0.2 mM SDS, SDS had no effect on the dual function membrane over the whole SDS concentration range tested (0.1–0.4 mM). The photothermal activity, improved thermal efficiency, and strong wetting resistance make the dual functional omniphobic−photothermal membrane an excellent membrane material for the DSMD process. © 2020
Subjects
Direct solar membrane distillation; Omniphobic membrane; Photothermal membrane; Re-entrant structure
Other Subjects
Carbon black; Contact angle; Desalination; Distillation; Distilleries; Energy efficiency; Energy utilization; Fluorine compounds; Nanocomposites; Solar energy; Wetting; Direct contact membrane distillation; Hierarchical structures; Improved thermal efficiencies; Low energy consumption; Modified carbon blacks; Nano-composite membranes; Polyvinylidene fluoride membranes; Utilization efficiency; Membranes; 1h,1h,2h,2h perfluorodecyltriethoxysilane; alcohol; carbon; carbon nanoparticle; nanocomposite; nanoparticle; perfluoro compound; polyvinylidene fluoride; surfactant; water; concentration (parameter); contact angle; desalination; direct solar membrane distillation; distillation; energy consumption; fluorination; heating; hydrophobicity; hydroxylation; membrane; membrane permeability; near infrared spectroscopy; photochemistry; priority journal; scanning electron microscopy; simulation; solar energy; solar radiation; sun; sunlight; thermal analysis; ultraviolet spectroscopy; wettability; Carbon Black; Contact Angle; Deionization; Distillation; Fluorine Compounds; Wetting
Type
journal article