Superhydrophobized Polyacrylonitrile/Hierarchicall-FeOOH Nanofibrous Membrane for High-salinity Water Treatment in Membrane Distillation

Abstract

Water flux and hydrophobic durability play important roles in membrane distillation(MD) applications. Compared with the method of adsorbing nanoparticles by electrostatic adsorption, the surface roughness constructed by chemical bonding is more conducive to the performance of membrane. This paper reports a facile approach to fabricating superhydrophobic fluoroalkyl silane/polydimethylsiloxane@FeOOH@stabilized polyacrylonitrile(FAS/PDMS@FeOOH@SPAN) nanofibrous membrane(NFM) with outstanding hierarchical structures, aiming to achieve efficient and stable performance in MD. Electrospun polyacrylonitrile(PAN) membrane after peroxidation was chosen as the base membrane, followed by in-situ synthesis of iron oxyhydroxide and liquid-phase silanization. We tested the characteristics of FAS/PDMS@FeOOH@SPAN NFM in each preparation stage and its performance in direct contact membrane distillation(DCMD). The chemical bond between iron oxyhydroxide and the membrane is stronger, making the rough structure steady and dense. The FAS/PDMS@FeOOH@SPAN NFM exhibited a water contact angle of 155.4° and excellent hydrophobicity towards different pollutants. Besides, it showed satisfied properties with a water flux of 24.7 L·m−2·h−1, a high salts rejection of ca. 100% and an extended-term stability in DCMD using hypersaline water(10%, mass ratio). It is believed that this novel study proposes a universal and efficient method to fabricate a superhydrophobic surface and has great potential for high-salinity wastewater treatment in MD.