Manipulation of homogeneous membranes with nano-sized spherical polyelectrolyte complexes for enhanced pervaporation performances in isopropanol dehydration

Abstract

Spherical polyelectrolyte complexes (PECs) sized at 10–20 nm were synthesized to fabricate homogeneous polyelectrolyte complex membranes (HPECMs). The PEC dispersions at various concentrations were employed to manipulate the thickness of HPECMs. Zeta potentials were measured to quantify the charge density of PECs. Scanning electron microscopy was utilized to examine membrane morphology and thickness. The surface hydrophilicity of HPECMs was evaluated by using static water contact angles. Being subjected to isopropanol dehydration, the synthesized HPECMs with nano-sized spherical PECs exhibited excellent separation performance, good stability and durability. The HPECM with the thickness of 1.1 μm displayed a significantly high permeation flux (6.12 kg m–2 h−1) with an ideal water concentration in permeate (99.85 wt%). The use of nano-sized spherical PECs ensured the homogeneous nature of synthesized polyelectrolyte complex membranes, leading to the enhancement of pervaporation performances in isopropanol dehydration. The extension of this work would trigger a large-scale application of HPECMs for dehydration of organic solvents.