Nano-Filtration Performance and Temperature Dependency of Thin Film Composite Polyamide Membranes Embedded with Thermal Responsive Zwitterionic Nanocapsules

Abstract

Incorporating thermal responsive nano fillers is a promising strategy to input thermal responsiveness into thin film nanocomposite (TFN) polyamide NF membranes. Thermal responsive structurally controllable zwitterionic nanocapsules (ZN C s) were embedded in the polyamide (PA) active layers to form ultra fast thermal responsive water transporting channels for high flux thermal responsive nano filtration performance. The loading level, diameter, crosslinker ratio, and core/shell ratio of ZN C s affected not only the structure and nano-filtration (NF) performance, but also the thermal responsive sensitivity of TFN membranes. ZN C s with the diameter of 100-110 nm, crosslinker ratio of 50 wt% and core/shell ratio of 3:1, at the loading level of 0.01% w/v in aqueous phase possess highest flux change slope of 6.24 L·m -2 ·h -1 /°C (LMHC), 8.7 times higher than that of control thin film composite (TFC) NF membranes. The water flux of ZN C s -TFN membrane could increase from 57 L·m -2 ·h -1 (LMH) to 88 LMH at 0.6 MPa from 25 °C to 30 °C without losing salt rejection rates.

Keywords: Zwitterionic, Nanocapsules, Nanofiltration, Thermal-responsive