Hollow mesoporous silica nanoparticles: A peculiar structure for thin film nanocomposite membranes

Abstract

Incorporation of nanomaterials into the thin film composite (TFC) membrane is a promising approach to enhance the filtration performance of the membranes. This study was aimed to fabricate a novel thin film nanocomposite (TFN) membrane hybridized with hollow mesoporous silica nanoparticles (HMSN). It was expected that the HMSN-TFN membranes could have enhanced desalination performance. The research was focused on understanding of how the HMSN incorporation could affect physicochemical properties and permeation behavior of the HMSN-TFN membranes. Spherical HMSN with an average particle size of ~70 nm were fabricated by hydrothermal synthesis using soft templates. The HMSN were successfully incorporated into the selective polyamide layer in the TFN structures. The physicochemical properties of the HMSN and TFN membranes were systematically investigated using DLS, TGA, ATR-FTIR, SEM, TEM, nitrogen sorption analyser, tensiometer and XPS analysis. The HMSN-TFN membranes were more hydrophilic and performed highly improved water flux (~40%) compared with the TFC membranes, while their rejection to NaCl was not significantly changed. The HMSN-TFN membranes also displayed a higher compaction resistance than the TFC membrane, suggesting a positive interaction between the HMSN and the polyamide thin film layer. This interaction is beneficial for enhancing the strength and durability of the newly developed HMSN-TFN membranes in the high-pressure filtration process.