(123b) Preparation of Mesoporous Silica Nanoparticles Enhanced Thin-Film Nanocomposite (TFN) Membrane for Water Purification

A thin-film nanocomposite (TFN) membrane containing mesoporous silica nanoparticles (NPs) was prepared by the in situ interfacial polymerization (IP) process. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. Mesoporous silica NPs (~100 nm) and non-porous spherical silica NPs (~100 nm) were synthesized and used as the fillers to fabricate the TFN membrane at concentrations ranging from 0 to 0.1 wt.%. The membranes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy, and their performances were evaluated based on the pure water permeability and salt rejection. Results indicated that the mesoporous silica NPs dispersed well in polyamide (PA) thin-film layer and improved membrane performances under optimal concentrations. By increasing its concentration, hydrophilicity, roughness and zeta potential of TFN membranes all increased. Notably, the pure water flux increased around 64% with the incorporation of mesoporous NPs, while maintaining high rejections of NaCl and Na₂SO₄ (over 97% and 98%, respectively). When compared with membranes containing non-porous NPs, the membranes containing mesoporous NPs showed enhanced permeability, suggesting that the short flow paths through the hydrophilic porous structure of mesoporous NPs had played an important role in water permeation.