As the use of membrane technology for gas separation has grown, various membrane materials have been developed by numerous researchers to demonstrate separation processes. The present study was intended to make a novel thin film nanocomposite (TFN) membrane hybridized with amino functionalized acid-activated bentonite (ABn-NH) clay. It was projected that the ABn-NH-TFN membranes could improve water vapor permeation performance. The present work was done paying attention to how the incorporation of ABn-NH could affect the TFN membrane physicochemical properties and permeation performance. Thin films of ABn-NH-TFN membranes were prepared using interfacial polymerization on the inner surface of a polysulfone (PSf) hollow-fiber membrane support for the separation of a water vapor/N₂ gas mixture. The prepared material and thin film composite membranes were fully characterized using physicochemical techniques including X-ray diffraction, BET surface analysis, thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle analysis. The concentration effect of ABn-NH clay (0–1.0 wt%) on the permeation of water vapor and N₂ was investigated. According to SEM images of the composite membranes, 0.5 wt% of ABn-NH clay particles shows good dispersion on a thin selective layer. Water vapor permeation results showed that with the incorporation of ABn-NH particles into the polyamide membrane, the permeance increases enormously. The most advantageous performance, that of ABn-NH-TFN-3 (0.5 wt%) membrane, was achieved with a water vapor permeance of 2809 GPU and a water vapor/N₂ selectivity of 913, with a membrane prepared with 2.0 wt% MPD and 0.2 wt% TMC monomer concentrations of coating solution.

In this study, we report the synthesis of thin film nanocomposite (TFN) membranes by interfacial polymerization (IP) on porous polysulfone (PSf) hollow fiber membrane supports. We also investigate the synthesis of carboxylated TiO₂ (C-TiO₂) and hydroxylated TiO₂ (H-TiO₂) nanoparticles using a simple technique and evaluate the performance of the TFN membranes incorporated with these nanoparticles for water vapor separation. Comparative studies were carried out on membranes with and without the incorporation of nanoparticles (TFN and TFC) for water vapor separation. Aqueous 3,5-diaminobenzoic acid (DABA)/nanoparticles mixture solutions and organic trimesoyl chloride (TMC) were used in the IP process. The reaction between these two monomer solutions at the interfaces of PSf hollow fiber substrates resulted in the formation of the TFN membranes. Functionalized TiO₂ nanoparticles (TiO₂NPs) with a size of about 60 nm were used for the fabrication of the TFN hollow fiber membranes. These TFN membranes were characterized using different modern techniques and evaluated in comparison with the tidy TFC membranes. Their performances were evaluated based on the water vapor permeability and selectivity. Experimental results indicate that the carboxylated TiO₂ nanoparticle (C-TiO₂NPs) incorporated membrane shows improved performance compared to other membranes. By changing the nanoparticles, better hydrophilicity was obtained; the contact angle was decreased from 90° (PSf) to 46° (TFN) and the water vapor permeance was increased from 780 GPU (TFC) to 1131 GPU (TFN) with high selectivity being maintained (from 115 to 548) when the C-TiO₂NPs content was 0.05 (wt%).

In the present study, thin film composite membranes have been prepared using an interfacial polymerization method. First, we coated a polydopamine (PDA) layer using different concentrations of PDA solution on polyethersulfone (PES) hollow fiber supports. After the PDA coating layer, thin film composite (TFC) membranes were prepared with 3,5-diaminobenzoic acid (3,5-DABA) as an aqueous phase monomer and trimesoyl chloride (TMC) as an organic phase monomer to synthesize a hydrophilic polyamide layer. This prepared selective layer is considered desirable to fabricate hydrophilic TFC membranes for water vapor/N₂ separation. The TFC membranes by interfacial polymerization were confirmed and discussed using the accumulated results of characterization. Hollow fiber membranes (HFM) surface modification with PDA before TFC coatings was proposed to modestly and effectively enhance the membrane selectivity. The newly prepared TFC hollow fiber membranes acquired reasonably excellent selectivity and superior permeation fluxes. As a result, membrane sample MS4 coated with 2.0 wt% PDA and TFC prepared using 0.5 wt% of 3,5-DABA with 0.2 wt% of TMC and 60 s of reaction time showed the best permeance and selectivity as 3185 GPU and 195, respectively, compared with other TFC membranes prepared with different PDA concentrations. Overall, the membranes showed good performance in the entire range of operating conditions investigated.

In this work, 3,5-diaminobenzoic acid (BA) was selected to synthesize polyamide as a selective layer because it is considered desirable to fabricate hydrophilic thin film composite (TFC) membranes for water vapor separation.