State-of-the-Art Technology to Fabricate Outstanding Thin-Film Composite Membranes

Dear Colleagues,

Thin-film composite (TFC) membranes have been incredibly developed in various high-quality membrane separation, especially in water and gas separation, to achieve higher separation efficiency and product purity. Generally, a TFC membrane is asymmetric, consisting of a very thin top selective layer (~200 to 400 nanometer in thickness) made out of highly selective polymers for the intended purposes and fabricated onto a porous support (several hundred micrometers in thickness). Usually, the porous support shows high chemical and mechanical stability in the intended membrane separation. Due to the very thin top layer, the TFC configuration is also employed to overcome several performance-related limiting factors, including the permeability-and-selectivity trade-off relationship.

For example, in water treatment for drinking water and seawater desalination, generally the asymmetric TFC is composed of a top selective polyamide (PA) layer to efficiently separate soluble ions (e.g., salts) in water, supported on a porous substrate. TFC membranes have exhibited much better performances in terms of water permeability and ion selectivity than those of first-generation symmetric membranes, such as cellulose membranes, since thin selective layers and substrates were easily tailored to enhance their membrane performance. Fast forward to today, TFC membranes are becoming one of the go-to configurations in both academia and industries for drinking water purification, wastewater reuse, and desalination. In particular, several TFC membranes developed by world-leading membrane companies such as Hydranautics and Toray chemical have been technically optimized and commercialized for membrane processes. Nevertheless, it is necessary to develop high-performance TFC membranes for lower energy consumption and less fouling propensity. Many researchers around the world have used various technical approaches, such as the incorporation or deposition of nanomaterials onto the membrane surface or into the membrane structure, surface modification, self-standing fabrication, etc., to overcome the drawbacks of current TFC membranes.

Similarly, in the field of gas separation and purification, the urgent needs for more efficient and robust membrane separations have led many membrane researchers towards the TFC configuration. The configuration, however, is still facing several inevitable challenges (e.g., layer delamination), especially the performance trade-off where the TFC configuration normally produces lower product purity. Several approaches have been presented, which include the use of additives (organic, inorganic and hybrid (e.g., metal organic framework) fillers) in the top selective layer for its enhanced performance. Nevertheless, there are still many arising issues related to its ‘sophisticated’ fabrication that need to be addressed and investigated.

This Special Issue aims to provide an academic platform that allows authors to share state-of-the-art TFC fabrication technologies and their findings. The topics covered include, but are not limited to, all the academic or technical aspects related to fabricating outstanding TFC membranes and their modulations. We welcome all interested authors to submit your original research articles, reviews, and perspectives under the topic.

Kind regards,
Dr. Sungil Lim
Dr. Mohd Zamidi Ahmad
Guest Editors

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• thin-film composite membrane
• thin-film nanocomposite membrane
• surface modification
• self-standing membrane
• interfacial polymerization
• polyamide
• water treatment
• desalination