Enhancing Water Desalination and Dye Removal Efficiency through the Integration of a Functionalized Carbon Nanotube Intermediate Layer in Polyamide Thin-Film Nanofibrous Composite Membranes

Abstract

The trade-off between permeability and selectivity of the conventional type of thin-film composite (TFC) reverse osmosis (RO) membranes is known as one of the critical issues that has caused many concerns during the last decade. The introduction of an interlayer onto the porous substrates in TFC membranes before the interfacial polymerization (IP) process has been defined as an effective technique that enhances the TFC membranes’ performance and breaks the trade-off between permeability and selectivity of common TFC membranes. Few studies have been conducted in recent years investigating multiple types of materials that have been applied as an interlayer in TFC membranes. In this case, multiwalled carbon nanotubes (MWCNTs) were used to prepare interlayer-based TFC membranes with both excellent water permeability and salt selectivity. The TFC membranes containing functionalized CNT nanoparticles (NPs) as an interlayer lead to the construction of a thin, smooth, and crumpled selective layer, which improves the TFC membranes’ permeation performance. The water permeability of CNT interlayer-based TFC membranes was reported at about 11.88 L m−2 h−1, which is 2.85 times greater than common TFC membranes without an interlayer. Also, due to the superior crosslinking degree of these interlayer-based PA TFC membranes, they show excellent rejection of various salts compared to other RO membranes.