Networked cellulose-integrated highly permeable TFC polyamide membranes with tailored nanofiltration performance

Thin-film composite (TFC) membranes typically consist of a thin active polyamide layer atop a highly porous support layer, offering both enhanced permeability and excellent salt rejection. In this study, we propose the incorporation of networked cellulose (NC) into the aqueous layer leading to changes in the morphology, hydrophilicity, and surface charge, thereby significantly boosting membrane permeance and resistance to chlorine attack. The relatively unexplored NC, distinguished by its interconnected cellulosic fibrous structures, is introduced into the selective layer, resulting in a customized nanofiltration performance that varies depending on the concentration of NC. The fabricated TFC membranes, incorporating NC at a concentration of 0.01 % in the aqueous phase, exhibit a permeance of 19.1 ± 1.8 LMH bar^-1 combined with excellent rejection (>90 %) for divalent salts, a remarkable improvement over pristine TFC membranes which offered 7.2 ± 0.5 LMH bar^-1. Conversely, higher loading of NC (0.02 %) during fabrication results in highly permeable membranes up to 38.7 ±%3.1 LMH bar^-1 maintaining exceptional dye rejection properties. Furthermore, our findings indicate enhanced resistance to chlorine attack, highlighting the versatility of NC incorporation in the selective layer. This study underscores the scope of NC as a cost-effective and environmentally benign additive for enhancing the performance of polyamide TFC nanofiltration membranes in water treatment and desalination applications.