Unlocking the Potential of Networked Cellulose for the Enhanced Nanofiltration Performance of TFC Membranes

Thin-film composite (TFC) membranes have been widely employed for desalination and water treatment to achieve superior separation performance. TFC membranes having a thin active polyamide (PA) selective layer supported by a highly porous support layer have been demonstrated to provide enhanced permeability maintaining excellent salt rejection. Several modifications have been introduced in the TFC layers to advance their membrane performance further. This study proposes incorporating networked cellulose (NC) in the aqueous layer leading to a wrinkled polyamide selective layer with improved filtration area and hydrophilicity rendering significantly enhanced membrane permeance. The less explored NC with highly networked interconnected cellulose fibers was incorporated into the separation layer by simply dispersing in the Piperazine (PIP) solution followed by interfacial polymerization with 1,3,5-Benzenetricarbonyl trichloride (TMC). The TFC membrane with optimum NC loading provided a pure water permeance of 19.12 ± 1.7 Lm^-2h^-1bar^-1 (remarkably higher than pristine TFC with 7.2 ± 0.46 Lm^-2h^-1bar^-1) while maintaining MgSO₄ and Na₂SO₄ rejection above 90%. This study successfully demonstrated the potential use of NC as a low-cost and nontoxic filler to improve the performance of polyamide nanofiltration membranes for water desalination.