Nanocomposite desalination membranes made of aromatic polyamide with cellulose nanofibers: synthesis, performance, and water diffusion study
Rodolfo Cruz‐Silva, Kazuo Izu, Jun Maeda, Shigeru Saito, Aaron Morelos‐Gómez, Celia Aguilar, Y. Takizawa, Ayaka Yamanaka, Syogo Tejiima, Kazunori Fujisawa, Kenji Takeuchi, Takuya Hayashi, Tōru Noguchi, Akira Isogai, Morinobu Endo
Abstract
Reverse osmosis membranes of aromatic polyamide (PA) reinforced with a crystalline cellulose nanofiber (CNF) were synthesized and their desalination performance was studied. Comparison with plain PA membranes shows that the addition of CNF reduced the matrix mobility resulting in a molecularly stiffer membrane because of the attractive forces between the surface of the CNFs and the PA matrix. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy results showed complex formation between the carboxy groups of the CNF surface and the m- phenylenediamine monomer in the CNF-PA composite. Molecular dynamics simulations showed that the CNF-PA had higher hydrophilicity which was key for the higher water permeability of the synthesized nanocomposite membrane. The CNF-PA reverse osmosis nanocomposite membranes also showed enhanced antifouling performance and improved chlorine resistance. Therefore, CNF shows great potential as a nanoreinforcing material towards the preparation of nanocomposite aromatic PA membranes with longer operation lifetime due to its antifouling and chlorine resistance properties.