Fabrication, characterization, and performance study of acriflavine TFC nanofiltration membrane for brine concentration

A novel thin-film composite (TFC) membrane is prepared by coating titanium dioxide (TiO2) nanoparticle-incorporated acriflavine and trimesoyl chloride (TMC) on polysulfone (PSf) substrate with the aim of enhancing the permeation and salt rejection properties of PSf membrane. The membrane characterization was performed using Fourier transform infrared (FT-IR), atomic force microscope, field emission scanning electron microscope, and contact angle (CA) goniometer. The FT-IR spectral studies confirmed the interfacial polymerization of acriflavine and TMC. The study also confirmed the effective incorporation of TiO2 nanoparticles, and the addition of TiO2 nanoparticle in acriflavine TFC active layer improved the morphology of the membrane and CA. In terms of water flux, the TFC membrane with 0.1 wt.% TiO2 nanoparticle content achieved water flux of 67.1 L m–2h–1 against deionized water and 53 and 44.5 L m–2h–1 against Arabian Gulf seawater and reverse osmosis brine, respectively, when tested using dead-end filtration. The acriflavine TFC membranes showed excellent antifouling characteristics when the loading of TiO2 was 0.1 wt.% with >99% rejection for magnesium (Mg2+), calcium (Ca2+), and sulfate (SO42–) ions. Overall, this study demonstrated the potential of using acriflavine as an amine monomer for the fabrication of polyamide layer with increased membrane performance toward seawater pretreatment and brine concentration applications.