High performance polyacrylonitrile-supported forward osmosis membranes prepared via aromatic solvent-based interfacial polymerization

• Published in: Separation and purification technology 2019-04, Vol.212, p.449-457
• Main Authors: Kwon, Hyo-Eun, Kwon, Soon Jin, Park, Sung-Joon, Shin, Min Gyu, Park, Sang-Hee, Park, Min Sang, Park, Hosik, Lee, Jung-Hyun
• Format: Article
• Language: English
• Subjects: Desalination; Forward osmosis; Interfacial polymerization; Polyacrylonitrile; Thin film composite membrane
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2018.11.053

[Display omitted] •TFC FO membranes are fabricated using aromatic organic solvents (toluene).•An ultrathin and highly dense PA layer was formed on a hydrophilic PAN support.•The prepared membranes show FO performance exceeding commercial membranes.•This is due to high permeability and excellent selectivity of the prepared membrane.•Aromatic solvent greatly promotes MPD diffusion by increased miscibility with water. A high performance thin film composite (TFC) forward osmosis (FO) membrane was prepared using a hydrophilic polyacrylonitrile (PAN) support with a tailored structure via a newly devised, aromatic solvent (toluene)-based interfacial polymerization (TIP) technique. The use of toluene as the organic solvent promoted amine diffusion toward the organic phase and the subsequent reaction, leading to the formation of an ultrathin (highly permeable) and highly dense (highly selective) polyamide selective layer on the PAN support, which improved membrane performance. In addition, a relatively thin (∼80 μm) and finger-like porous support structure embedded with a nonwoven fabric was favorable for facilitating mass transport in the support. As a result, the TFC FO membrane prepared via TIP showed ∼2.1 times higher FO water flux and ∼68% lower specific salt flux than the membrane prepared via conventional aliphatic solvent-based interfacial polymerization (IP) in FO mode. Importantly, our TIP-assembled membrane exhibited superior FO performance over commercial and other lab-made membranes. Our strategy provides a facile solution to overcome the technical limitations of the conventional IP method by enabling the fabrication of high performance PA layers on hydrophilic supports, expanding the application spectrum of TFC membranes.