Regenerable Antifouling Reverse Osmosis Membrane with Electro-Responsive Hydrophilic Complex

Abstract

We developed electro-responsive thin film composite polyamide reverse osmosis (RO) membrane with regeneration property and anti-fouling property by introduction hydrophilic modified ferrocene (Fc)-cyclodextrin (CD) complex. Modified RO membrane can be regenerated by attaching and detaching the cyclodextrin with electrical treatment. First, we prepared branched Polyethylenimine modified with ferrocene (b-Fc). Various composition of b-Fc was synthesized to optimize the performance. A commercial thin film composite polyamide RO membrane was improved with b-Fc using carboxyl group function by carbodiimide-induced grafting. Then, Cyclodextrin and ferrocene were combined with the introduction of cyclodextrin. Successful synthesis of b-Fc was observed by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR). Furthermore, successful preparation of electro-responsive hydrophilic complex-modified RO membrane was confirmed by attenuated total reflectance Fourier transform infrared (ATR FT-IR) and X-ray spectroscopy (XPS) analysis. Also, Field emission scanning electron microscopy (FE-SEM), atomic force microscope (AFM), and water contact angle measurement were additionally implemented to define the surface property of the membrane surface. Finally, filtration tests were conducted to evaluate the water flux, NaCl rejection, anti-fouling property, and recovery performance. As expected, the modified membrane showed high antifouling property and the water flux of modified membrane could be recovered to 86.4% after electrical treatment. Therefore, we demonstrated that regenerable membrane exhibiting high recovery from fouling was successfully developed.