Fouling-Resistant Microfiltration Membrane Modified with Magnetite Nanoparticles by Reversible Conjunction
Seung Taek Woo, Taeseon Yun, Seung-Yeop Kwak
Index: 10.1016/j.seppur.2018.04.002
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Abstract
We developed a stimuli-responsive poly(tetrafluoroethylene) (PTFE) microfiltration (MF) membrane by reversible conjunction of magnetite nanoparticles. We modified the magnetic particles with maleimide functional groups and attached them to a furan-modified PTFE membrane via a Diels–Alder (DA) cycloaddition reaction to prepare an anti-fouling membrane that responds to magnetism and temperature. The combined results of Fourier-transform infrared spectroscopy, X-ray diffractometry, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy investigations clearly showed that the maleimide-modified magnetic nanoparticles were successfully synthesized and coupled with the furan-modified PTFE MF membrane by the DA reaction. The modified membrane produced a micro-vortex under a rotating magnetic field, and showed a high resistance to fouling with a water flux higher than 50% of initial flux even after 30 minutes in the fouling test, whereas the neat membrane had a water flux falling below 20% of initial flux in 30 min. Moreover, the magnetite nanoparticles were readily and repeatedly regenerated on the MF membrane surface using a thermally driven peel-and-stick process; 75% of the water flux was recovered, even after three fouling cycles.