Fabrication and Investigation of Separation Performance and Antifouling Properties of Mixed Matrix PES-Based Nanofiltration Membrane Containing Cobalt-Ferrite Nanoparticles

Abstract

Hypothesis: Mixed matrix polyether sulfone (PES)-based membranes, containing cobalt-ferrite nanoparticles, were prepared by polymer solution casting technique through phase inversion method in water bath. Methods: The concentration effect of CoFe2O4 nanoparticles, synthesized in polymeric solution, on the morphology and separation performance was studied. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), porosity measurement, water contact angle, water flux, Na2SO4 rejection as well as membrane antifouling ability were used to characterize the membrane. Findings: The SEM images showed the movement of NPs toward water-membrane interface to reduce surface energy during the fabrication process. The SEM images also showed an asymmetric structure with a dense active layer and a porous sub-layer with finger-like channels for the prepared membranes. The use of cobalt ferrite nanoparticles in the membrane matrix decreased the water contact angle from 71° to 48°. The results of AFM images also showed a smoother surface for the prepared mixed matrix membranes compared to the bare ones, which improved the membrane antifouling property in BSA rejection. Pure water flux (PWF) was initially enhanced by incorporation of cobalt ferrite NPs and then decreased by up to 1 wt% NPs due to NPs agglomeration. Moreover, Na2SO4 salt rejection increased from 60% for the neat membrane to 80% for the modified ones with 1.0 wt% cobalt-ferrite nanoparticles. The mixed matrix membrane containing 1.0 wt% cobalt-ferrite nanoparticles showed better performance compared to others.

Keywords

• polymeric membrane
• nanofiltration
• cobalt-ferrite nanoparticles
• purity
• antifouling ability
• separation performance