Bio-inspired Fabrication of Ultrafiltration Membranes incorporating Polydopamine Functionalized Graphene Oxide Nanoparticles

Novel PSF composite UF membranes incorporating low loadings of polydopamine-functionalized graphene oxide particles (rGO-PDA) were fabricated and investigated. The functionalization was confirmed using FTIR-UATR, Raman spectra, XPS, and SEM. Pristine PSF, PSF/GO, and PSF/rGO-PDA MMMs were then prepared using the phase inversion technique and analyzed using FTIR, SEM, AFM, and contact angle (CA). The cross-section SEM images showed better distribution of rGO-PDA particles in the pores and polymer wall whereas the pristine GO particles aggregate and partially block the pores. Thus, the pure water flux increased with the addition of rGO-PDA without affecting the rejection properties, while the flux decreased with the embedding of pristine GO particles. The highest pure water permeability (PWP) was obtained with PSF/rGO-PDA-0.1 to be approximately twice that of the pristine PSF and PSF/GO-0.1. All membranes exhibited complete rejection of BSA and HA, and showed almost similar performance against different dyes. The FRRs of the pristine PSF after three fouling cycles (FRR3) against BSA and HA were recorded to be 57.8% and 70.7% respectively. FRR3 was enhanced by around 30% with PSF/rGO-PDA composites. The MMMs prepared in this work are expected to have great potential on ultrafiltration and similar studies on other membrane processes.