Fabrication and identification of polysulfone/Fe3O4@APTES nanocomposite membranes used in membrane bioreactors for oily wastewater treatment†

In this study, nanocomposite membranes were fabricated and characterized for use in membrane bioreactors (MBRs) to treat oily wastewater. Iron oxide nanoparticles (Fe₃O₄) were first synthesized and then modified by tetraethoxysilane (TEOS) and 3-aminopropyl triethoxysilane (APTES). The membranes were prepared by adding Fe₃O₄@APTES at different concentrations of 0, 0.05, 0.1, and 0.3 wt%, which were denoted by different codes of TFC, TFN-0.05, TFN-0.1, and TFN-0.3, respectively. The highest water flux through the membrane without Fe₃O₄@APTES nanoparticles (TFC) was recorded as 58.36 L m⁻² h⁻¹, which was later reduced to 46.80 L m⁻² h⁻¹ by adding nanoparticles to the membrane (TFN-0.3). The TFN-0.1 membrane demonstrated the best membrane bioreactor performance. The final concentration of heavy metals by the MBR system with the TFN-0.1 membrane was 84.96% Pb(II) > 80.18% Zn(II) > 74.43% Cr(III) > 74.14% Ni(II). Hence, it was found that adding Fe₃O₄@APTES nanoparticles to the membranes could reduce irreversible fouling. The results showed that the TFN-0.1 membrane with a flux recovery ratio of 96.3% had the most optimal antifouling performance among the other nanocomposite membranes.