Comprehensive Analysis of Spinel-Type Mixed Metal Oxide-Functionalized Polysulfone Membranes toward Fouling Resistance and Dye and Natural Organic Matter Removal.

Nanostructured polymeric membranes are of great importance in enhancing the antifouling properties during water filtration. Nanomaterials with tunable size, morphology and composition, surface modification, and increased functionality provide considerable opportunities for effective wastewater treatment. Thus, in this work, an attempt has been made to use spinel-structured MnCo2O4 as a nanofiller in the fabrication of nanostructured polysulfone (PSF) mixed matrix membranes and is investigated in terms of morphology, hydrophilicity, permeability, protein and natural organic matter separation, dye removal, and, finally, antifouling properties. The MnCo2O4 nanomaterials are synthesized and characterized via X-ray diffraction and field emission scanning electron microscopy and are loaded into a membrane matrix with varied concentrations (0 to 1.5 wt %). PSF nanocomposite membranes are prepared via a nonsolvent-induced phase-separation process. The results show an enhancement in hydrophilicity, porosity, and permeability with respect to the modified nanocomposite membranes because of oxygen-rich species in the membrane matrix, which increases affinity toward water. It was also found that the modified membranes display remarkably greater pure water flux (PWF) (220 L/m2 h), higher Congo red rejection coefficient (99.86%), higher humic acid removal (99.81%), higher fouling resistance, and a significant flux recovery ratio (FRR) (88%) when tested with bovine serum albumin protein when compared to a bare PSF membrane (30 L/m2 h PWF and 35% FRR). This is because the addition of MnCo2O4 nanoparticles into the polymeric casting solution yielded tighter PSF membranes with a denser skin layer and greater selectivity. Thus, the enhanced permeability, greater rejection coefficient, and antifouling properties show the promising potential of the fabricated PSF-spinel nanostructured membrane to be utilized in membrane technology for wastewater treatment.

Nitrogenated Graphene Oxide-Decorated Metal Sulfides for Better Antifouling and Dye Removal.

Nitrogenated graphene oxide-decorated copper sulfide nanocomposites (Cu x S-NrGO, where x = 1 and 2) are designed to be incorporated in polysulfone (PSF) membranes for effective fouling resistance of PSF membranes and their dye removal capacity. The developed membranes possess more hydrophilicity and an enhancement in pure water flux (PWF). Also, the highest bovine serum albumin (BSA) rejection of 89% was observed when compared to membranes with pristine PSF (5 L/m2 h PWF and 88% BSA rejection) and CuS-incorporated PSF membranes (14 L/m2 h PWF and 83% BSA rejection) because of N doping and enhanced permeability. It is also found that the Cu x S-NrGO-incorporated PSF membranes exhibited a significantly higher fouling resistance, a larger permeate flux recovery ratio (FRR) of nearly 82%, and a congo red dye rejection of 93%. Cu x S-NrGO nanoparticles thus demonstrate the potential efficacy of enhancing the hydrophilicity, leading to a better flux, dye removal capacity, and antifouling capacity with a very high FRR value of 82% because of a strong interaction between the N-active sites of the NrGO, Cu x S, and polysulfone matrix, and negligible leaching of nanoparticles is observed.