Enhancing organic dye removal: Unveiling the potential of visible-light-driven photocatalytic N-CQD-modified MIL-53 (Fe) nanocomposite (NCM)/PES nanofiltration membranes

This study showcases the remarkable synergy achieved through the combination of two distinct unit operations, namely filtration and photocatalysis, in the context of removing Methyl Red (MR). The approach involves the immobilization of a visible-driven N-CQD/MIL-53 (Fe) photocatalyst (NCM) within a polyethersulfone (PES) matrix, resulting in the development of a mixed-matrix membrane. This innovative configuration is then employed within a photocatalytic membrane reactor, thereby facilitating the efficient removal of MR. In this particular instance, a combination of 0.2, 0.6, and 1.0 wt% NCM was meticulously incorporated into a casting solution based on PES. The ultimate objective was to obtain mixed-matrix membranes subsequent to the process of phase inversion. The integration of NCM nanocomposite within the membrane matrix resulted in an enhancement of the porous structure and topology of the membranes, thereby leading to an elevation in water permeability (PWF of 94.14 +/- 1.88 kg/m2. h), an enhancement in hydrophilicity (WCA of 49.7 +/- 0.99o), and a notable antifouling property (FRR of 95.76 %) of the resulting membranes. Furthermore, it is worth noting that the NCM nanocomposite possesses remarkable photocatalytic properties, granting the membrane the capacity to remove and photodegrade MR (methyl red) dye when exposed to visible light. Notably, the optimal performance of the membrane (M0.6) is observed when it successfully rejects a significant portion (89.1 %) of the MR dye. The discoveries elucidated by this study offer a plausible methodology for addressing the predicament of organic dyes present in wastewater, wherein the compounds in question are both rejected and degraded in tandem.