Optimization of Al2O3/PES membranes for wastewater filtration

In this study, polyethersulfone (PES) ultrafiltration membranes were casted and modified by dispersing nano-sized alumina (Al2O3) particles uniformly in a PES solution (18% polymer weight). Membranes with 5 different weight ratios of Al2O3 to PES of 0.01, 0.03, 0.05, 0.1, and 0.2 were examined. Ultrafiltration experiments compared water flux and molecular weight cut-offs (MWCO) for the wet membranes. The effects of the nanometer Al2O3-particles concentration in the polymer dope on the permeation properties, membrane strength, and anti-fouling performance were examined using activated sludge. The membrane matrix was characterized using scanning electron microscope (SEM). Al2O3 entrapped membranes showed lower flux decline compared to neat polymeric membranes. Fouling mitigation initially increased with nanoparticle content and stabilized thereafter. The optimum load of Al2O3 immobilized membranes for MBR application in terms of highest membrane permeability and lowest fouling rate was the 5% weight fraction of Al2O3 with PES.