Reduction of microbial contamination from drinking water using an iron oxide nanoparticle-impregnated ultrafiltration mixed matrix membrane: preparation, characterization and antimicrobial properties

Abstract

Iron oxide nanoparticles were prepared and mixed in polyacrylonitrile to produce an ultrafiltration flat sheet mixed matrix membrane with high flux and adequate antimicrobial properties. Membranes with a molecular weight cut-off in the range of 48 to 65 kDa were obtained by varying the concentration of iron oxide nanoparticles. The cast membranes were characterized by scanning electron microscopy, permeability, molecular weight cut-off, contact angle, porosity, pore size distribution, surface area and mechanical strength. The antibacterial activity of the iron oxide nanoparticles on Escherichia coli was explored and confirmed by using confocal microscopy and scanning electron microscopy. The efficacy of the mixed matrix membrane to remove the total microorganisms and coliforms was analyzed using tap water. Adsorption of microorganisms (Escherichia coli) on the mixed matrix membrane was quantified. A minimum dose of 0.4 wt% of iron oxide nanoparticles completely inhibited the growth of microorganisms. Effects of operating conditions, namely transmembrane pressure and cross flow rate, on the system performance were also investigated.