Functionalized iron oxide nanocomposite ultrafiltration membranes for water-in-oil emulsion separation
Removal of emulsified water in oil (w/o) emulsions are the most challenging compared to free water and dissolved water emulsions. Emulsified w/o cannot be removed by conventional techniques such as settling tanks, oil skimmers, floatation and magnetic technologies. Membrane technology is a highly efficient, energy saving, and pollutant free alternative. In this work, iron oxide-oleylamine nanoparticles have been synthesized and embedded into polylactic acid (PLA) to make a hydrophobic-super-oleophilic ultrafiltration membrane. The concentration of the nanoparticles was varied from 0.5 to 3% of the polymer. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), and Fourier-transform infrared radiation (FTIR) were utilized to confirm both the attachment of the oleylamine on the iron oxide and the loading of the prepared nanoparticles into the PLA membrane. The water contact angle was found to increase steadily as the concentration of the nanocomposites increased. This was associated with the hydrophobicity of the membranes, allowing the oil to penetrate through the membrane. Moisture removal in surfactant‐stabilized w/o emulsions reached up to 80% in the composite membranes, compared to only 52% in the pristine PLA. The maximum permeability was found to be at 2% loading, where 885 L/m2.h/bar was reported, compared to 500 L/m2.h/bar in the PLA. The abundance of iron-oxide, and the biodegradability of PLA prove the capability of the prepared membranes to be a viable and environmentally friendly alternative for w/o separation.