2018 Volume 16 Issue 1 Pages 63-71
Synthesis of magnetic nanoparticles (MNPs) attracted the interest of many researchers for many applications. Among the applications of interest is their potential use as a draw solution in forward osmosis owing to their ease of recovery and surface-area-to-volume ratio. Such a draw solution is expected to generate high osmotic pressure. However, for such an application, the choice of coating material is a crucial parameter which is still poorly understood. In this paper, we tested three different coating materials with different properties (molecular weight and hydrophobicity) to better understand their effect on the properties (ability to generate flux, dispersion, magnetic properties, recovery, etc.) of coated MNPs. Magnetic nanoparticles were prepared using co-precipitation method. Various coating materials were used in this study, namely dextran 40,000, oleic acid and polyethylene glycol 2,000 and 4,000. Magnetite co-precipitation and nanoparticle coating were carried out simultaneously. The coated nanoparticles were characterized using scanning electron microscope, X-ray Powder Diffraction, coating ratio, and osmotic pressure and flux generation. Findings indicate that in order to suppress aggregation and generate osmotic pressure, coating material should have low molecular weight and feature a hydrophilic property.