Chitosan- and dehydroascorbic acid-coated Fe3O4 nanoparticles: preparation, characterization and their potential as draw solute in forward osmosis process

Abstract

Forward osmosis (FO) is a natural osmosis process that has attracted a significant attention due to its many advantages. However, the development of FO process depends on the development of proper draw solutions. In this work, chitosan (CS)-coated Fe3O4 nanoparticles and dehydroascorbic acid (DHAA)-coated Fe3O4 nanoparticles were successfully synthesized by co-precipitation method and their performance as draw solutes was investigated for application in FO systems. CS and DHAA could improve the surface hydrophilicity of the Fe3O4 nanoparticles. The synthesized nanoparticles were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometry (VSM) which the results presented a small size, crystalline morphology and high magnetization value for their structure as well as a good dispersion in water. Cellulose triacetate/cellulose acetate (CTA/CA)-based membranes were also prepared by immersion precipitation and used as FO membranes. The synthesized FO membranes were characterized by FESEM. The performance evaluation of synthesized nanoparticles revealed that the water flux of Fe3O4 nanoparticles capped with DHAA was higher than that of the chitosan-coated Fe3O4 nanoparticles. At the end of the process, the Fe3O4 nanoparticles were easily separated from the diluted draw solution by applying the magnetic field.