Synthesis of magnetite in poly(vinyl alcohol) matrix and its use in separation of acetone/water mixtures via pervaporation, vapor permeation with and without temperature difference methods

• Synthesizing in situ nanoparticles of Fe3O4 in PVA matrix.
• In situ preparation of nanofiller reinforced membranes.
• Improvement of stability of PVA membranes in aqueous solutions without crosslinking.
• The highest separation factor of 14000 was achieved for TDVP method.

In this paper, poly (vinyl alcohol) (PVA) magnetite (Fe3O4) nanocomposite membranes were prepared and used for the separation of acetone/water mixtures via pervaporation (PV), vapor permeation (VP) with and without temperature difference (TDVP) methods. Various PVA membranes having 10–25 wt.% in situ synthesized magnetite nanoparticles were prepared and the resultant nanocomposite membranes characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Contact angles were measured for the description of the surface hydrophilicity of the membranes. Detailed studies were carried out for the investigation of the effects of membrane thickness (20–40 μm), operating temperature (30–50 °C), feed composition (0–100 wt.%) and magnetite content (10–25 wt.%) on the separation performance. The optimum membrane thickness, magnetite percentage, operating temperature and feed composition were determined as 35 μm, 20 wt.%, 40 °C and 20 wt.%, respectively, for PV. Permeation fluxes in VP and TDVP were found to be lower than that of PV, however, the highest separation factors were obtained in TDVP method. Fe containing PVA polymer matrix showed high separation factors but slightly decreased permeation flux, compared to pristine PVA polymer membranes. Depending on the operation conditions and the method the permeation fluxes and separation factors were found to be in the range of 0.015–0.091 kg/m2 h and 29.1–14,000, respectively. In addition sorption and diffusion properties of the magnetite containing PVA membranes were investigated at different operating temperatures. It was observed that the sorption selectivity was dominant factor in the separation of acetone/water mixtures.