Preparation and characterization of the organic–inorganic hybrid membrane for biodiesel production

A novel organic–inorganic hybrid membrane as heterogeneous acid catalyst for biodiesel production was prepared from zirconium sulfate (Zr(SO4)2) and sulfonated poly(vinyl alcohol) (SPVA). The structure and properties of the hybrid catalytic membrane were investigated by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetry (TG), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic performance of the hybrid membranes was tested by the esterification of the acidified oil with methanol. It was found that the Zr(SO4)2 particles were better dispersed in SPVA matrix as a result of the stronger interaction between Zr(SO4)2 and SPVA compared with Zr(SO4)2/poly(vinyl alcohol) (PVA) hybrid membrane. Esterification results showed that the conversions of free fatty acid (FFA) in acidified oil were 94.5% and 81.2% for Zr(SO4)2/SPVA and Zr(SO4)2/PVA catalytic membranes, respectively. The stability of Zr(SO4)2/SPVA catalytic membrane is superior to Zr(SO4)2/PVA catalytic membrane.