Preparation and characterization of phosphotungstic acid/PVA nanofiber composite catalytic membranes via electrospinning for biodiesel production

A nanofiber composite catalytic membrane for biodiesel production was prepared from phosphotungstic acid (PWA)/poly(vinyl alcohol) (PVA) via electrospinning on a substrate of non-woven fabric. The effects on the nanofiber structure and catalytic performance by PVA concentration and PWA content were studied, respectively. SEM images showed that the surface of PWA/PVA nanofibers was smooth and homogeneous with an average fiber diameter of 157.2 nm when PVA concentration was 12 wt% and PWA content was 20 wt%. FTIR analysis indicated that there existed the interaction between PWA and PVA in the nanofibers. DSC and TG analysis revealed that PWA/PVA nanofiber had a good thermal stability. The nanofiber membrane had a higher activity and better site accessibility than that of commercially ion-exchange resin (NKC-9) because both reaction rate constant (2.647 min−1) and effectiveness factor (0.92 min−1) of nanofiber membrane were higher than that of NKC-9. The stability test of nanofiber membrane suggested that the conversion could remain stable for 10 days in a continuous flow-through reactor for biodiesel production.