Pervaporation dehydration of acetic acid using polyelectrolytes complex (PEC)/11-phosphotungstic acid hydrate (PW11) hybrid membrane (PEC/PW11)

Novel polyelectrolytes complex (PEC)/11-phosphotungstic acid hydrate (PW11) hybrid membranes (PEC/PW11) were prepared by blending sodium alginate (SA) and gelatin (GE), followed by incorporating with PW11, and then crosslinking by γ-Glycidoxypropyltrimethoxysilane (GPTEOS). Structures of the membranes were characterized by X-ray diffraction (XRD), FT-IR, thermogravimetry (TG), scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle goniometer methods. The characterization results demonstrated that the amorphous regions in the membrane and hydrophilicity of the membrane enhance with increasing PW11 content; thermal stability of the membrane strengthened with the introducing of PW11; PW11 was homogeneously dispersed in the PEC matrix when PW11 content was no higher than 9 wt%. Swelling experiments showed that the degree of swelling (DS) of the PEC/PW11 hybrid membranes increased with increasing PW11 content or water content in feed. Sorption experiments demonstrated that when PW11 was no more than 9 wt%, both the sorption selectivity and diffusion selectivity increase with increasing PW11 content, then decrease with further increasing PW11 content. PEC/PW11 hybrid membrane containing 9 wt% PW11 exhibited the best pervaporation performance, whose averaged permeation flux was 0.440 kg/m2/h and separation factor was 144 for 90 wt% aqueous solution of acetic acid at 50 °C.