LAUSR

Abstract In this paper, polyvinyl alcohol/SO42−-anodic aluminum oxide (PVA/SO42−-AAO) membranes, the dual-functional flat composite membranes (DCMs) applied for the simultaneous catalytic reaction and pervaporation, were fabricated via dip-coating method. Firstly, the PVA/AAO pervaporation composite membranes (SCMs) were prepared by using PVA as the active separation layer and AAO as the support layer. Secondly, the SO42− was loaded in the pores of AAO by dipping the membranes in dilute sulfuric acid solution. Thirdly the membranes were calcinated at 400 °C to produce the solid acid catalyst layer (SO42−-AAO). Finally, PVA solution was coated on one side of SO42−-AAO, and then the PVA/SO42−-AAO difunctional membranes were prepared. The effects of PVA concentration on the morphology and hydrophilicity of SCM were characterized by SEM and water contact angle. The effects of the concentration of the sulfuric acid solution on morphology, acid sites, elements distribution and crystal form of DCMs were characterized by SEM, MIP, NH3-TPD, XPS and XRD. The catalytic activity of SO42−-AAO was investigated through the esterification between ethanol and acetic acid. When the concentration of sulfuric acid was 2 mol/L, the SO42−-AAO had the best catalytic behavior. For the separation performance, compared with SCMs, the DCMs had higher flux but lower separation factor. Using DCM4 to do the pervaporation-esterification coupling experiments, acetic acid conversion reached above 96% after the 16-hours’ reaction, in addition, more than 90% acetic acid conversion was achieved after the operation of 80 h.