Sorption and diffusivity study of acetic acid and water in polymeric membranes

In this work, acetic acid dehydration using lab-scale polymeric membranes was studied. Polyphenylsulphone (PPSU) based membranes were used as a barrier to selectively transport water molecules through the membrane matrix. It was observed that PPSU membranes swelled significantly when the acetic acid concentration is increased in the feed solution. Further analysis was carried out by performing a surface sorption analysis using Fourier transform infrared (FTIR) followed by pervaporation (PV) separation of acetic acid and water. The effect of the feed concentration and temperature on diffusivity and permeability was studied and the partition coefficient for each PPSU membranes was obtained. From the results, it was observed that water established strong hydrogen bonds with the membrane surface, which consequently allowed a faster sorption and diffusion of water molecules. In addition, a plasticizing effect resulted in increased water permeation, leading to a higher separation factor. These results explain why, when the acetic acid feed concentration is increased, the flux decreases and the separation factor increases.

► PPSU membranes have been utilized for dehydration of acetic acid.
► Correlation between swelling of membrane and feed concentration has been evaluated.
► Sorption of PPSU membranes were investigated using FTIR.
► Partition coefficient was determined and feed/membrane/permeate relationship was established.