Studies On Pervaporation Separation Of Multiple Organic Compounds From Aqueous Solution By PEBAX Composite Membrane

In order to alleviate the pollution of transfer pringting wastewater to environment, this research aimed at the separation of organics, including ethanol, butanone, isopropyl alcohol (IPA), propylene glycol monomethyl ether (PGME), from the wastewater of transfer pringting, polyether block amide (PEBAX2533) was chosen as a pervaporation (PV) membrane material for removal of the organics from the wastewater by pervaporation. Bentonite was modified by Hexadecyl trimethyl ammonium bromide (CTAB) and nano silicon dioxide (n-SiO2) as a filling materials for improving the separation properties of membranes, filled membranes and filled-composite membranes were prepared, respectively. The morphology features and crystalline nature of membrane were characterized by SEM, XRD and FTIR, respectively. It can be seen that the filled-composite membrane was dense with no appreciable voids and the particles dispersed uniformly in the membrane. Separation layer and supporting layer combined together tight from the images of SEM. The result of XRD and FTIR showed that the filler is only physically blended with the polymer matrix without chemical actions. Through the swelling experiment in binary of ethanol/water, butanone/water, IPA/water, PGME/water as well as quinary system of organic s/water, it can be found that membrane has a good swelling capacity for the systems of ethanol/water, butanone/water, IPA/water. In addition, the degree of swelling (DS) is associated with filling amount of the particle, the DS of membrane increased as the increasing of operation temperature yet. The result of effect of particle content on the PV performance showed that the filling can improve the PV performance. The best result was obtained when CTAB-modified bentonite content in the membrane was 15wt%, maximum separation factor and permeation flux of butanone were 28.5 and 2.79 kg·m-2·h-1, respectively. The membrane with n-SiO2 0.12 wt%, the pervaporation performance was best, maximum separation factor and permeation flux of butanone were 39.4 and 3.28 kg·m-2·h-1, respectively. As to the PV research of quinary system containing four kinds of organic, due to the interaction of molecules between different-organics, the result was not as good as binary system. The best enrichment factor was 3.02 and the flux was 10.9 kg·m-2·h-1.Using the above membranes separate organic compounds from aqueous solutions via pervaporation, the results showed the filled-composite membrane has better separating property to ethanol, butanone, IPA; but the result of separating to PGME was unsatisfactory. The result of nano silicon dioxide filled-composited membrane was better than that of the CTAB modified bentonite filled-composited membrane.