Investigation of pervaporation hybrid polyvinylchloride membranes for the separation of toluene-n-heptane mixtures - case of clays as filler

The transport properties of hybrid membranes based on polyvinylchloride (PVC) was studied for the separation of Toluene-n-Heptane mixtures by pervaporation (PV). Aromatic-alkane mixtures are difficult to fractionate by conventional processes and PV has already been shown as a promising technology in this case. PVC was chosen as starting material in this study because it gathers two key advantages: firstly, it is a technical polymer which is readily available, conversely to speciality polymers often developed for membrane application; secondly, PVC is a polar polymer endowed with a good affinity for aromatic solvents. Thus mixed matrix PVC membranes were studied to determine if it was possible to obtain interesting separation properties from this simple and cheap polymer. We report the results obtained with several types of clay used as fillers to get hybrid PVC membranes. Hence, PVC based mixed matrix membranes were prepared with Maghnite H, Maghnite H+ Wyoming, Kaolin and Nanocor clay particles. It was found that the PVC transport properties could be drastically modified both by the amount and by the type of clay incorporated. According to the fillers incorporated in the polymer matrix, it was shown that the transport properties could be easily tuned either as barrier materials or as Toluene selective membranes with strongly enhanced flux compared to initial PVC membranes.