Pervaporation with Ceramic-Supported Polymer Membranes

This project has focused on the development, characterization and demonstration of the application of novel ceramic-supported polymer (CSP) membranes for the selective separation of organics from aqueous systems. These CSP membranes are fabricated by modifying the pore surface of ceramic membranes via the process of graft polymerization, which results in a layer of terminally anchored polymer chains covering the surface of the membrane pores. The resultant CSP membrane is a composite structure in which the mechanical strength is provided by the ceramic support and the selectivity is determined by the behavior of the polymer brush layer. Through the selection of the appropriate polymer for the desired separation task, the grafted polymer surface layer will be synthesized to impart specific separation properties to the membrane. In this project tubular ceramic-polyvinyl acetate (PVAc) grafted membrane was developed for pervaporation removal of volatile chlorinated hydrocarbons from aqueous systems. A pervaporation system was designed and built with on-line GC analysis. Future work on pervaporation will also be extended to the evaluation of the ceramic-PVP membrane for alcohol dehydration given that the recent published studies have suggested that PVP would be an ideal polymer for such a task. The CSP membrane development work has been guided by a detailed evaluation of polymer-solute affinity. This part of the project involves an experimental study of solute adsorption in a packed column. For this purpose a fully automated adsorption/regeneration column system was built. We have shown that the polymeric phases can be easily regenerated with aliphatic alcohols and thus have demonstrated that, if needed, the CSP membranes can be easily freed of any adsorbed solute. This part of the study is now being extended to evaluate the partitioning of organic solutes to polymeric phases which are terminally anchored onto silica resins. This work, coupled with a theoretical study of polymer/solute partitioning will increase our understanding of the performance of the grafted polymer phases in CSP membrane operations.