From flat-sheet to hollow-fiber theophylline-imprinted membranes

The technological progress of the modern society as well as the necessity of recovery and recycling precious resources allowed the development of more and more efficient and sustainable separation materials. In this perspective, a relevant contribution comes from the employment of membrane-based separation systems. In particular, the production of imprinted membranes offers the possibility of achieving high separation level of targeted compounds. Some example of applications are the selective separation of ions and toxic substances from wastewaters and the recovery of bioactive compounds from food matrices or other sources1,2. This work deals with the development of imprinted polymeric membranes for the selective recovery of theophylline (THEO) from water samples containing also the structural analogue caffeine (CAFF). Theophylline is a xanthine used in the cure of asthma, chronic obstructive pulmonary disease and chronic bronchospasm3,4. Firstly, flats-sheets imprinted membranes were prepared via the non-solvent induced phase inversion technique by dispersing different amounts of a pre-synthesized imprinted polymer in a modified poly(ether ether ketone) (PEEK-WC) polymer solution. Molecular recognition investigations carried out in aqueous environment permitted to assess the specific recognition properties of the imprinted membranes with respect to the simple (PEEK-WC)-based membranes and the non-imprinted membranes prepared under the same operating conditions. Starting from these results, the phase inversion technique was also applied for producing novel hybrid hollow-fiber imprinted membranes containing the 5% of THEO-imprinted polymer with respect to the (PEEK-WC). Membranes were prepared at two different composition of bore fluid and using water as the non-solvent.