Surface Modification of PVDF Membrane with a Caffeic Acid-Imprinted Polymer Layer

Resumen

Combination of imprinting and membrane technology allowed to prepare molecularly imprinted membrane having great potential application in molecular separation and purification on the valuable herbal extraction. This technology offers the advantage of combining the mechanical integrity of the membrane support with the selective recognition properties of the imprinted polymer layer. The purpose of this work was to prepare a highly specific molecular imprinted membrane (MIM) towards extraction of caffeic acid by surface modification of microfiltration polyvinyldine floride (PVDF) with a thin layer of molecular imprinted polymer. The imprinted membranes were fabricated utilizing caffeic acid as the template, 4-Vinylpyridine (4-VP) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker via thermal polymerization process. Blank imprinted membranes were prepared with the same monomer and cross-linker composition but in the absence of the template. The imprinted membranes were characterized through the Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) to prove that the polymerization process successfully prepared on the surface of the PVDF membranes. The molecular imprinted membrane (MIM) showed the thicker fibrous membrane structure compare to the non-imprinted membrane (NIM). The binding performance indicated that the MIM obtained the highest caffeic acid adsorption of 0.22 mg/g at concentration of 12 mg/L. MIM also have higher selectivity towards caffeic acid compared to other structural analogues. The imprinted membrane prepared in this work could be applied as new separation devices in affinity filtration aimed to extract caffeic acid content in raw herbal materials.