Membrane characterization of modified polyvinylidene fluoride and polyphenol concentration by nanofiltration

Identifier:  TFG:1179

Handle: https://hdl.handle.net/20.500.11797/TFG1179

Authors:  Aguilar Rodríguez, Elisabeth

Abstract:
RESUM Membrane technology is presently an established part of several industrial processes. Nanofiltration membranes, with properties in between those of ultrafiltration and reverse osmosis, have come a long way since it was first introduced during the late 80’s 1. In literature, the determination of structural properties of a nanofiltration membrane based on its separation performance and its industrial applications are widely studied. For this reason, the goal of this Project is the characterization of some modified polyvinylidene fluoride membranes and the concentration of two different polyphenols, phenols and flavonoids, using the nanofiltration technique. For the characterization of PVDF membranes different techniques have been evaluated. Based on the static techniques, which mainly give information on membrane morphology and structure as well as chemical and physical properties, Environmental Scanning Electron Microscopy and Contact Angle techniques have been used in order to study these different properties. As for dynamic techniques, Nanofiltration has been used for the purpose of performing permeability test of modified PVDF membranes by layer-by-layer deposition with ethanol and isopropanol as solvents. Membrane technology is an option that allows to concentrate at low temperatures. That is why, this technique has been used for polyphenols due to it is a compound that degraded in high temperature. Thus, nanofiltration has been carried out with ethanolic and isopropanolic extracts. Each extract has been carried on through two distinct fractions: permeate and retentate. The capacity of the membrane to retain the compounds has been verified by spectrophotometric analysis. These techniques used both for the characterization of PVDF membranes and the determination of the concentration of phenols and flavonoids have been accomplished. However, the result obtained during the experimental for concentrating polyphenols compounds has not been satisfactory.