New separation hybrid membrane cells applied to ultrafiltration processes

摘要

Membrane separation processes, such as macromolecules separation by ultrafiltration, have been intensively used in diverse fields as food industry and biotechnology. Several techniques have been explored to increase the efficiency of the separation of two macromolecules by ultrafiltration, which is strongly affected by concentration polarization of the layer over the membrane surface. Several methods have been proposed in the literature to reduce this concentration polarization, such as: Dean vortices [1], oscillatory flows [2], flow enhanced by Taylor bubbles [3], turbulence promoters [4] and backflushing [5]. Hybrid Membrane Cell (HMC) is a new type of membrane cell that was conceptualized in our research group (CEFT), having in mind similar effects. The starting point was the separation of one solute from its solvent through a HMC [6] - cell with two types of membranes, i.e. different porosities, alternating in juxtaposition along the cell; semi-permeable membranes only permeable to the solvent and fully permeable membranes permeable to the solute and to the solvent - Figure 1. With this configuration of the hybrid cell, it was observed a reduction of the concentration polarization phenomena and an increase of the separation [6].