(682b) Supported Liquid Membrane Permeation with Composite Membranes

Due to membrane bleeding and hence membrane break through liquid membrane permeation with support layers has not reached industrial scale yet. To overcome membrane bleeding and to increase membrane stability composite membranes have been investigated. The test membranes are fabricated of sintered polyethylene according to the design principle shown in Figure 1. Figure 1: sketch of the composite membrane The central membrane layer has a smaller pore size (7-12 µm) than the cover layers (with pore size of either 10 ? 20 µm, 18 ? 40 µm or 25 ? 45 µm). Different capillary force of the central layer and the outside layer is expected to stabilize the liquid membrane in the central membrane body. Besides different pore size and pore size distribution membranes of hydrophilic or hydrophobic surface properties were tested. Several combinations of hydrophilic and hydrophobic membrane surface properties were studied. Mass transfer was investigated with the test system for reactive extraction Zn2+|DEHPA|H+. Mass transfer of composite membranes with hydrophilic cover membranes is seemingly better. due to different wettability of hydrophilic and hydrophobic surfaces with the liquid membrane. Large pore size distribution of the cover membranes results in better mass transfer too. Investigation of membrane stability has been subject of ongoing tests. Within 600 hours of operation membrane break through has not been observed.