Facilitated transport of cations (copper, silver, zinc) by solid dense membranes

For the removal of heavy metals, such as copper, zinc and silver from industrial effluents specific membranes have been developed containing carriers that are capable to transport these ions at a high rate by a facilitated transport mechanism. The carriers(crown ethers)are coupled to a polymer resulting in a fixed carrier membrane. We investigated the transport of silver, copper and zinc ions by sulfonated polisulfone and polyether ether ketone membranes modifies with crown-ether.