ELECTRONANOFILTRATION - A NEW PROCESS FOR ION SEPARATION

Nanofiltration (NF) is a new pressure-driven process which typically c oncerns the separation of species having a size of about 1 nanometer. Applications have been proposed in the fields of biotechnology, drinka ble water production, and brackish water treatment. As regards size ex clusion of neutral solutes, NF membranes have characteristics intermed iate between those for ultrafiltration and reverse osmosis. Most of th em also have a charge density which explains their typical use in salt solution filtration. Thus nanofilters can distinguish ionic species a ccording to their size and/or valence. This pioneering work aims to st udy the influence of an additional electric field on NF performance in the case of single or mixed ionic solutions. This is the so-called '' electronanofiltration (ENF) process,'' here experimented with using a new type of organo-inorganic membrane. Results are given in terms of f luxes, ion rejections, pH of solutions, and current densities. General trends are emphasized and discussed.