Application of Flotation for the Separation of Metal‐Loaded Resins#

Abstract

The separation of two typical Lewatit‐type ion exchange resins (TP208 and TP260) was studied by the application of flotation, following their preliminary use for ion exchange of zinc, a common heavy metal found in many wastewater streams. The major examined parameters were the specific type of resin and the respective ion exchange capacity, the required resin concentration for the efficient removal of metal, the influence of wetting on both processes (i.e., ion exchange and flotation), the effect of pH value on the removal of metal and on the regeneration of resin, the type and concentration of used surfactant (primary amine or quaternary ammonium were examined), as well as the effect of frother (ethanol) on flotation efficiency. The regeneration of resins was studied, with respect to the desorption of metal and to the elution of surfactant. The efficiency of combined process, which includes the removal of Zn(II) by ion exchange and the application of flotation for the subsequent solid/liquid separation of metal‐loaded resin, showed that almost 100% of zinc was removed and more than 95% of used resin was recovered by flotation in a single stage. The operation was also examined during multiple cycles, i.e., following regeneration of resin; the high efficiency of both processes remained rather constant. Many thanks are due to the European Union – Energy, Environment and Sustainable Development (5th Framework programme) for funding the METASEP research project (for more information see reference 28) with contract no EVK1‐CT‐2000‐00083 and to the coordinator Dr. V. Mavrov (Inst. Envir. Compatible Process Tech., Univ. Saarland). Also, to Ms. S. Pataroudi, chemist, for experimental collaboration.