Water Science & Technology Vol 65 No 10 pp 1765–1773 © IWA Publishing 2012 doi:10.2166/wst.2012.907

Application of ionic liquids for the removal of heavy metals from wastewater and activated sludge

Maria Fuerhacker, Tadele Measho Haile, Daniel Kogelnig, Anja Stojanovic and Bernhard Keppler

This paper presents the results of adsorption studies on the removal of heavy metals (Cr, Cu, Cd, Ni, Pb and Zn) from standard solutions, real wastewater samples and activated sewage sludge using a new technique of liquid–liquid extraction using quaternary ammonium and phosphonium ionic liquids (ILs). Batch sorption experiments were conducted using the ILs [PR4][TS], [PR4][MTBA], [A336][TS] and [A336][MTBA]. Removal of these heavy metals from standard solutions were not effective, however removal of heavy metals from the industrial effluents/wastewater treatment plants were satisfactory, indicating that the removal depends mainly on the composition of the wastewater and cannot be predicted with standard solutions. Removal of heavy metals from activated sludge proved to be more successful than conventional methods such as incineration, acid extraction, thermal treatment, etc. For the heavy metals Cu, Ni and Zn, ≥90% removal was achieved.

Keywords: activated sludge; heavy metal removal; ionic liquids; wastewater

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