N. Woller et al., REACTIVE LIQUID-LIQUID-EXTRACTION OF HEAVY-METALS FROM LEACHATE WITH OIL-SOLUBLE COMPLEXING SURFACTANTS, Colloids and surfaces. A, Physicochemical and engineering aspects, 117(1-2), 1996, pp. 189-200
Reactive liquid-liquid extraction is a well-known technology for the s
elective winning of metals. However, the application of this method in
environmental processing, such as the non-selective separation of hea
vy metals from waste water (e.g. leachate from landfills), is new. It
is shown that technical oil-soluble surfactants with complexing proper
ties are able to lower,the content of simultaneously present heavy met
als by about two or three orders of magnitude, starting at 10-100 mg l
(-1). By applying commercially available quinolines (such as LIX26(R))
and oximes (such as LIX84(R)), it is possible to extract the heavy me
tals Cu, Cr, Cd, Ni, Zn and Pb in one step, keeping within the limits
set by the German authorities. Bulk metals such as Ca remain in the wa
ste water. Besides fundamental investigations on the stoichiometry of
the extracting reaction, the extraction selectivity and the phase sepa
ration, experiments concerning the extraction and re-extraction speed
using a continuously operating mixer-settler were performed.