Extraction of lead from water into nitrobenzene by using strontium dicarbollylcobaltate in the presence of benzo-15-crown-5

From extraction experiments and gamma-activity measurements, the extraction constant corresponding to the equilibrium Pb2+(aq)+SrL22+(nb)double left right arrow PbL22+ (nb)+Sr2+(aq) taking place in the two-phase water-nitrobenzene system (L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K-ex(Pb2+, SrL22+) = 0.1 +/- 0.1. Further, the stability constant of the benzo-15-crown-5-lead complex in nitrobenzene saturated with water was calculated for a temperature of 25 degrees C: log beta(nb)(PbL22+) = 13.2 +/- 0.1.