抄録
A continuous-flow system for the separation of lead(II) (PbII) from zinc(II) (ZnII) was developed. The system consists of two extraction coils—one for forward-extraction and the other for back-extraction—connected in series through a phase separator. Firstly, in the forward-extraction process, most PbII and a small amount of ZnII are extracted into chloroform phase with dithizone (H2dz). Subsequently, in the back-extraction process, PbII is back-extracted into the aqueous phase with nitric acid while the ZnII is retained in the organic phase. The experimental conditions were optimized based on the kinetic constants of ZnII and PbII in forward- and back-extraction. The optimal flow system can quantitatively separate PbII from ZnII by a single injection of a sample solution. This method is also applicable to a sample solution containing a much higher concentration of ZnII (4.89 × 10-3 mol dm-3) than that of PbII (5.14 × 10-6 mol dm-3).
