Rates of extraction of zinc into organic single drops containing dithizone

Abstract

The rate of extraction of zinc from an aqueous phase, pH 4.0–5.2, by single drops of chloroform containing dithizone is reported. Rates for both drop travel and drop formation are given. The rates are compared with those of previous workers, but in this study the interfacial area is controlled and measured. Arguments are presented to demonstrate that the locale of the reaction is at the liquid–liquid interface and not in the hydrodynamic layer or bulk phase on the aqueous side of the interface as reported by previous workers.

Criteria are presented which can be used to test for the locale of the general reaction between any extractant and metal in liquid–liquid contacting.

The present rate data may be accounted for by Chapman's model of chemical reaction at the interface coupled with diffusional transfer of all the species taking part in the overall reaction.