The kinetics and mechanism of solvent extraction of Pr(iii) from chloride medium in the presence of two complexing agents with di-(2-ethylhexyl) phosphoric acid

Abstract

The extraction kinetics of Pr(III) from chloride medium containing two complexing agents lactic acid (HLac) and citric acid (H₃cit) with di-(2-ethylhexyl)phosphoric acid (D2EHPA, H₂A₂) have been investigated by constant interfacial area cell with lamina flow. The influence of stirring speed, temperature, specific interfacial area, extractant and hydrogen ion concentrations on the extraction rate has been studied. It is concluded that the extraction of Pr(III) takes place at the liquid–liquid interface, while the extraction regime belongs to diffusion-controlled kinetics process. The extraction rate equation and the rate-determining step have been obtained under the experimental conditions, and the extraction rate constant is calculated. The interfacial reaction model is proposed based on the kinetic steps.