Studies on Extraction Behaviour of Cobalt(II) with Nitrobenzoylprazolone-5

Abstract

The extraction of Cobalt(II) from aqueous solution using 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone (HPMNP) in various organic solvents was studied as a function of pH and extractant concentration. Extraction into organic chloro-form phase was more efficient than with any other solvent. The extraction equilibrium constant was found to be log K ex = −7.04. Optimum conditions for extraction of Co(II) exist at pH of between 5.5 and 7.0, ionic strength of 0.3 M and constant extractant concentration of 0.02 M. Shaking the organic Co(II) chelate complex with 0.2 M acid strips the Co(II) ions into the aqueous phase. It was established that Co(II) complex extracted is of composition, Co(PMNP) 2 .