Potentiometric and spectrophotometric study of the solution equilibria in the nickel(II)–diethanolamine–water system in aqueous sodium perchlorate solutions at 25 °C

Abstract

The acid–base and complexation equilibria of the system nickel(II)-diethanolamine–water have been studied using and automated potentiometric–spectrophotometric titration system at 25 °C and at four ionic strengths (0.5, 1.0, 2.0 and 3.0 mol dm–3) in NaClO4 medium. The stoichiometric stability constants, obtained at the different ionic strengths, were correlated by means of the modified Bromley methodology and the corresponding thermodynamic constants were: log 0β011= 8.88 ± 0.02, log 0β110= 2.67 ± 0.02 and log 0β120= 4.42 ± 0.05.