Stability constants of manganese(II) alkylenediaminetetraacetates

Abstract

Ethylenediaminetetraacetic acids are abundant chelating agents in the aquatic environment due to their numerous industrial applications. One of the main environmental effects of these substances is the mobilization of metals, and for this reason it is important to evaluate the corresponding affinity constants. In this work, affinity constants of Mn (II) and two common chelating agents (EDTA and HPDTA) were measured by affinity potentiometry, in media with different ionic strengths. It was found that HPDTA forms stable complexes with Mn²⁺ in a wide range of pH values, and that the stability of these complexes is lower than that of the Mn-EDTA complexes.