Voltammetry of Dissolved Iron(III)–Nitrilotriacetate–Hydroxide System in Water Solution

Abstract

The investigation of the dissolved iron(III) -nitrilotriacetate -hydroxide system in the water solution (I ¼ 0.1 mol L À1 in NaClO 4 ; pH 8.0 AE 0.1) using differential pulse cathodic voltammetry, cyclic voltammetry, and sampled direct current (DC) polarography, was carried out on a static mercury drop electrode (SMDE , and À 0.154 AE 0.010 V, respectively. Although known previously in the literature, these four species have now for the first time been recorded simultaneously, i.e. proved to exist simultaneously under the given conditions.

Comparison of Nitrilotriacetic Acid and [S,S]-Ethylenediamine-N,N′-disuccinic Acid in UV–Fenton for the Treatment of Oil Sands Process-Affected Water at Natural pH

“…The stability constants of metal–chelates increases with increasing charge and decreasing radius of the metal ions, and with the number of coordinating groups in the ligands . Generally, the stability constants of metal–NTA complexes are smaller than those of metal–EDDS complexes, such as 15.9 ,, for Fe­(III)­NTA and 20.6 for Fe­(III)­EDDS, 18.45 ,, for Cu­(II)­NTA and 14.2 or 13.1 for Cu­(II)­EDDS, and 7.4 for Mn­(II)­NTA and 8.95 ,, for Mn­(II)­EDDS (ignoring the temperature (20 or 25 °C) difference for these values), indicating a higher strength of the interaction of metal ions in OSPW with EDDS than that with NTA. EDDS with six coordinating sites (two N donors and four O donors) forms both five- and six-membered chelate rings with metal ions with a ratio of 1:1, while NTA as a tetradentate ligand with four coordinating sites (one N donor and three O donors) can form 1:1 and 2:1 complexes with metal ions .…”

Iron(III)‐Complexes Engaged in the Biochemical Processes in Seawater. II. Voltammetry of Fe(III)‐Malate Complexes in Model Aqueous Solution

“…In that concentration range, polynuclear (dimers and trimers) complexes of Fe(III) were detected as well. However, in this study was used C Fe < 1 Â 10 À4 mol L À1 and much higher C mal , as already mentioned, polynuclear species were not formed [29]. Titration of malate solutions (C mal ¼ 2.5 Â 10 À2 mol L À1 and 0.1 mol L…”

Iron metabolism in aerobes: Managing ferric iron hydrolysis and ferrous iron autoxidation

“…Hydrolysis of bound waters increases the stability of the ferric form and thus drives down the reduction potential. An example of this is the iron-NTA system in which, depending on the number of NTA and water molecules (and their hydrolysis) in the coordination sphere log β III varies from 24 to 52 with a corresponding decrease in reduction potential from −90 to −550 mV [13]. The experiments in Fig.…”