Mg(II) and Zn(II) сomplexonates with a 1,3-diamino-2-propanol phosphorus-containing derivative as corrosion and scaling inhibitors

Abstract

Based on IOMS-1, an available, rather inexpensive and rather popular domestic scaling inhibitor used for stabilization treatment of water utilisation systems at industrial plants, small and large power plants and in utility systems, a new formulation has been developed that meets the requirements for phosphonate-based formulations of this type. In order to increase the scaling inhibition activity and ensure the ability to inhibit the corrosion of metals, rather small amounts of diaminopropanolmethylphosphonic acids (DPP) and their Zn(II) and Mg(II) complexes that showed high inhibitive capability were added to the formulation. Estimation of the effect of the DPP:metal molar ratio on the corrosion rate at various temperatures has shown that the maximum efficiency of corrosion inhibition is achieved at a DPP:Me molar ratio of 3:1–2:1 and with the DPP–Mg complexonate. In such case, the corrosion rate decreases with an increase in temperature, whereas it increases by about 8–10% per each 10℃ in the absence of complexonates. Since the use of DPP alone is economically unjustified, the efficiency of formulations obtained at various IOMS-1:DPP– Mg molar rations was studied. A high inhibitive activity both for scaling and corrosion was found at the molar ratio of the reagents of 3:1, respectively. The maximum scaling inhibition similar to that of DPP was achieved without lowering the cost efficiency of the new formulation compared to IOMS-1. © 2020, Russian Association of Corrosion Engineers. All rights reserved.