In-depth unveiling the interfacial adsorption mechanism of triazine derivatives as corrosion inhibitors for carbon steel in carbon dioxide saturated oilfield produced water

Abstract

In this work, two triazine derivatives (BTT-1 and BTT-2) were synthesized by the simple one-step condensation of three components and used as high-efficient corrosion inhibitors to deal with the corrosion issue of carbon steel (CS) in petroleum industry. Electrochemical tests indicate that both BTT-1 and BTT-2 present superior inhibition performance with the inhibition efficiency of 97.9 % and 98.4 % at a low concentration of 0.18 mM, respectively. Quantum chemical calculations reveal that compared to BTT-1 molecule with a butyl chain, the introduction of benzyl group endows BTT-2 molecule with more adsorption sites, which favors the adsorption of BTT-2 molecule on CS surface. Furthermore, the GFN-xTB calculations demonstrate that BTT-1 and BTT-2 could adsorb on CS surface through the formation of Fe−N and Fe−S bonds. Compared to BTT-1, BTT-2 exhibits stronger adsorption on CS surface by forming more and shorter bonds with a more negative adsorption energy, which accounts for the better inhibitive performance of BTT-2.