A novel corrosion inhibitor of bis-benzimidazole derivative for mild steel: Synthesis, properties and mechanism investigation

Abstract

The application of corrosion inhibitor is still one of the effective ways to protect metals under high temperature and high pressure environment. In this paper, we have introduced a synthetic method for a novel bis-benzimidazole derivative, i.e., N, N-bis (-2-heptadecyl-benzimidazole) -1-hexylammonium chloride (HBH), and its solubility was improved by adding a specific surfactant (AEO-5) to form a highly efficient corrosion inhibitor system (HBH-A), and its corrosion inhibition was studied by weight loss, electrochemical measurements, SEM, EDS and XRD. The results showed that HBH-A inhibited the corrosion of N80 carbon steel in the corrosive medium. As the concentration of HBH-A increases, the corrosion inhibition rate exhibits a pattern of rapid initial growth followed by a slower increase. Electrochemical measurements demonstrate that HBH-A behaved as an effective mixed-type corrosion inhibitor, exhibiting a significant enhancement in the corrosion inhibition rate (η) with increasing concentrations of HBH-A. At a HBH-A concentration of 100 mg⋅L-1, the inhibition rate can outstrip 98%. Corrosion surface analysis further confirm that the HBH molecules are indeed adsorbed to form an adsorption film, and the surface exposure of N80 carbon steel was significantly decreased with the action of HBH-A, thus reducing the corrosion rate of N80 carbon steel.