Synergistic corrosion inhibition of A₃steel in hydrochloric acid by Sodium dodecyl sulfate and 2‐mercaptopyridine: Experimental and theoretical calculations

Abstract

The inhibition performance of sodium dodecyl sulfate (SDS) and 2mercaptopyridine (2MP) corrosion inhibitors on A 3 steel in 0.5 M HCl increase with increasing of the inhibitor concentration (50-200 mg L −1 ). SDS and 2MP inhibitor follow Freundlich adsorption isotherm and Langmuir adsorption isotherm, respectively. These two inhibitors exhibit good synergistic inhibition effect on the corrosion of A 3 steel in 0.5 M HCl solution when the mass ratio of SDS:2MP is 1:4. Gibbs free energy of the mixture is lower and the mixture exhibit good adsorption stability. 2MP molecule are adsorbed on metal surface through N atom and sulfhydryl group. SDS molecule interacts with metal through O atoms while the alkyl chain pointing to the test solution. This adsorption configuration is beneficial to the formation of the inhibitor film, the migration of the corrosive particles to the metal surface was hindered and thus the metal surface was protected.

The inhibition performance of anionic surfactant and zwitterionic surfactant toward the corrosion of carbon steel in NaCl solution

“…9 The raw materials of corrosion inhibitor are relatively easy to obtain, and the corrosion process of metal can be effectively slowed down when a small amount of inhibitor is added, so it is widely praised by people in the process of industrial production. [10][11][12][13] Nowadays, the study on efficient organic corrosion inhibitors has become an important direction. [14][15][16][17][18] The existence of heteroatoms, 19 functional groups 20,21 will affect the charge transfer and bonding process between inhibitor molecules and the metal.…”

“…Seawater is rich in many elements such as Na + , K + , Ca 2+ , Cl − , and SO 4 2− , among them, Cl − is one of the important ions induce metal corrosion 9 . The raw materials of corrosion inhibitor are relatively easy to obtain, and the corrosion process of metal can be effectively slowed down when a small amount of inhibitor is added, so it is widely praised by people in the process of industrial production 10–13 . Nowadays, the study on efficient organic corrosion inhibitors has become an important direction 14–18 …”