A carboxyl functionalized bis-triazole Schiff base as an effective inhibitor for Q235 steel in 1 M HCl

Background Q235 steel is susceptible to severe corrosion during the pickling process, especially in hydrochloric acid media, which not only shortens the service life of the equipment, but also may cause safety hazards and environmental pollution. Methods : A bis-triazole Schiff base carboxylic acid (BTSCA) was synthesized, named the 5-((4-(4H-1,2,4-triazol-4-yl) benzylidene) amino)-1H-1,2,4-triazole-3-carboxylic acid. The present study investigates the inhibitory performance of Q235 steel in a 1 M HCl solution containing BTSCA. The experimental methods adopted were weight loss method and electrochemical method. Significant findings : The results show that BTSCA has a good inhibitory efficiency on Q235 steel in 1 M HCl solution, which can reach 98.98%. Kinetic and thermodynamic analyses explained inhibitory mechanism of the compound, and the results showed that the adsorption behavior was in accordance with the Langmuir isotherm. The surface morphology of Q235 steel was characterized by scanning electron microscope (SEM) and atomic force microscope (AFM). Density functional theory (DFT) was used to analyze the inhibitory mechanism of BTSCA. Combined with molecular dynamics simulation (MD), the most stable configuration, adsorption sites and adsorption energy of BTSCA on the steel surface were determined.