Corrosion Inhibition of 2-Aminobenzimidazole and Its Derivatives for Carbon Steel in 0.5 mol/L H₂SO₄

Weight loss method and electrochemical technology were employed to evaluate the inhibition efficiency of 2-aminobenzimidazole (ABT) and 2-(n-hexylamino)-4-(3'-N,N-dimethylamino-propyl) amino-6-(benzimidazole-2-yl) amino-1,3,5-s-triazine (BACT) for carbon steel in 0.5 mol/L H₂SO₄ solution. The results showed that BACT had higher adsorption property than ABT in 0.5 mol/L H₂SO₄ solution. The inhibition efficiency could reach 86.07% with 0.20mmol/L BACT, while 42.13% with ABT of the same concentration. Surface activities of BACT and ABT in 0.5 mol/L H₂SO₄ solution were studied by surface tension meter. The adsorption ability for BACT and ABT on the surface of carbon steel was studied by quantum chemical calculations and molecular dynamics simulations. The results showed that the adsorption ability for BACT on Fe (100) surface in aqueous solution was much higher than that for ABT. Considering above results, the high inhibition efficiency of BACT should attributed to the enhancement of its adsorption property due to the surface activity of BACT and the addition of triazine group.