Adsorption of cationic Gemini surfactants on carbon steel surface and their anticorrosion performance in hydrochloric acid solution

Metal corrosion has hindered the advancement of new technologies. The surfactant as one kind of corrosion inhibitor can effectively restrain metal corrosion in corrosive medium. In this research, two cationic Gemini surfactants, 3,3′-(ethane-1,2-diyl)bis(1-octyl-1 H -imidazol-3-ium) dibromide ([C 8 im-2-C 8 im]Br 2 ) and 3,3′-(butane-1,4-diyl)bis(1-octyl-1 H -imidazol-3-ium) dibromide ([C 8 im-4-C 8 im]Br 2 ), have been prepared for the corrosion inhibition of carbon steels in 1.0 mol/L HCl solution. The weight loss measurement demonstrates that two inhibitors both achieve high inhibition efficiencyies at concentration of 0.50 mM for carbon steels in 1.0 mol/L HCl solution. By comparison, the anticorrosion performance of [C 8 im-2-C 8 im]Br 2 for carbon steel specimens in 1.0 mol/L HCl solution are better than that of [C 8 im-4-C 8 im]Br 2 , and the maximum corrosion efficiency can reach 96.15% at the temperature of 30°C. The determination of adsorption thermodynamics and kinetics parameters reveals that the adsorption behavior of two inhibitors on the steel surface is chemisorption and follows Langmuir isotherm. Good anticorrosion performance of the inhibitor for carbon steel in HCl solution owes to a dense and compact protective film formed onto the steel surface. It indicates that the proposed cationic Gemini surfactants have great prospect in the corrosion inhibition of metals. Graphical 3,3′-(ethane-1,2-diyl)bis(1-octyl-1 H -imidazol-3-ium) dibromide as a corrosion inhibitor demonstrates good anticorrosion performance for carbon steel in hydrochloric acid solution. The chemical adsorption of the inhibitor onto carbon steel surface enables to form a dense and compact protective layer.