Hexadecyl trimethyl ammonium bromide-modified 4-mercaptopyridinde mixture for enhancement of corrosion resistance: Experimental and molecular dynamics simulation study

The synergistic effect between 4-mercaptopyridine (4MP) and hexadecyl trimethyl ammonium bromide (C(16)TAB) was studied using electrochemical method combined with weight loss measurements. The spontaneous adsorption of the inhibitor follows Langmuir isotherm. They work as mix-type inhibitor with predominant control of the cathodic process. The inhibition efficiency of the inhibitor mixture (C(16)TAB-MP) is higher than those of the individual component and increases with increasing of the inhibitor concentration. 4MP molecule adsorb on metal chemically through N and S atom, whereas C(16)TAB molecule through physisorption of N atom, after they coadsorbed on the iron surface, both of them adsorb through chemisorption. The distance between N-Fe and S-Fe in C(16)TAB-MP is shorter than that in the 4MP or C(16)TAB containing system. C(16)TAB and 4MP show good synergistic effect.