The corrosion inhibition efficiencies of Schiff base 3-formylindole-4-aminobenzoic acid (3FI4ABA) on mild steel (MS) and copper in 1.0？M HCl solution have been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies. The results show that inhibition efficiencies on both metals increase with increasing the concentration of the inhibitor. 3FI4ABA exhibited comparatively good inhibition towards mild steel in HCl medium even at low concentrations. The adsorption of inhibitor on the surfaces of the corroding metal mild steel and copper obeys the Langmuir isotherm. Polarization studies revealed that 3FI4ABA acts as a mixed-type inhibitor. Thermodynamic parameters ( , ) were calculated using the Langmuir adsorption isotherm. 1. Introduction Schiff bases are organic molecules possessing azomethine linkage (C=N) and have innumerable advantages, right from pharmaceutical applications to the corrosion inhibitions, in the various fields of science. The heteroatoms present in these molecules are of key importance and are responsible for the corrosion inhibition in acidic media on the metal surface [1–3]. Some recently reported Schiff bases showed effective inhibition for mild steel (MS), aluminum, copper, and zinc in acidic media [4–11]. The study on MS and copper corrosion has become much important particularly in industrial and academic fields. Enormous use of hydrochloric acid for acid pickling, descaling, and cleaning process of mild steel surface are the major reasons for the corrosion problems in the world. Increasing efforts have been made to study the corrosion behavior of metals and mechanism of inhibition during the past decade mainly through electrochemical investigations [8, 9]. Limited work has been reported for the corrosion inhibition of compounds derived from 3-formylindole in acid media. The present investigation was undertaken to examine the corrosion inhibition capacity and mechanism of inhibition of a novel heterocyclic Schiff base (3FI4ABA) molecules derived from 3-formylindole and 4-aminobenzoic acid in 1？M？HCl solution on MS and Copper. The study was performed using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization analysis. 2. Experimental 2.1. Inhibitor Heterocyclic Schiff base was obtained by the condensation of equimolar mixture of 3-formylindole and 4-amino benzoic acid in ethanol. The reaction mixture was refluxed for 2 hours, evaporated and cooled in ice bath to obtain yellow coloured compound. Figure 1 shows
References
[1]
F. Bentiss, M. Traisnel, L. Gengembre, and M. Lagrenée, “Inhibition of acidic corrosion of mild steel by 3,5-diphenyl-4H-1,2,4-triazole,” Applied Surface Science, vol. 161, no. 1, pp. 194–202, 2000.
[2]
A. Raman and P. labine, Reviews on Corrosion Inhibitor Science and Technology, vol. 1, NACE, Houston, Tex, USA, 1986.
[3]
E. E. Oguzie, “Corrosion inhibition of mild steel in hydrochloric acid solution by methylene blue dye,” Materials Letters, vol. 59, no. 8-9, pp. 1076–1079, 2005.
[4]
A. Yurt and ？. Ayk？n, “Diphenolic Schiff bases as corrosion inhibitors for aluminium in 0.1？M HCl: potentiodynamic polarisation and EQCM investigations,” Corrosion Science, vol. 53, no. 11, pp. 3725–3732, 2011.
[5]
A. K. Singh, S. K. Shukla, M. Singh, and M. A. Quraishi, “Inhibitive effect of ceftazidime on corrosion of mild steel in hydrochloric acid solution,” Materials Chemistry and Physics, vol. 129, no. 1-2, pp. 68–76, 2011.
[6]
M. Behpour, S. M. Ghoreishi, N. Soltani, M. Salavati-Niasari, M. Hamadanian, and A. Gandomi, “Electrochemical and theoretical investigation on the corrosion inhibition of mild steel by thiosalicylaldehyde derivatives in hydrochloric acid solution,” Corrosion Science, vol. 50, no. 8, pp. 2172–2181, 2008.
[7]
K. S. Jacob and G. Parameswaran, “Corrosion inhibition of mild steel in hydrochloric acid solution by Schiff base furoin thiosemicarbazone,” Corrosion Science, vol. 52, no. 1, pp. 224–228, 2010.
[8]
S. Deng, X. Li, and H. Fu, “Alizarin violet 3B as a novel corrosion inhibitor for steel in HCl, H2SO4 solutions,” Corrosion Science, vol. 53, no. 11, pp. 3596–3602, 2011.
[9]
X. Li, S. Deng, and H. Fu, “Blue tetrazolium as a novel corrosion inhibitor for cold rolled steel in sulfuric acid solution,” Materials Chemistry and Physics, vol. 129, no. 3, pp. 696–700, 2011.
[10]
A. Bansiwal, P. Anthony, and S. P. Mathur, “Inhibitive effect of some Schiff bases on corrosion of aluminium in hydrochloric acid solutions,” British Corrosion Journal, vol. 35, no. 4, pp. 301–303, 2000.
[11]
S. Li, S. Chen, S. Lei, H. Ma, R. Yu, and D. Liu, “Investigation on some Schiff bases as HCl corrosion inhibitors for copper,” Corrosion Science, vol. 41, no. 7, pp. 1273–1287, 1999.
[12]
ASTM, “Standard recommended practice for the laboratory immersion corrosion testing of metals,” Tech. Rep. AST G-31-72, ASTM, Philadelphia, Pa, USA, 1990.
[13]
H. Ashassi-Sorkhabi, B. Shaabani, and D. Seifzadeh, “Effect of some pyrimidinic Shciff bases on the corrosion of mild steel in hydrochloric acid solution,” Electrochimica Acta, vol. 50, no. 16-17, pp. 3446–3452, 2005.
[14]
I. B. Obot and N. O. Obi-Egbedi, “Adsorption properties and inhibition of mild steel corrosion in sulphuric acid solution by ketoconazole: experimental and theoretical investigation,” Corrosion Science, vol. 52, no. 1, pp. 198–204, 2010.
[15]
M. A. Quraishi, D. Jamal, and M. Luqman, “Corrosion behaviour of VTS, STS and DTS inhibitors in formic and acetic acids,” Indian Journal of Chemical Technology, vol. 9, no. 6, pp. 479–483, 2002.
[16]
K. C. Emregül and O. Atakol, “Corrosion inhibition of iron in 1 M HCl solution with Schiff base compounds and derivatives,” Materials Chemistry and Physics, vol. 83, no. 2-3, pp. 373–379, 2004.
[17]
X. Li, S. Deng, H. Fu, and T. Li, “Adsorption and inhibition effect of 6-benzylaminopurine on cold rolled steel in 1.0 M HCl,” Electrochimica Acta, vol. 54, no. 16, pp. 4089–4098, 2009.
[18]
E. Cano, J. L. Polo, A. L. A. Iglesia, and J. M. Bastidas, “A study on the adsorption of benzotriazole on copper in hydrochloric acid using the inflection point of the isotherm,” Adsorption, vol. 10, no. 3, pp. 219–225, 2004.
[19]
F. Bentiss, M. Lebrini, and M. Lagrenée, “Thermodynamic characterization of metal dissolution and inhibitor adsorption processes in mild steel/2,5-bis(n-thienyl)-1,3,4-thiadiazoles/ hydrochloric acid system,” Corrosion Science, vol. 47, no. 12, pp. 2915–2931, 2005.
[20]
W. H. Li, Q. He, S. T. Zhang, C. L. Pei, and B. R. Hou, “Some new triazole derivatives as inhibitors for mild steel corrosion in acidic medium,” Journal of Applied Electrochemistry, vol. 38, no. 3, pp. 289–295, 2008.
[21]
H. H. Hassan, E. Abdelghani, and M. A. Amin, “Inhibition of mild steel corrosion in hydrochloric acid solution by triazole derivatives. Part I. Polarization and EIS studies,” Electrochimica Acta, vol. 52, no. 22, pp. 6359–6366, 2007.
[22]
M. S. Abdel-Aal and M. S. Morad, “Inhibiting effects of some quinolines and organic phosphonium compounds on corrosion of mild steel in 3M HCl solution and their adsorption characteristics,” British Corrosion Journal, vol. 36, no. 4, pp. 253–260, 2001.
[23]
P. Bommersbach, C. Alemany-Dumont, J. P. Millet, and B. Normand, “Formation and behaviour study of an environment-friendly corrosion inhibitor by electrochemical methods,” Electrochimica Acta, vol. 51, no. 6, pp. 1076–1084, 2005.
[24]
F. Mansfeld, “Recording and analysis of AC impedance data for corrosion studies,” Corrosion, vol. 36, no. 5, pp. 301–307, 1981.
[25]
I. L. Rosenfield, Corrosion Inhibitors, McGraw-Hill, New York, NY, USA, 1981.
[26]
A. S. Priya, V. S. Muralidharam, and A. Subramannia, “Development of novel acidizing inhibitors for carbon steel corrosion in 15% boiling hydrochloric acid,” Corrosion, vol. 64, no. 6, pp. 541–552, 2008.
[27]
M. El Azhar, B. Mernari, M. Traisnel, F. Bentiss, and M. Lagrenée, “Corrosion inhibition of mild steel by the new class of inhibitors [2,5-bis(n-pyridyl)-1,3,4-thiadiazoles] in acidic media,” Corrosion Science, vol. 43, no. 12, pp. 2229–2238, 2001.
[28]
A. Yurt, A. Balaban, S. U. Kandemir, G. Bereket, and B. Erk, “Investigation on some Schiff bases as HCl corrosion inhibitors for carbon steel,” Materials Chemistry and Physics, vol. 85, no. 2-3, pp. 420–426, 2004.
[29]
J. R. Macdonald, W. B. Johnson, and J. R. Macdonald, Theory in Impedance Spectroscopy, John Wiley & Sons, New York, NY, USA, 1987.
[30]
M. MaCafferty and N. Hackerman, “Double layer capacitance of iron and corrosion inhibition with polymethylene diamines,” Journal of the Electrochemical Society, vol. 119, no. 2, pp. 146–154, 1972.
[31]
X. Li, S. Deng, and H. Fu, “Synergism between red tetrazolium and uracil on the corrosion of cold rolled steel in H2SO4 solution,” Corrosion Science, vol. 51, no. 6, pp. 1344–1355, 2009.
[32]
E. S. Ferreira, C. Giacomelli, F. C. Giacomelli, and A. Spinelli, “Evaluation of the inhibitor effect of L-ascorbic acid on the corrosion of mild steel,” Materials Chemistry and Physics, vol. 83, no. 1, pp. 129–134, 2004.
[33]
Q. Qu, Z. Hao, S. Jiang, L. Li, and W. Bai, “Synergistic inhibition between dodecylamine and potassium iodide on the corrosion of cold rolled steel in 0.1？M phosphoric acid,” Materials and Corrosion, vol. 59, no. 11, pp. 883–888, 2008.
[34]
F. Bentiss, M. Traisnel, and M. Lagrenee, “The substituted 1,3,4-oxadiazoles: a new class of corrosion inhibitors of mild steel in acidic media,” Corrosion Science, vol. 42, no. 1, pp. 127–146, 2000.
[35]
D. P. Schweinsberg, G. A. George, A. K. Nanayakkara, and D. A. Steinert, “The protective action of epoxy resins and curing agents-inhibitive effects on the aqueous acid corrosion of iron and steel,” Corrosion Science, vol. 28, no. 1, pp. 33–42, 1988.
[36]
H. Shokry, M. Yuasa, I. Sekine, R. M. Issa, H. Y. El-Baradie, and G. K. Gomma, “Corrosion inhibition of mild steel by Schiff base compounds in various aqueous solutions: part 1,” Corrosion Science, vol. 40, no. 12, pp. 2173–2186, 1998.
[37]
A. K. Singh and M. A. Quraishi, “Inhibiting effects of 5-substituted isatin-based Mannich bases on the corrosion of mild steel in hydrochloric acid solution,” Journal of Applied Electrochemistry, vol. 40, no. 7, pp. 1293–1306, 2010.
[38]
S. M. Mili？ and M. M. Antonijevi？, “Some aspects of copper corrosion in presence of benzotriazole and chloride ions,” Corrosion Science, vol. 51, no. 1, pp. 28–34, 2009.
