Steel corrosion is a major and costly problem to industrialists and construction workers. The inhibiting effect of dioctyl phthalate on the corrosion of mild steel was carried out in 1.0 M solution of HCl as the corrosion medium using the weight loss method. The adsorption of the dioctyl phthalate on the surface of the mild steel in 1.0 M HCl was found to follow the physisorption mechanism and also follow the first order rate law. The corrosion rate was found to be di-rectly proportional to the temperature of the medium, and inversely proportional to the concentration of the inhibitor in solution. The activation energy increases with increase in the concentration of the inhibitor. Values of standard free energy change, are consistently below ﹣20 kJmol﹣1. This solidly established that the adsorption mechanism of the dioctyl phthalate on mild steel surface is physisorption. Langmuir and Freundlich adsorption isotherms were used, with Freundlich isotherm as best fit for the modelling of the adsorption process. The value nF in Freundlich isotherm which, indicates the intensity of adsorption, was found to be in the average of 0.717 not far from the typical value of 0.6 nF.
Cite this paper
Emmanuel, M. , Nwufo, B. T. and Ekwenchi, M. M. (2018). Inhibiting Effect of Dioctyl Phthalate on the Corrosion of Mild Steel in 1.0 M Hydrochloric Acid Solution. Open Access Library Journal, 5, e4927. doi: http://dx.doi.org/10.4236/oalib.1104927.
Opila, E.J. and Jacobson, N.S. (1999) Corrosion of Ceramic Materials. NASA Lewis Research Center. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/ 20000004900.pdf
Barbra, S.A. and Robert, K.G. (2006) What Is Corrosion? The Electrochemical Society Interface, 1-3. https://www.electrochem.org/dl/interface/spr/spr06/ spr06_p24-26.pdf
Fin?garand, M. and Milo?ev, I. (2010) Inhibition of Copper Corrosion by 1,2,3-benzotriazole: A Review. Corrosion Science, 52, 2737-2749. https://doi.org/10.1016/j.corsci.2010.05.002
El-Sherif, R.M. and Badawy, W.A. (2011) Mechanism of Corrosion and Corrosion Inhibition of Tin in Aqueous Solutions Containing Tartaric Acid. International Journal of Electrochemical Science, 6, 6469-6482. http://electrochemsci.org/papers/vol6/6126469.pdf
Onen, A.I., Nwufo, B.T., Ebenso, E.E. and Hlophe, R.M. (2010) Titanium (IV) Oxide as Corrosion Inhibitor for Aluminium and Mild Steel in Acidic Medium. International Journal of Elec-trochemical Science, 5, 1563-1573. http://electrochemsci.org/papers/vol5/5111563.pdf
Amin, M.A., Abd El-Rehim, S.S., El-Sherbini, E.E.F. and Bayoumi, R.S. (2008) Chemical and Electrochemical (AC and DC) Studies on the Corrosion Inhibition of Low Carbon Steel in 1.0 M HCl Solution by Succinic Acid—Temperature Effect, Activation Energies and Thermodynamics of Adsorption. International Journal of Electrochemical Science, 3, 199-215. http://www.electrochemsci.org/papers/vol3/3020199.pdf
Patel, N.S., Jauhariand, S., Mehta, G.N., Al-Deyab, S.S., Warad, I. and Hammouti, B. (2013) Mild Steel Corrosion Inhibition by Various Plant Extracts in 0.5 M Sulphuric Acid. International Journal of Electrochemical Science, 8, 2635-2655. http://electrochemsci.org/papers/vol8/80202635.pdf
Zarrouk, A., Hammouti, B., Zarrok, H., Al-Deyab, S.S. and Messali, M. (2011) Temperature Effect, Activation Energies and Thermodynamic Adsorption Studies of L-Cysteine Methyl Ester Hydrochloride as Copper Corrosion Inhibitor in Nitric Acid 2M. International Journal of Electrochemical Science, 6, 6261-6274. http://repository.taibahu.edu.sa/bitstream/handle/123456789/ 6111/Temperature%20Effect,%20Activation%20Ener-gies%20 and%20Thermodynamic%20Adsorption%20Studies%20of%20 L-Cysteine%20Methyl%20Ester%20Hydrochloride%20As%20 Copper%20Corrosion%20Inhibitor%20In%20Nitric%20Acid%202 M.pdf?sequence=1
Shukla, S.K. and Ebenso, E.E. (2011) Corrosion Inhibition, Adsorption Behavior and Thermodynamic Properties of Streptomycin on Mild Steel in Hydrochloric Acid Medium. International Journal of Electrochemical Science, 6, 3277-3291. http://electrochemsci.org/papers/vol6/6083277.pdf
Zarrouk, A., Zarrok, H., Salghi, R., Bouroumane, Hammouti, B., Al-Deyab, S.S. and Touzani, R. (2012) The Adsorption and Corrosion Inhibition of 2-[Bis-(3,5-dimethyl-pyrazol-1-ylmethyl)-amino]-pentanedioic Acid on Carbon Steel Corrosion in 1.0 m HCl. International Journal of Electrochemical Science, 7, 10215-10232. http://electrochemsci.org/papers/vol7/71010215.pdf
Nair, R.N., Sharma, S., Sharma, I.K., Verma, P.S. and Sharma, A. (2010) Inhibitory Efficacy of Piper Nigrum Linn. Extract on Corrosion of AA1100 in HCL. Rasayan Journal of Chemistry, 3, 783-795. http://rasayanjournal.co.in/vol-3/issue-4/30.pdf
Nnanna, L.A., Anozie, I.U., Avoaja, A.G.I., Akoma, C.S. and Eti, E.P. (2011) Comparative Study of Corrosion Inhibition of Aluminium Alloy of Type AA3003 in Acidic and Alkaline Media by Euphorbia hirta Extract. African Journal of Pure and Applied Chemistry, 5, 265-271. http://www.academicjournals.org/journal/AJPAC/article-full- text-pdf/021613A1309
Behpour, M., Ghoreishi, S.M., Soltani, N., Salavati-Niasari, M., Hamadanian, M. and Gandomi, A. (2008) Electrochemical and Theoretical Investigation on the Corrosion Inhibition of Mild Steel by Thiosalicylaldehyde Derivatives in Hydrochloric Acid Solution. Corrosion Science, 50, 2172-2181. https://doi.org/10.1016/j.corsci.2008.06.020
Onen A.I, Barminas, J.T, and Jacob, J. (2013) Inhibitory Action of Ficus carica Extracts on Aluminium Corrosion in Acidic Medium. Chemical Science Transaction, 2, 1326-1333.
Pavithra, M.K., Venkatesha, T.V. and Punith Kumar, M.K. (2013) Inhibiting Effects of Rabeprazole Sulfide on the Corrosion of Mild Steel in Acidic Chloride Solution. International Journal of Electrochemistry, 1-9.
Adejo, S.O., Gbertyo, J.A. and Ahile, J.U. (2013) Inhibitive Properties and Adsorption Consideration of Ethanol Extract of Manihotesculentum Leaves for Corrosion Inhibition of Aluminium in 2 M H2SO4. International Journal of Modern Chemistry, 4, 137-146.
Khadom, A.A., Yaro, A.S. and Abdul, A.H. (2010) Adsorption Mechanism of Benotriazole for Corrosion Inhibition of Coppper-Nickel Alloy in Hydrochloric Acid. Journal of Chilean Chemical Society, 55, 150-152. https://doi.org/10.4067/S0717-97072010000100035
Popova, A., Sokolova, E., Raicheva, S. and Christov, M. (2003) AC and DC Study of the Temperature Effect on Mild Steel Corrosion in Acid Media in the Presence of Benzimidazole Derivatives. Corrosion Science, 45, 33-58.
Adejo, S.O. and Ekwenchi, M.M. (2014) Proposing a New Empirical Adsorption Isotherm Known as Adejo-Ekwenchi Isotherm. IOSR Journal of Applied Chemistry, 6, 66-71. https://www.researchgate.net/profile/Sylvester_Adejo/publication/ 269276792_PROPOSING_A_NEW_EMPIRICAL_ADSORPTION _ISOTHERM_KNOWN_AS_ADEJO-EKWENCHI_ISOTHERM/ links/54bcf5be0cf24e50e940bac7.pdf
Nwigbo, S.C., Okaforand, V.N. and Okewale, A.O. (2012) Comparative Study of ElaeisGuiniensis Exudates (Palm Wine) as a Corrosion Inhibitor for Mild Steel in Acidic and Basic Solutions. Research Journal of Applied Sciences, Engineering and Technology, 4, 1035-1039. http://www.airitilibrary.com/Publication/alDetailedMesh?docid =20407467-201205-201510220010-201510220010-1035-1039