Thermodynamic Characteristics of Camel’s Urine as an Inhibitor for Mild Steel in 1.5 M H2SO4 Acid Solution
Ehteram A. Noor, Azza A. Al-Ghamdi and Aisha H. Al-Moubaraki
DOI : 10.3844/ajassp.2011.1353.1362
American Journal of Applied Sciences
Volume 8, Issue 12
Problem statement: The corrosion inhibition of mild steel in 1.5 M H2SO4 by Camel’s Urine (CU) addition was evaluated at five different temperatures in the range from 30-70°C by weight loss measurements. CU acts as a good inhibitor for the corrosion of mild steel in 1.5 M H2SO4. The value of inhibition efficiency increases with increasing both inhibitor concentration and solution temperature. Approach: The adsorption of CU constituents on the mild steel surface obeys the Langmuir adsorption isotherm suggesting a monolayer adsorption of CU species. Thermodynamic parameters for CU adsorption and mild steel corrosion were evaluated. The negative values of (ΔGoads) emphasize the spontaneity of the adsorption process and stability of the adsorbed layer. Results: The estimated high, positive value of ΔHoads ensures that CU species is adsorbed chemically on mild steel surface. All values of E*app for mild steel corrosion in inhibited solutions were lower than that for the uninhibited solution indicating the occurrence of chemisorption mechanism. Conclusion: The surface morphology of mild steel in absence and presence of inhibitor revealed that with increasing both CU concentration and solution temperature, mild steel surface is modified and looks smooth. Good correlation between the inhibitor constituents and its inhibitory action was obtained.
© 2011 Ehteram A. Noor, Azza A. Al-Ghamdi and Aisha H. Al-Moubaraki. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.