Assessment of Langmuir and Freundlich Isotherms Fit for Mildsteel Pipe Corrosion inhibition Study by Extracts of Castor and Rubber Seeds: A Comparative Analysis
1Offurum, J.C.; 2Nwakaudu, M.S.; 2Ndukwe O.C. 2Kamalu C.I.O. & 2Onyelucheya O.E.
1Department of Chemical Engineering, Imo State Polytechnic, Umuagwo-Ohaji
2Department of Chemical Engineering, Federal University of Technology, Owerri
E-mail: jullyengine@yahoo.com
ABSTRACT
The present study is concerned with the Comparative Assessment of Langmuir and Freundlich Isotherms Fit for Mildsteel Pipe Corrosion Inhibition Study by Extracts of Castor and Rubber Seeds. A flow system (locally designed, but with standard equipment) was used for the corrosion inhibition assessment at 60oC (temperature), 60% stroke (dosage) and 20g/L (inhibitor concentration in acid medium). The highest corrosion rate was recorded at 32hours, while the least was recorded at 4hours, which shows that loss of integrity of the material (via corrosion) increases with time. The empirical constant of the Langmuir model, b was found to have all-negative values, affirming a continuous heat energy demand for the corrosion process with time; the model, in this regard, made a good fit for the data (for both samples). On the contrary, the Freundlich model does not fit the data, as the Freundlich intensity factor, Kf (for both samples) have extremely wide values. The Langmuir model is, thus, preferred to the Freundlich model for data fit in corrosion inhibition assessment study.
Keywords: Comparative Assessment, Langmuir Isotherm, Freundlich Isotherm, Corrosion Inhibition, Castor Seed Oil, Rubber Seed Oil.
