THERMODYNAMICS STUDY FOR THE ASSESSMENT OF CORROSION INHIBITION OF MILDSTEEL PIPE BY CASTOR AND RUBBER SEED OILS

¹Offurum, J.C.; ²Nwakaudu, M.S.; ²Ndukwe O.C.; ¹Iheme C., ¹Mbadike C.A.

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 thermodynamics for the assessment of corrosion inhibition of mildsteel pipe by Castor and Rubber Seed Oils was studied in this research work. This was prompted due to the fact that temperature factor plays very important role in the corrosion a given material with time. Corrosion Inhibition assessment of the steel pipe, by the castor and rubber seed oil samples was performed at different times (of 4, 8, 16, 24 and 32hours) and temperatures (of 40, 50 and 60^oC) to know how much mass of the material will be degraded in a given time. Arrhenius concept was employed to study the temperature-dependence of the process, in which the results shows that corrosion rate increases with time, with the highest rate (42.67% for Castor Seed Oil, CSO and 30.66% for Rubber Seed Oil, RSO) observed at the highest time of 32hours. Also, enthalpy and entropy changes increases in the direction of increasing temperature and time, indicating an increasing demand for heat energy content. The deepening in the negativity of the free energy value is a response to the increased randomness in the adsorbed molecular layer, which made the reaction entropy-driven and spontaneous. However, the thermodynamic parameters studied were more established in cases involving Sample A (CSO) than in Sample B (RSO).

Keywords: Thermodynamics, Corrosion Inhibition, Mildsteel Pipe, Castor Seed Oil, Rubber Seed Oil.