Author/Authors :
Agboola, Oluranti Department of Chemical Engineering - Covenant University, Ota, Nigeria , Adedoyin, Toluwani Department of Chemical Engineering - Covenant University, Ota, Nigeria , Sanni, Samuel E Department of Chemical Engineering - Covenant University, Ota, Nigeria , Fayomi, Sunday O Department of Chemical Engineering - Covenant University, Ota, Nigeria , Adedayo Omonidgbehin, Emmanuel Department of Biological Science - Covenant University, Ota, Nigeria , Esther Adegboye, Bose Department of Biochemistry - Covenant University, Ota, Nigeria , Ayoola, Ayodeji Department of Chemical Engineering - Covenant University, Ota, Nigeria , Omodara, Oladele Department of Chemical Engineering - Covenant University, Ota, Nigeria , Omoniyin Ayeni, Augustine Department of Chemical Engineering - Covenant University, Ota, Nigeria , Popoola, Patricia Department of Chemical - Metallurgical and Materials Engineering - Tshwane University of Technology, Pretoria, South Africa , Sadiku, Rotimi Department of Chemical - Metallurgical and Materials Engineering - Tshwane University of Technology, Pretoria, South Africa , Adeniyi Alaba, Peter Department of Chemical Engineering - University of Malaya, Malaysia
Abstract :
Corrosion inhibition of mild steel in an acidic environment using several concentrations of DNA from Manihot esculenta leaf (Cassava leaf) (MANIHOT ESCULENTA LEAFDNA) at different temperatures was examined using gravimetric analysis and linear polarization techniques. Three different isotherms (Langmuir, Freundlich and Flory-Huggins) were evaluated for their fitness to the experimental data. Based on the results, thermodynamic parameters regarding the DNA behaviour were calculated using the Freundlich adsorption isotherm because it gave the best description of the DNA inhibitor. The Freundlich adsorption isotherm shows that the adsorption of the DNA inhibitor to the surface of mild steel is by physisorption and the data obtained from the thermodynamic assessment illustrates a spontaneous and exothermic corrosion process. The morphologies of the mild steel surfaces with and without inhibitor were assessed by scanning electron microscopy (SEM). The SEM results showed that the presence of the DNA inhibitor slowed down the corrosion process. The micrograph for MANIHOT ESCULENTA LEAFDNA inhibitor showed a near smoother surface at 10 °C and 20 mg/L and 25 °C and 20 mg/L thus confirming their provision of more active surfaces. However, it was observed that the DNA inhibitor efficiency increased with increased DNA concentration, with the best inhibitor efficiency (74.2%) obtained at 10 °C for 20 mg/L DNA concentration. A mechanism of adsorption was also proposed which was validated by the data obtained from XRD analysis.
Keywords :
linear polarization , gravimetric analysis , DNA inhibitor , MANIHOT ESCULENTA LEAFDNA , Mild steel
