FUW TRENDS IN SCIENCE & TECHNOLOGY JOURNAL
(A Peer Review Journal)
e–ISSN: 2408–5162; p–ISSN: 2048–5170
keywords: Cleome gynandra; Solanumscabrum; inhibitory effect; potentiodynamic polarization; physisorption
The inhibition of corrosion of mild steel in hydrochloric acid solution by Solanumscabrum and Cloeme gynandra leaf extracts has been investigated via weight loss measurements and potentiodynamic polarization studies at 308, 318 and 328K. The inhibition efficiencies (%) increased with concentration of inhibitors and decrease with increasing temperature while activation energy of corrosion increases with increasing concentration. The average value of Ea (6.57 kJmol-1and 4.18 kJmol-1) for the two extracts, respectively were lower than 40.0 kJmol-1; implying that the inhibitors are physically adsorbed on the mild steel surface. The mean values of Qads were found to be -12.22 and -4.57 kJmol-1 for the inhibitors, respectively indicating that the adsorption process is exergonic. Inhibition of mild steel corrosion by Solanumscabrum and Cloeme gynandra follows first order kinetics. Physical adsorption mechanism is proposed for the inhibitors.
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