Asian Journal of Research in Chemistry

C. V. Deepaa ¹, V. G. Vasudha ², T. Sathiyapriya ¹

Affiliations
1 Department of Chemistry, Govt. Arts College, Coimbatore, Tamilnadu-641018, IN
2 Department of Chemistry, Nirmala College, Coimbatore, Tamilnadu-641018, IN

Abstract

The inhibition efficacy of the extract of Caesalpinia pulcherrima for the corrosion of mild steel in 1N hydrochloric acid was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) techniques. The results indicate that CP flowers serve as a good corrosion inhibitor of mixed type with efficiency as high as 95% at 0.6% inhibitor concentration.

Keywords

Caesalpinia pulcherrima, Mild Steel, Acid Medium, Corrosion Inhibitor.

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V. G. Vasudha ¹, R. Saratha ²

Affiliations
1 Department of Chemistry, Nirmala College for Women, Coimbatore-18, IN
2 Dept. of Chemistry, Avinashilingam University for Women, Coimbatore-43, Tamilnadu, IN

Abstract

The corrosion inhibition of mild steel in 1N HCl by acid extract of Nyctanthes arbortristis (night jasmine) leaves (NAL) has been studied using weight loss method. The results of the study reveal that NAL extract is a very good environment- friendly corrosion inhibitor for mild steel in acid medium with maximum inhibition efficiency of 90% at 2% v/v concentration. Inhibition efficiency of the extract is found to vary with concentration, temperature and period of immersion. Thermodynamic consideration reveals that adsorption of extract constituents on mild steel surface is spontaneous. Langmuir, Temkin, Freundlich and Flory-Huggins adsorption isotherms are obeyed. Physical adsorption mechanism is proposed for the adsorption of the inhibitor from the trend of variation of inhibition efficiency with temperature and the values of ΔG.

Keywords

Nyctanthes arbortristis Leaves, Corrosion Inhibitor, Mild Steel, HCL Medium.

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