Indian Journal of Advances in Chemical Science Volume: 5, Issue 4: , September 2017

ISSN No.: 2320-0898 (Print); 2320-0928 (Electronic)

DOI:  10.22607/IJACS.2017.504010

Research Article

The corrosion inhibition of mild steel (MS) in 0.5 M H2SO4 solution by the methanolic extracts of Adansonia digitata (baobab) fruit pulp extract (ADPE) and A. digitata (baobab) fruit seeds extract (ADSE) was studied by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopic, and scanning electron microscopy (SEM) methods. The weight loss and polarization studies reveal that the corrosion inhibition efficiency increases with increase in the concentrations of inhibitors ADSE and ADPE. ADSE exhibited high corrosion inhibitor efficiency (74.5%) for MS. Tafel plots show that baobab fruit extracts act as efficient mixed-type corrosion inhibitors. The double-layer capacitance (Cdl) and charge transfer resistance (Rct) values derived from Nyquist plots proved the anticorrosive nature of extracts. The inhibition of corrosion is possibly due to adsorption of the extracts on MS surface. The adsorption obeys Langmuir adsorption isotherm. The low free energy of adsorption (ΔGads) values for both the extracts confirmed physisorption on MS surface. The SEM images confirmed severe surface deterioration of MS exposed to H2SO4 solution in the absence of inhibitors. The ADSE exhibited high efficiency as green and eco-friendly corrosion inhibitor for MS in acidic medium.

Key words:  Mild steel, Green inhibitor, Adansonia digitata, Acid corrosion.

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