The corrosion of mild steel in 0.5 M H2SO4 acid solution and the inhibition process by wheat starch (WS) was investigated using weight loss and potentiodynamic polarization measurement techniques respectively. Gravimetric results revealed that there is significant reduction in the corrosion rate of mild steel in the presence of inhibited solution compared to blank solution, and also the inhibition efficiency was found to depend on the concentration of the WS. Data on potentiodynamic polarization results confirmed that WS exhibited mixed type inhibition behaviour, though the cathodic effect was more pronounced. The mode of WS adsorption on the corroding metal surface followed Langmuir isotherm model. In addition, the trend of inhibition efficiency with temperature, activation energy and heat of adsorption parameters revealed a strong interaction between the WS constituents and the corroding metal surface, thus indicating that WS lowered the corrosion process by blanketing the mild steel surface through chemical adsorption mechanism. The mechanism of inhibition was discussed in the light of the chemical structure of starch.
International Journal of Engineering and Technologies (Volume 10)
S. C. Nwanonenyi et al., "Protection of Mild Steel Corrosion in Sulphuric Acid Environment Using Wheat Starch", International Journal of Engineering and Technologies, Vol. 10, pp. 11-21, 2017