Synthesis and evaluation of green corrosion inhibitor from rice husk to mitigate corrosion of carbon steel in NaCl environment

A systematic experimental investigation has been carried out to select, synthesize and study the effect of a green corrosion inhibitor on carbon steel in 0.6 M NaCl aqueous environment. Silica nanomaterials (nanosilicate), synthesized from rice husk was confirmed as a potentially good corrosion inhibitor after studying its electronic properties employing quantum chemical studies. Then the effects of various concentration of inhibitor, temperature and immersion time on the inhibition efficiency of nanosilicate corrosion inhibitor were studied using weight loss studies, electrochemical impedance spectroscopy and potentiodynamic polarization studies. It has been found that with increase in concentration of inhibitor, the corrosion efficiency increases. A maximum of 82 % inhibition efficiency was exhibited at 700 ppm of nanosilicate. Polarization results confirmed that nanosilicate is a mixed-type corrosion inhibitor. Synergistic effects of some chemical inhibitors when used in small amounts with nanosilicate inhibitor showed that ascorbic acid yields the best results.