Abstract
The inhibition of the corrosion of mild steel in hydrochloric acid solution by the extract of Kalmegh (Andrographis paniculata) leaves extract has been studied using weight loss, electrochemical impedance spectroscopy, linear polarization, and potentiodynamic polarization techniques. Inhibition was found to increase with increasing concentration of the extract. The effect of temperature, immersion time, and acid concentration on the corrosion behavior of mild steel in 1 M HCl with addition of extract was also studied. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the metal surface. The adsorption of the molecules of the extract on the mild steel surface obeyed the Langmuir adsorption isotherm. The protective film formed on the metal surface was analyzed by FTIR spectroscopy. The results obtained showed that the extract of Kalmegh (Andrographis paniculata) leaves extract could serve as an effective inhibitor of the corrosion of mild steel in hydrochloric acid media.
Highlights
Acid solutions are commonly used for removal of undesirable scale and rust in metal finishing industries, cleaning of boilers, and heat exchangers
As a contribution to the current interest on environmentally friendly, green, corrosion inhibitors, the present study investigates the inhibiting effect of leaves extract of Kalmegh (Andrographis paniculata), a green inhibitor which is the Kalmegh of the Ayurveda, which is an erect annual herb extremely bitter in taste in each and every part of the plant body
Further increase in extract concentration did not cause any significant change in the performance of the extract
Summary
Acid solutions are commonly used for removal of undesirable scale and rust in metal finishing industries, cleaning of boilers, and heat exchangers. Castor (Ricimus communis) leaves were studied for the corrosion inhibition of mild steel in acid media in addition to the use of herbs such as coriander, hibiscus, anis, black cumin, and garden cress as new type of green inhibitors for acidic corrosion of steel [6,7,8,9,10,11]. As a contribution to the current interest on environmentally friendly, green, corrosion inhibitors, the present study investigates the inhibiting effect of leaves extract of Kalmegh (Andrographis paniculata), a green inhibitor which is the Kalmegh of the Ayurveda, which is an erect annual herb extremely bitter in taste in each and every part of the plant body. Kinetic and activation parameters that govern metal corrosion have been evaluated
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