Studies on corrosion inhibition of steel by tannin and coconut husk / Noor Nasuha Noor Ariffin

Studies on the inhibition of steel corrosion by tannin and coconut husk are attempted in this work. Aim of this study is to identify the efficiency inhibition rate at various temperature and concentration of corrosion inhibitor, adsorption behaviour and occurrence of corrosion on steel. In order to investigate, the recovered coconut husk and tannin were used to protect stainless steel coupons from corroding in an acidic setting. Acetone was utilised to successfully dissolve natural alternatives such as coconut husk and tannin powder. The capacity to suppress stainless steel corrosion at various temperatures was weight loss and immersion test at concentrations of 0.5, 1.0, 1.5, 2.0, and 2.5 g/L and 0.5, 1.0, 1.5, 2.0, and 2.5 g/L coconut husk and tannin respectively. The findings demonstrated that when both corrosion inhibitor concentration and inhibition effectiveness rose, the rate of corrosion reduced at various temperatures. The Langmuir model and Temkin model was determined to be the best models to describe the interaction of tannin inhibitor with the active sites on stainless steel surface by isotherm adsorption. The morphology of the stainless steel altered following the addition of corrosion inhibitors, according to the optical microscope study. A blue-black tint on the surface of the stainless steel hinted at the need to produce ferric tannate as a surface preserver. As a result, Tannin performed for the highest efficiency with 84.38% at 40 °C. Meanwhile, Coconut husk shows the greatest efficiency with 77.50% at 40 °C. Last but not least, corrosion inhibitors derived from coconut husk and tannic acid are more effective against stainless steel when subjected to 1 M HCl at low temperatures. This study revealed that lower temperature has showed good inhibition properties with presence of corrosion inhibitors to protect the stainless steel from corroding.