Study on the Extract of Raphanus Sativus L as Green Corrosion Inhibitor for Q235 Steel in HCl Solution

In this work, the extract of Raphanus sativus L (Sinapine thiocyanate, Inhi-ST) as green inhibitor was extracted and isolated by the dried and powdered semen raphanin from Raphanus sativus L. After the target green inhibitor isolated, it was characterized by ESI-MS, H-1 and C-13-NMR. Meanwhile, the corrosion inhibition of Q235 steel (QS) by Inhi-ST in HCl solution was evaluated using weight loss and potentiodynamic polarization measurement. The study results indicate that Inhi-ST is an effective green corrosion inhibitor for QS corrosion in HCl solution, the green corrosion inhibitor is a mixedtype inhibitor, and the inhibition efficiency increase with Inhi-ST concentration increasing, while which decrease with HCl concentration, temperature and storage time increasing. In addition, the adsorption of Inhi-ST on QS follows Langmuir isotherm, which is the mixed adsorption involving both chemisorption and physisorption.