The risk of mild steel corrosion during the acid cleaning process can be reduced by using an aqueous extract of Euphorbia prostrata plant. The efficiency of Euphorbia prostrata plant extract for corrosion inhibition was explored by applying weight loss analysis, SEM, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, and DFT studies on mild steel corrosion in 1 M H2SO4. This extract contains β-sitosterol, Campesterol, Stigmasterol, Cholesterol, Apigenin, Luteolin, Apigenin-7-glucoside, Luteolin-7-glucoside, Gallic acid, and Ellagic acid. The availability of multiple bonds and heteroatoms in the phytochemicals of this extract are primarily responsible for its anticorrosive properties. The plant extract solution has a higher ∆Ha in the presence of an inhibitor (47.67 kJ/mol) than in the absence of an inhibitor (8.59 kJ/mol) suggesting that the metal is better protected. Furthermore, from quantum chemical studies, we compared the effectiveness of the phytochemicals present in the extract. At 1500 mg/L, the maximal inhibition efficiency of 96.23% in 1 M H2SO4 solution was obtained.
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Keywords: Euphorbia prostrata; Electrochemical impedance spectroscopy; Quantum chemical calculations; Green corrosion inhibitors; Economic productivity