Abstract The corrosion response of mild steel in 0.5 M H2SO4 acid solution in the presence of Moringer oliefera (MO) leaf extract was investigated using gravimetric, electrochemical, and DFT techniques. Gravimetric results indicate that MO exhibits a high inhibition value up to 93.0% when the concentration was 1.5 g/L. Inhibition value in general increased with an increase in concentration of the extracts but decreased with prolonged exposure time and temperature. Analysis of polarization curves indicated that MO extract acted as mixed-type inhibitors. The adsorption process of MO on a mild steel surface in the acid solution fitted the Langmuir isotherm. GC/MS analysis of MO extract revealed the presence of more than 29 active constituents including 9,12-Octadecadienoic acid (Z, Z) methyl ester (28.55%); n-Hexadecanoic acid (11.24%); 9,12,15-Octadecatrienoic acid methyl ester (9.31%), Benzeneacetonitrile, 4-hydroxy-(6.32%), 2-Furancarboxaldehyde,5-(hydroxymethyl)-(5.6%), Heptadecane (4.85%). Quantum chemical calculations were applied on some of the identified constituents to assess their adsorbability on the mild steel surface and the result revealed remarkable high interaction energies.

中文翻译：

---

辣木叶提取物对酸性介质中低碳钢腐蚀的吸附和抑制性能的实验和 DFT 评价

摘要 使用重量分析、电化学和 DFT 技术研究了在存在辣木 (MO) 叶提取物的情况下，低碳钢在 0.5 M H2SO4 酸溶液中的腐蚀响应。重量分析结果表明，当浓度为 1.5 g/L 时，MO 表现出高达 93.0% 的高抑制值。抑制值通常随着提取物浓度的增加而增加，但随着暴露时间和温度的延长而降低。极化曲线分析表明，MO 提取物作为混合型抑制剂。MO在酸性溶液中低碳钢表面的吸附过程符合朗缪尔等温线。MO 提取物的 GC/MS 分析显示存在超过 29 种活性成分，包括 9,12-十八碳二烯酸 (Z, Z) 甲酯 (28.55%)；正十六烷酸 (11.24%); 9,12, 15-十八碳三烯酸甲酯 (9.31%)、苯乙腈、4-羟基-(6.32%)、2-呋喃甲醛、5-(羟甲基)-(5.6%)、十七烷 (4.85%)。量子化学计算应用于一些已识别的成分，以评估它们在低碳钢表面上的吸附性，结果显示出显着的高相互作用能。