Biopolymers such as polydopamine and polyserotonin are effective corrosion inhibitors for the acidic-induced corrosion of steel. Despite the excellent corrosion inhibition activity of these compounds, they are not cost-effective and readily available in a large scale. In this study, for the first time, a cheap and easy methodology was followed for obtaining the modified Nettle extract including the oxidized/dimerized bio-active products such as serotonin and histamine. The Nettle extract (NTE) and oxidized Nettle extract components (ONTE) were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), UV-visible spectroscopy, and thermal gravimetric analysis (TGA). The NTE was oxidized under the alkaline condition at an ambient temperature. Finally, 600 ppm NTE and ONTE were separately added to 1 mol L⁻¹ HCl solution to reduce the steel corrosion rate. The corrosion inhibition activity of the utilized inhibitors was assessed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. The surface features were examined by SEM, atomic force microscope (AFM), and water contact angle test. The obtained results displayed that the ONTE inhibitor resulted in the higher inhibition efficiency than the NTE. The maximum inhibition efficiency, i.e. 93.40%, was obtained in the case of the acidic solution inhibited by 600 ppm ONTE after 1.5 h. Results of the polarization test and surface analyses proved the ONTE inhibitor components adsorption on the active metal sites, especially on the anodic areas. In studying of effects of temperature on the corrosion rate of mild steel the positive effect of ONTE on the mild steel corrosion mitigation was noticed. It was shown that the adsorption of the inhibitor on the metal surface obeyed the Langmuir isotherm in both physisorption and chemisorption forms.

生物聚合物（如聚多巴胺和聚羟色胺）是有效的缓蚀剂，用于钢的酸性诱导腐蚀。尽管这些化合物具有出色的腐蚀抑制活性，但它们并不具有成本效益，并且易于大规模获得。在这项研究中，第一次，一种廉价，简便的方法被用于获得修饰的荨麻提取物，其中包括氧化/二聚的生物活性产物，如5-羟色胺和组胺。的荨麻提取物（NTE）和氧化荨麻通过傅里叶变换红外光谱（FT-IR），扫描电子显微镜（SEM），紫外可见光谱和热重分析（TGA）对提取物成分（ONTE）进行表征。NTE在环境温度下于碱性条件下被氧化。最后，将600 ppm NTE和ONTE分别添加到1 mol L ^-1 HCl溶液中以降低钢的腐蚀速率。通过电化学阻抗谱（EIS）和电位极化（PDP）技术评估了所用抑制剂的缓蚀活性。通过SEM，原子力显微镜（AFM）和水接触角测试检查表面特征。所得结果表明，ONTE抑制剂比NTE具有更高的抑制效率。最大抑制效率即93.40％，在1.5小时后通过600ppm的ONTE抑制酸性溶液的情况下获得。极化测试和表面分析的结果证明，ONTE抑制剂组分吸附在活性金属部位，特别是在阳极区域。在研究温度对低碳钢腐蚀速率的影响时，注意到ONTE对缓和低碳钢腐蚀的积极作用。结果表明，抑制剂在金属表面上的吸附均以物理吸附和化学吸附形式服从朗缪尔等温线。