Peach pomace hydroalcoholic extract (PPE) was evaluated as “green” corrosion inhibitor in neutral media of 0.5 M NaCl solution. Gas chromatography mass spectrometry (GC–MS) and High performance liquid chromatography (HPLS) analysis was used to identify the main components of PPE. Total phenolic (TPC) and total flavonoid compounds (TFC) were assayed. Weight assessment, potentiodynamic polarisation tests, and polarization resistance method, were employed to explore the inhibition properties of PPE. The maximum corrosion inhibition efficiency (about 88%) was obtained in the presence of 800 ppm PPE after 48 h immersion. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis were used to characterize the protective film. Results derived from GC–MS spectra explained the complicated formation of product oxidized/condensation products/products of the conjugates between the components of the extract in neutral medium. The FT-IR system affirmed the presence of protective film in the steel surface. The results of gravimetric and electrochemical methods research revealed that in the attendance of the peach pomace extract with the immersion time progress up to 48 h, the inhibition capacity of inhibitor was promoted. The phenomenon of prolonged action “48 h” and the influence of the time of film formation on its effectiveness were explained. Quantum chemical parameters calculated by Density functional theory (DFT) were correlated with the experimental results. The results from this study could contribute to better understanding of the mechanism increasing the inhibitory effect of plant extracts with increasing exposure time.

Graphic Abstract

中文翻译：

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桃渣渣提取物作为新型低成本，高性能绿色缓蚀剂，用于NaCl溶液中钢的腐蚀：实验和理论研究

在0.5 M NaCl溶液的中性介质中，桃果渣水醇提取物（PPE）被评估为“绿色”缓蚀剂。气相色谱质谱（GC-MS）和高效液相色谱（HPLS）分析用于鉴定PPE的主要成分。测定了总酚（TPC）和总黄酮化合物（TFC）。重量评估，电位动力学极化测试和极化电阻方法被用来探索PPE的抑制性能。在浸入48小时后，在800 ppm PPE的存在下，可获得最大的缓蚀效率（约88％）。使用扫描电子显微镜（SEM）和原子力显微镜（AFM）分析来表征保护膜。来自GC-MS光谱的结果解释了在中性介质中，提取物各组分之间的结合物氧化/缩合产物/产物的复杂形成。FT-IR系统确认钢表面存在保护膜。重量法和电化学法的研究结果表明，随着浸泡时间的延长，桃渣提取物的浸出时间延长至48 h，其抑制能力得到了提高。解释了“ 48 h”长时间作用的现象以及成膜时间对其有效性的影响。密度泛函理论（DFT）计算的量子化学参数与实验结果相关。

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