Hidalgo Juan, Hidalgo Luis, Serrano Aguiar Carlos Diego, García Madroñero Daniela Belén, Galambos Ildiko, Vilasó-Cadre Javier Ernesto, Reyes-Domínguez Ivan Alejandro, Brânzanic Adrian M V, Ignat Nicoleta, Turdean Graziella Liana
University of Pannonia, Soós Ernő Water Technology Research and Development Center, Zrínyi Miklós St. 18, H-8800, Nagykanizsa, Hungary.
Escuela Superior Politécnica de Chimborazo, Research Institute of Mechanical Engineering, Materials Laboratory, Panamericana Sur km 11/2, EC-06001, Riobamba, Ecuador.
Langmuir. 2025 Apr 15;41(14):9406-9421. doi: 10.1021/acs.langmuir.5c00224. Epub 2025 Apr 4.
The plant, known as Tara, was used to prepare a green corrosion inhibitor solution using hot solid-liquid (Soxhlet extraction, Tara-SE) and cold solid-liquid extraction (maceration, Tara-ME) techniques. Their anticorrosive protection ability was tested on mild steel in a 0.1 M HNO solution. The chemical content of the extracts was examined by FTIR and Vis spectrophotometry, and the surface morphology of the mild steel was studied by SEM. The effect of different concentrations of the green inhibitors on the mild steel in acidic solutions was determined by weight loss (WL), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) measurements, allowing the estimation of the inhibitor efficiency (IE%). Values of IE ranging from 90.73 to 97.38% for Tara-1000-SE and from 85.3 to 96.05% for Tara-1000-ME were obtained by WL, PP, and EIS experiments. The thermodynamic assessments at different temperatures and concentrations were studied using different adsorption isotherm models (i.e., Langmuir, Freundlich, Temkin, Flory-Huggins, and El-Awady). The best results were confirmed by the best values of the simultaneous and reduced-Chi-squared statistical parameters. The Gibbs free energy of adsorption (Δ) value suggests that the inhibitor is physically absorbed on the metal surface. The adsorption mechanism, studied by classical and computational quantum mechanical modeling methods, evidenced strongly developed interactions between gallic acid adsorbate (i.e., the principal component of the Tara extract) and differently cleaved Fe surfaces. Moreover, density functional theory (DFT) based electron localization function (ELF) analysis assessed the nature of these interactions as being characteristic of physisorption processes. The results showed superior inhibition performance of the hot solid-liquid extraction (Soxhlet extract, SE) compared to the cold solid-liquid extraction techniques (maceration, ME), although, according to all research techniques, both extracts demonstrated a satisfactory level of anticorrosive protection for the mild steel exposed to acid conditions.
这种名为塔拉的植物被用于采用热固液（索氏提取法，塔拉 - SE）和冷固液提取法（浸渍法，塔拉 - ME）制备一种绿色缓蚀剂溶液。在0.1 M硝酸溶液中对低碳钢测试了它们的防腐保护能力。通过傅里叶变换红外光谱（FTIR）和可见分光光度法检测提取物的化学成分，并通过扫描电子显微镜（SEM）研究低碳钢的表面形态。通过失重（WL）、动电位极化（PP）和电化学阻抗谱（EIS）测量确定了不同浓度的绿色缓蚀剂在酸性溶液中对低碳钢的影响，从而估算缓蚀效率（IE%）。通过WL、PP和EIS实验，塔拉 - 1000 - SE的IE值范围为90.73%至97.38%，塔拉 - 1000 - ME的IE值范围为85.3%至96.05%。使用不同的吸附等温线模型（即朗缪尔、弗伦德里希、坦金、弗洛里 - 哈金斯和埃尔 - 阿瓦迪）研究了不同温度和浓度下的热力学评估。通过同时和简化的卡方统计参数的最佳值证实了最佳结果。吸附的吉布斯自由能（Δ）值表明缓蚀剂在金属表面物理吸附。通过经典和计算量子力学建模方法研究的吸附机制证明了吸附质没食子酸（即塔拉提取物的主要成分）与不同解理的铁表面之间有强烈的相互作用。此外，基于密度泛函理论（DFT）的电子定位函数（ELF）分析评估了这些相互作用的性质为物理吸附过程的特征。结果表明，与冷固液提取技术（浸渍法，ME）相比，热固液提取（索氏提取物，SE）具有优异的缓蚀性能，不过，根据所有研究技术，两种提取物对暴露于酸性条件下的低碳钢都表现出令人满意的防腐保护水平。
