The concentration effect of Tradescantia spathacea (T. spathacea) as corrosion inhibitor of API 5L X52 steel in 0.5 M of H2SO4 was studied here through electrochemical and gravimetric techniques. To achieve it, samples of the material were prepared to be submitted to each of the tests. Results from electrochemical impedance spectroscopy (EIS) showed that there was an optimum concentration of the inhibitor in which is reached the maximum inhibition efficiency, displaying the best inhibition characteristics for this system with a maximum inhibition of 89% by using 400 ppm. However, the efficiency decreased until 40% when the temperature was increased to 60°C. Potentiodynamic polarization curves (PDP) revealed that some of the present compounds of T. spathacea may affect anodic and cathodic process, so it can be classified as a mix-type corrosion inhibitor for API 5L X52 in sulfuric acid. Also, this compound followed an adsorption mechanism; this can be described through a Frumkin isotherm with an adsorption standard free energy difference (ΔG°) of −56.59 kJmol−1. Metal surface was studied through scanning electron microscope, results revealed that by adding inhibitor, the metal surface is protected; also, they evidenced low damages compared with the surface with no inhibitor. Finally, Tradescantia spathacea inhibited the corrosion process with 82% efficiency.

中文翻译：

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紫露草对 API 5L X52 管线钢在酸性介质中的缓蚀作用

浓度效应紫露草 (T. spathacea)作为 API 5L X52 钢在 0.5 M H 中的缓蚀剂2所以4在这里通过电化学和重量分析技术进行了研究。为了实现这一目标，准备了材料样品以提交给每项测试。电化学阻抗谱(EIS)结果表明，存在一个达到最大抑制效率的最佳抑制剂浓度，显示出该体系的最佳抑制特性，在400 ppm时最大抑制率为89%。然而，当温度升高至 60°C 时，效率下降至 40%。动电位极化曲线（PDP）表明，目前的一些化合物芥兰可能会影响阳极和阴极过程，因此可归类为硫酸中 API 5L X52 的混合型缓蚀剂。此外，该化合物遵循吸附机制；这可以通过吸附标准自由能差 (ΔG°) 为 -56.59 kJmol 的弗鲁姆金等温线来描述−1。通过扫描电镜对金属表面进行研究，结果表明，通过添加缓蚀剂，对金属表面起到了保护作用；此外，与没有抑制剂的表面相比，它们的损坏程度较低。最后，紫露草抑制腐蚀过程的效率为 82%。