Natural marañon nutshell extract was obtained by mechanical compression. The extract was combined with ethanol and a nonionic surfactant, and it was labeled as EES. The EES inhibitor effect on S135 carbon steel, exposed to a simulated marine-coastal environment (SME), was deduced by mass loss measurement, adsorption isotherm, electrochemical measurements, and surface analysis. The Langmuir adsorption isotherm suggested that a monolayer of the marañon extract was attached by physical–chemical interaction with the steel surface. The increase in the protective efficiency of the adsorbed EES inhibitor was ascribed to the gain of the surface coverage as a function of the inhibitor concentration. It was considered an antioxidant activity of the inhibitor, attributed mostly to the Fe-ion capture by anacardic acid and the posterior ion chelation. This fact was collaborated by the negative zeta potential of the marañon nutshell extract, added to the SME. Electrochemical impedance spectroscopy (EIS) diagrams revealed that the steel polarization resistance (Rp) increased as a function of the inhibitor concentration, while the thickness (d) of the Fe-oxide layer was reduced to ≈0.50 nm.
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机译：天然 marañon nutshell 提取物是通过机械压缩获得的。将提取物与乙醇和非离子表面活性剂结合，标记为 EES。通过质量损失测量、吸附等温线、电化学测量和表面分析，推导出暴露于模拟海洋-沿海环境 （SME） 的 S135 碳钢的 EES 抑制作用。Langmuir 吸附等温线表明，单层 marañon 提取物是通过与钢表面的物理化学相互作用连接的。吸附的 EES 抑制剂保护效率的增加归因于表面覆盖率的增加，这是抑制剂浓度的函数。它被认为是抑制剂的抗氧化活性，主要归因于漆树酸捕获 Fe 离子和后离子螯合。这一事实与 SME 中添加的 marañon nutshell 提取物的负 zeta 电位相辅相成。电化学阻抗谱 （EIS） 图显示，钢极化电阻 （Rp） 随抑制剂浓度的增加而增加，而 Fe 氧化物层的厚度 （d） 减小到 ≈0.50 nm。
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