Corrosion in carbon steel units of chemical, petrochemical and oil and gas plants poses safety and economic concerns. The goal of our study is to investigate the corrosion inhibition effectiveness of an environmentally benign surfactant, namely sodium lauroyl lactylate (SLL), in comparison to sodium cocoyl glutamate (SCG) and sodium dodecyl sulfate (SDS). The corrosion of carbon steel in 1 M HCl was markedly inhibited by 0.05 and 0.1 M of the anionic surfactant SLL, as determined from weight loss over 96 h, at ambient conditions. X-ray photoelectron spectroscopy (XPS) showed that SLL adsorbed at the carbon steel surface, forming a protective film that decreased corrosion. Scanning electron microscopy (SEM) showed that carbon steel surfaces immersed in 1 M HCl for 96 h had an etched appearance without SLL, whereas they retained their smoothness with 0.1 M SLL. Electrochemical impedance spectroscopy (EIS) measurements confirmed that SLL passivated carbon steel surfaces, markedly increasing the polarization resistance R_p from ≈95 to ≈20,694 Ω cm² over a 12 h period. In contrast, without SLL, R_p decreased from ≈92 to ≈12 Ω cm². These results demonstrate for the first time that the environmentally friendly surfactant SLL is an efficient corrosion inhibitor in extreme environments such as 1 M HCl solutions. Dissimilar to SLL, SCG and SDS were not effective in inhibiting corrosion.

中文翻译：

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三种阴离子表面活性剂在酸性环境中的缓蚀对比研究

化学、石化和石油和天然气工厂的碳钢装置的腐蚀带来了安全和经济问题。我们研究的目的是研究环境友好型表面活性剂，即月桂酰乳酸钠 (SLL) 与椰油酰谷氨酸钠 (SCG) 和十二烷基硫酸钠 (SDS) 相比的缓蚀效果。碳钢在 1 M HCl 中的腐蚀被 0.05 和 0.1 M 的阴离子表面活性剂 SLL 显着抑制，如在环境条件下 96 小时的重量损失所确定的。X 射线光电子能谱 (XPS) 显示 SLL 吸附在碳钢表面，形成减少腐蚀的保护膜。扫描电子显微镜 (SEM) 表明，在 1 M HCl 中浸泡 96 小时的碳钢表面具有没有 SLL 的蚀刻外观，而他们用 0.1 M SLL 保持了平滑度。电化学阻抗谱 (EIS) 测量证实 SLL 钝化了碳钢表面，显着增加了极化电阻R _p在 12 小时内从 ≈95 到 ≈20,694 Ω cm ^{2 。}相反，在没有 SLL 的情况下，R _p从 ≈92 降低到 ≈12 Ω cm ²。这些结果首次表明，环保型表面活性剂 SLL 在极端环境（例如 1 M HCl 溶液）中是一种有效的缓蚀剂。与 SLL 不同，SCG 和 SDS 在抑制腐蚀方面无效。