Wang Hongyu, Liang Zhipeng, Wang Yiyong, Li Jidong
School of Materials & Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China.
Langmuir. 2024 Oct 8;40(40):21263-21279. doi: 10.1021/acs.langmuir.4c02927. Epub 2024 Sep 27.
In this study, corrosion weight loss experiments were conducted to explore the corrosion-inhibiting properties of a composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater. An investigation was conducted into the electrochemical behavior of EH40 steel in seawater and the mechanism of composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater through an electrochemical test. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and energy-dispersion spectroscopy (SEM-EDS), Fourier transform infrared absorption spectroscopy (FTIR), and contact angle measurements were performed to confirm the mechanism of CMCS and SH as well as their composite corrosion inhibitors at the interface between seawater and EH40 steel. Furthermore, density functional theory (DFT) calculation supports the experimental findings. The results show that CMCS, SH, and their composite inhibitor are a mixed type of corrosion inhibitor that mainly inhibits cathodic reactions and corrosion through the active site blocking mechanisms. Their corrosion inhibition effect increases with the increase of mass concentration, and the composite inhibitor performs better in corrosion inhibition and scale inhibition than the individual inhibitor. When the CMCS mass concentration reaches 100 mg/L and the SH mass concentration reaches 50 mg/L, the corrosion inhibition rate is 74.65%, the corrosion potential shifts by about 47.39 mV, the value increases from 358.6 to 1102.4 Ω·cm, and the value decreases from 177.31 S Ωcm × 10 to 92.672 S Ωcm × 10. CMCS and SH are adsorbed onto the surface of EH40 steel, forming a protective film through the complexation of carboxyl, amino, and other functional groups to inhibit corrosion and prevent the further formation of scale. In addition, synergistic coadsorption occurs between CMCS and SH, and the composite corrosion inhibitor exerts a better effect than the individual corrosion inhibitor.
在本研究中，进行了腐蚀失重实验，以探究由羧甲基壳聚糖（CMCS）和腐植酸钠（SH）组成的复合缓蚀剂在不同浓度下对海水中EH40钢的缓蚀性能。通过电化学测试，研究了EH40钢在海水中的电化学行为以及由羧甲基壳聚糖（CMCS）和腐植酸钠（SH）组成的不同浓度复合缓蚀剂对海水中EH40钢的作用机理。进行了X射线光电子能谱（XPS）、扫描电子显微镜和能谱分析（SEM-EDS）、傅里叶变换红外吸收光谱（FTIR）以及接触角测量，以确认CMCS和SH及其复合缓蚀剂在海水与EH40钢界面处的作用机理。此外，密度泛函理论（DFT）计算支持了实验结果。结果表明，CMCS、SH及其复合缓蚀剂是混合型缓蚀剂，主要通过活性位点阻断机制抑制阴极反应和腐蚀。它们的缓蚀效果随质量浓度的增加而增强，复合缓蚀剂在缓蚀和阻垢方面比单一缓蚀剂表现更好。当CMCS质量浓度达到100 mg/L且SH质量浓度达到50 mg/L时，缓蚀率为74.65%，腐蚀电位偏移约47.39 mV， 值从358.6增加到1102.4 Ω·cm， 值从177.31 S Ωcm×10降低到92.672 S Ωcm×10。CMCS和SH吸附在EH40钢表面，通过羧基、氨基等官能团的络合形成保护膜，从而抑制腐蚀并防止垢的进一步形成。此外，CMCS和SH之间发生协同共吸附，复合缓蚀剂比单一缓蚀剂发挥更好的效果。
