摘要
目的探究双咪唑啉(PMA)在CO2/O2环境中对碳钢的缓蚀作用及其与2-巯基乙醇(MAT)复配时的缓蚀性能和机理。方法采用红外光谱对合成的PMA进行表征,运用失重法、电化学测试技术(阻抗谱和极化曲线)和表面形貌分析等手段评价PMA的缓蚀性能,同时探究PMA与MAT复配后的协同缓蚀作用。通过量子化学计算和分子动力学模拟,分析PMA与MAT分子的吸附活性位点和吸附能力。结果失重实验结果表明,CO2/O2环境中添加100 mg/L PMA时,缓蚀率可达66.47%。随MAT浓度的增加,缓蚀效率逐渐提高,当MAT的质量浓度为40 mg/L时,缓蚀率达到最高值(70.38%)。电化学测试结果表明,PMA和MAT复配后,碳钢的腐蚀电位随缓蚀剂浓度的升高而升高,阳极反应受到明显抑制。扫描电镜观察到加入复配缓蚀剂后,碳钢表面光滑,腐蚀深度减小。理论计算结果表明,PMA的活性位点在咪唑啉环上,而MAT的活性位点在硫原子上,二者复配后自由体积分数减小,因此缓蚀效率提高。结论由于PMA在碳钢表面有较强的吸附能力,因此在CO2/O2环境下的缓蚀效果较好,PMA与MAT表现出较好的协同作用,二者复配后,能够更有效地抑制碳钢在CO2/O2环境中的腐蚀。缓蚀机理为PMA在碳钢表面形成一层保护膜,MAT的加入使保护膜更加致密。
To explore the corrosion inhibition performance of bis-imidazoline(PMA)and 2-mercaptoethanol(MAT)in a CO2/O2 environment,infrared spectroscopy,weight loss method,electrochemical measurement technology(impedance spectroscopy and polarization curve)and scanning electron microscope were used to evaluate the inhibition behavior of PMA and MAT on the corrosion of carbon steel.Through quantum chemical calculations and molecular dynamics simulation,the active sites of PMA and MAT are analyzed.The results show that the maximum corrosion inhibition rate is 66.47%when PMA is 100 mg/L in a CO2/O2 environment.As the concentration of MAT increases,the corrosion rate decreases,and the corrosion inhibition efficiency increases.MAT with a concentration of 40 mg/L shows the best corrosion inhibition rate(70.38%),and the electrochemical results are consistent with the weight loss results.Electrochemical tests show that PMA is a mixed corrosion inhibitor,after the addition of MAT,the corrosion inhibition efficiency increases.In the presence of the combined PMA and MAT inhibitor,the corrosion of carbon steel is mainly controlled by the charge transfer process.From the SEM image,corrosion is obviously suppressed after adding PMA and MAT inhibitor.Combined with quantum chemical calculations and molecular dynamics simulation,the active sites of PMA are on the imidazoline rings,while the active sites of MAT are mainly on the sulfur atoms.The corrosion inhibition mechanism is due to that protective film first formed on the surface of the carbon steel,however,the protective film may have defects.After adding MAT,its smaller molecular size can fill the defects in the film,and the active site S atoms are adsorbed on the metal surface to make the film more compact and thus increasing the inhibition efficiency.Due to its strong adsorption capacity and hydrophobic properties,PMA has a good corrosion inhibition effect in CO2/O2 environment,and has a good synergistic effect with 2-mercaptoethanol,which can more effectively inhibit the corrosion process.
作者
张晨峰
扈俊颖
钟显康
郑子奇
耿帅
ZHANG Chen-feng;HU Jun-ying;ZHONG Xian-kang;ZHENG Zi-qi;GENG Shuai(School of Oil and Natural Gas Engineering,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Reservoir Geology and Development Engineering(Southwest Petroleum University),Chengdu 610500,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2020年第11期66-74,共9页
Surface Technology
基金
国家自然科学基金(51501160,51601159)。
关键词
缓蚀剂
咪唑啉
电化学测试
复配
量子化学计算
O2腐蚀
CO2腐蚀
corrosion inhibitor
imidazoline
electrochemical test
compound
quantum chemical calculation
O2 corrosion
CO2 corrosion
