A series of novel gemini surfactants containing hydroxyl group have been synthesized including 1,3-bis(dodecyl dimethyl ammonium chloride)-2-propanol,1,3-bis(myristyl dimethyl ammonium chloride)-2-propanol,1,3-bis(hexadecyl dimethyl ammonium chloride)-2-propanol,and 1,3-bis(octadecyl dimethyl ammonium chloride)-2-propanol,designated as n-3OH-n (n=12,14,16,18,respectively).The corrosion inhibition for carbon steel in brine solution containing H2S and CO2 was investigated using weight loss method,potentiodynamic polarization,and electrochemical impedance spectroscopy (EIS).The results showed that the inhibition efficiencies (IEs) obtained from all of the methods employed demonstrated a clear trend,with the IEs of the gemini surfactants ranked as 14-3OH-14＞12-3OH-12＞16-3OH-16＞18-3OH-18.Among them,14-3OH-14 and 12-3OH-12 acted as excellent corrosion inhibitors with IE values greater than 95％ at an additive concentration of 35 mg· L-1.Potentiodynamic polarization curves clearly revealed that the gemini surfactants are mixed-type inhibitors which preferentially inhibit the anodic corrosion process.Adsorption of the synthesized gemini surfactants n-3OH-n (n=12,14,16) onto a carbon steel surface obeys the Langmuir adsorption isotherm and they exhibit a mixed physical and chemical adsorption.An adsorption model was proposed to elucidate the inhibition mechanism of gemini surfactants.%合成了一系列含有羟基的双子表面活性剂:1,3-双(十二烷基二甲基氯化铵)-2-丙醇(12-3OH-12),1,3-双(十四烷基二甲基氯化铵)-2-丙醇(14-3OH-14),1,3-双(十六烷基二甲基氯化铵)-2-丙醇(16-3OH-16)和1,3-双(十八烷基二甲基氯化铵)-2-丙醇(18-3OH-18).采用静态失重法、极化曲线和交流阻抗技术研究了其在H2S/CO2腐蚀环境中对L360钢的缓蚀作用.结果表明,三种研究方法取得的结论是一致的,缓蚀效果为14-3OH-14＞12-3OH-12＞16-3OH-16＞18-3OH-18.其中,12-3OH-12和14-3OH-14都表现出很好的缓蚀效果,在35 mg·L-1的较低浓度下缓蚀率就达95％以上.极化曲线测试结果表明n-3OH-n (n=12,14,16,18)型双子表面活性剂是一种以阳极抑制为主的混合型缓蚀剂.除n=18外,其它三种双子表面活性剂n-3OH-n (n=12,14,16)在L360钢表面的吸附服从朗缪尔等温线,并且属于物理和化学混合吸附.提出了一个用来解释双子表面活性剂在H2S/CO2溶液中缓蚀机理的吸附模型.
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