电解质离子对硬脂酸Langmuir膜稳定性影响机理  

Mechanism of Effect of Electrolyte Ions on Stability of Langmuir Monolayer of Stearic Acid

作　　者：何宇廷 刘月田 柴汝宽 HE Yuting;LIU Yuetian;CHAI Rukuan(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《西安石油大学学报（自然科学版）》2023年第1期77-84,共8页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家科技重大专项(2017ZX05032004-002);国家重点基础研究发展计划(973计划)(2015CB250905);国家自然基金项目(51374222);中国石油重大科技专项(2017E-0405);中国石化重点科技项目(P18049-1)。

摘　　要：利用Langmuir膜实验从微观尺度解释电解质离子对油水界面膜特征的影响规律和机理。通过表面压力-平均分子面积等温曲线研究不同电解质类型与浓度对界面膜强度的影响,从压缩能变化特征角度分析气—液、液—固阶段亥姆赫兹自由能增加速度不同的原因,以黏弹性变化分析油水界面流变特征。研究发现:电解质离子类型对油水界面膜特征有重要影响,影响程度Mg^(2+)>Na^(+)>SO_(4)^(2-),其原因是由于阳离子与硬脂酸阴离子基团—COO^(—)形成金属阳离子-络合物使表面膜结构更加稳定,且阳离子表面电荷密度越高膜强度越高。同时,电解质浓度对油水界面膜特征同样有重要影响,随着电解质离子浓度的增加,硬脂酸在油水界面的排列逐渐紧密,直至临界浓度;继续增加,紧密排列的硬脂酸分子膜逐渐破坏。The characteristics and mechanism of the influence of electrolyte ions on the characteristics of oil-water interface membraneare explained from the microscopic scale using Langmuir film experiment.The influence of different electrolyte types and concentrations on the strength of interface membrane was studied through the surface pressure--average molecular area isotherm curve.The reasons for the different increase rates of Helmholtz free energy in gas-liquid and liquid-solid phases were analyzed by the characteristics of compression energy changes, and the rheological characteristics of oil-water interface were analyzed by viscoelastic changes.It is found that the type of electrolyte ion has an important influence on the characteristics of oil-water interface membrane, and the influence is Mg^(2+),Na^(+),SO_(4)^(2-)in descending order.The reason is that cation and stearic acid anion group —COO^(-)form metal cation complex to make the surface membrane structure more stable, and the higher the cation surface charge density, the higher the membrane strength.The electrolyte concentration also has an important influence on the characteristics of oil-water interface membrane.With the increase of electrolyte ion concentration, stearic acid arranged closely at the oil-water interface until the critical concentration.The tightly arranged stearic acid molecular membrane was gradually destroyed as the electrolyte ion concentration further increase.

关 键 词：智能水驱 油水界面 硬脂酸 LANGMUIR膜 电解质离子 

分 类 号：TE344[石油与天然气工程—油气田开发工程]