基于分子动力学的钠离子与纳米二氧化硅表面的相互作用过程模拟  

Simulation of Interaction Process between Sodion and the Surface of Nano Silicon Dioxide Based on Molecular Dynamics

作　　者：张凤娟 张磊[2] 吕振虎 麦尔耶姆古丽·安外尔 余维初[3] 王牧群 董景锋 庄为杰 ZHANG Fengjuan;ZHANG Lei;LYU Zhenhu;MELYAMGULI·Anwaier;YUWeichu;WANG Muqun;DONG Jingfeng;ZHUANG Weijie(Engineering Technology Research Institute,Xinjiang Oilfield Company of CNPC,Karamay,Xinjiang 834000,P R of China;Province Key Laboratory of Theory and Technology of Petroleum Exploration and Development,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,P R of China;School of Chemical and Environmental Engineering,Changjiang University,Jingzhou,Hubei 434023,P R of China)

机构地区：[1]中国石油新疆油田分公司工程技术研究院,新疆克拉玛依834000 [2]中国地质大学油气勘探开发理论与技术湖北省重点实验室,湖北武汉430074 [3]长江大学化学与环境工程学院,湖北荆州434023

出　　处：《油田化学》2024年第3期491-497,共7页Oilfield Chemistry

基　　金：国家自然科学基金“基于微观流变力学原理的单个凝胶微球长期变形与运移机制研究”(项目编号52204054)。

摘　　要：认识盐水中的Na^(+)对纳米SiO_(2)的作用过程,可为优化纳米SiO_(2)在石油开采领域的应用参数提供依据。以无定形纳米SiO_(2)粒子为研究对象,构建了一种既有饱和稳定的硅醇基团,又有脱质子化的硅醇基团的纳米SiO_(2)粒子模型。通过分子模拟方法,刻画了Na^(+)在纳米SiO_(2)表面的运移特征、扩散行为、对氢键的影响以及体系中的相互作用能。结果表明,在纳米SiO_(2)-NaCl溶液体系中,当Na^(+)运移至距纳米SiO_(2)粒子表面6.540A时,短程力开始起作用;当Na^(+)运移至距纳米SiO_(2)粒子表面2~3A时,二者发生电荷交换,Na^(+)产生振荡运动。在NaCl质量浓度为3 g/L时,Na^(+)与水分子主要进行水合作用,形成稳定的溶剂化层,Na^(+)与纳米SiO_(2)粒子之间的作用力弱,Na^(+)更易在溶液中扩散。随着NaCl质量浓度增至7 g/L,Na^(+)突破溶剂化层,和水分子一起被吸附到纳米SiO_(2)粒子的表面,发生电荷置换,Na^(+)的运移能力减弱,扩散系数由1.39×10^(-4)A^(2)/ps下降至3.75×10^(-5)A^(2)/ps,斯特恩层的厚度由0.88A下降至0.72A,亥姆霍兹层的厚度由0.64A下降至0.20A,纳米SiO_(2)与Na^(+)之间的相互作用能由-14 000 kcal/mol变为-22 000 kcal/mol,纳米SiO_(2)的稳定性逐渐被破坏。Na^(+)与纳米SiO_(2)粒子的静电相互作用是影响纳米SiO_(2)粒子表面性质的主要作用力,氢键和范德华力则是次要作用力。研究结果可为纳米SiO_(2)材料在油气开采领域及其他相关行业的应用提供基础理论认识。It can more effectively regulate the parameters of application of nano SiO_(2) in the field of oil production by understanding the interaction process of Na^(+)on the surface of nano SiO_(2) in saline water.In this paper,the amorphous nano SiO_(2) particles was taken as an object of study,so that a nano SiO_(2) particle model with both saturated stable silanol groups and deprotonated silanol groups was constructed.By using the molecular dynamics simulation experiments,this paper studied the interaction process between nano-SiO_(2) particles and Na^(+)with different concentrations,including transportation,diffusion,recombination of hydrogen bonds,and the interaction energy.The results showed that in the system of nano-SiO_(2) and NaCl solution,when Na^(+)migrated to a distance of 6.540Åaway from the surface of nano SiO_(2) particles,the short-range force began to affect the movement of Na^(+).When Na^(+)migrated to a distance of 2—3Åaway from the surface of nano SiO_(2) particles,the charge exchange occurred between Na^(+)and the surface of nano SiO_(2) particles,resulting in an oscillation motion of Na^(+).At a NaCl concentration of 3 g/L,most Na^(+)underwent hydration with water molecules,which could form a stable solvation layer.The interaction between Na^(+)and nano SiO_(2) particles was weak,so Na^(+)was more likely to diffuse in the solution.As the concentration of NaCl increased to 7 g/L,Na^(+)could break through the solvation layer.And then Na^(+)along with water molecules could be adsorbed on the surface of nano-SiO_(2) particles.The migration ability of Na^(+)was weakened,the thickness of the double electric layer on the surface of nano-SiO_(2) particles was narrowed,the interaction energy between nano-SiO_(2) and Na^(+)was enhanced,and then the stability of nano-SiO_(2) was gradually destroyed.The diffusion coefficient of Na^(+)decreased from 1.39×10^(-4)A^(2)/ps to 3.75×10^(-5)A^(2)/ps.The thickness of the Stern layer on the surface of nano-SiO_(2) decreased from 0.88Åto 0.72Å.The thickness of

关 键 词：分子模拟 纳米SiO_(2) 钠离子 水合离子 表面作用 

分 类 号：TE357[石油与天然气工程—油气田开发工程] TE39