SBA-15 介孔硅的离子比表面电荷密度。

Ion specific surface charge density of SBA-15 mesoporous silica.

机构信息

Department of Chemical Sciences, University of Cagliari-CNBS and CSGI, Cittadella Universitaria, S.S. 554 Bivio Sestu, 09042 Monserrato, Italy.

出版信息

Langmuir. 2010 Feb 16;26(4):2484-90. doi: 10.1021/la902721a.

DOI:10.1021/la902721a

PMID:19831379

Abstract

Potentiometric titrations were used to estimate the surface charge density of SBA-15 mesoporous silica in different salt solutions. It was found that surface charge depends both on cation type, following a Hofmeister series (Cs(+) < Guanidinium(+) < K(+) < Na(+) < Li(+)), and on salt concentration (in the range 0.05-1 M). The surface charge series is reproduced by theoretical calculations performed using a modified Poisson-Boltzmann equation that includes ionic dispersion forces with ab initio ion polarizabilities and hydrated ions. The hydration model assigns an explicit hydration shell to kosmotropic (strong hydrated) ions only. The Hofmeister series appears to be due to the combination of ion-surface dispersion interactions and ion hydration.

摘要

电位滴定法被用于估计不同盐溶液中 SBA-15 介孔硅的表面电荷密度。结果表明，表面电荷既取决于阳离子类型，遵循豪夫迈斯特序列（Cs(+) < 胍 (+) < K(+) < Na(+) < Li(+)），也取决于盐浓度（在 0.05-1 M 范围内）。表面电荷序列是通过使用修正的泊松-玻尔兹曼方程进行的理论计算重现的，该方程包括具有从头算离子极化率和水合离子的离子色散力。水合模型仅将等渗（强水合）离子分配给明确的水合壳。豪夫迈斯特序列似乎是由于离子-表面色散相互作用和离子水合的结合。