Ion specific surface charge density of SBA-15 mesoporous silica

Andrea Salis*, Drew F. Parsons, Mathias Boström, Luca Medda, Brajesh Barse, Barry W. Ninham, Maura Monduzzi

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    86 Citations (Scopus)

    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 ionsurface dispersion interactions and ion hydration.

    Original languageEnglish
    Pages (from-to)2484-2490
    Number of pages7
    JournalLangmuir
    Volume26
    Issue number4
    DOIs
    Publication statusPublished - 16 Feb 2010

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