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Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System

Abstract Details

2014, Master of Science, Ohio State University, Civil Engineering.
In this study, we investigated the heteroaggregation behavior of silver nanoparticles with clay minerals (montmorillonite and illite) in neutral pH solutions. Bare and Tween-coated silver nanoparticles with a nominal diameter of 60.9 ± 0.5 nm were synthesized following established methods. Illite (IMt-2) and montmorillonite (SWy-2) were purchased from the Clay Mineral Society (Indiana) and pretreated to obtain monocationic (Na-clay) and dicationic (Ca-clay) suspensions. Aggregation was monitored as a function of electrolyte concentration in both homo- and heteroaggregation scenarios by measuring the change in hydrodynamic diameter as a function of time using dynamic light scattering (DLS). Our results did not show significant differences in the stability of binary component systems of bare silver nanoparticle and clays at pH 7 when compared to the single particle systems of clay or silver at the same pH. All six combinations of bare silver nanoparticles and clays in binary systems (i.e., f-f, f-e, e-e, NP-f, NP-e, NP-NP) were barrier-controlled (i.e., high electrolyte concentration is needed to overcome the energy barrier to form aggregates). We attribute this to weakly charged or negatively charged clay edges (e), negatively charged silver nanoparticles (AgNPs), as well as permanently negatively charged basal plane surfaces (f) of the clays at pH 7. The results suggest that the binary system of montmorillonite/illite and bare silver nanoparticles can be treated as a single component system of clays under the experimental conditions studied, and the fate of silver nanoparticles in aqueous system may be controlled by their heteroaggregation of clay minerals. However, under neutral conditions, the stability of the binary system was greatly increased when bare silver nanoparticles were changed to Tween-coated ones. The CCCs of the binary system contain Tween-AgNPs are all above 100mM in either NaCl, NaNO3, or CaCl2, and in some systems such as Ca-montmorillonite with Tween-AgNPs, the CCCs cannot even be determined in all the electrolyte solutions. The adsorption of Tween 80 on the clay surface was proposed to explain the changes among different clays and electrolytes. The present results showed that coated silver nanoparticles are more mobile than uncoated ones, and their interactions with clay minerals will be greatly affected by the existence of polymer/surfactant in the medium.
John Lenhart (Advisor)
Paula Mouser (Committee Member)
Ethan Kubatko (Committee Member)
153 p.

Recommended Citations

Citations

  • Liu, J. (2014). Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408927952

    APA Style (7th edition)

  • Liu, Jibin. Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System. 2014. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1408927952.

    MLA Style (8th edition)

  • Liu, Jibin. "Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408927952

    Chicago Manual of Style (17th edition)