Abstract:
We analyze potentiometric and conductimetric measurements simultaneously performed on Electric Double-Layer Magnetic Fluid based on cobalt ferrite nanoparticles, in order to obtain the pH-dependence of the particle surface charge density. We propose a mechanism for the charging of the particle surface. This model considers the ferrofluid solution as a mixture of strong and weak diprotic acids. We show how an exact analytical treatment involving proton transfer between the particle surface and the bulk solution allows the construction of a speciation diagram of the charged superficial sites. The saturation value of the superficial density of charge is found to be equal to 0.326 ± 0.065 C m-2.
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Received 9 May 2001 and Received in final form 17 July 2001
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Campos, A., Tourinho, F., da Silva, G. et al. Nanoparticles superficial density of charge in electric double-layered magnetic fluid: A conductimetric and potentiometric approach. Eur. Phys. J. E 6, 29–35 (2001). https://doi.org/10.1007/s101890170025
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DOI: https://doi.org/10.1007/s101890170025