Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/3240
Título: Dynamics and heterogeneity of Pb(II) binding by SiO 2 nanoparticles in an aqueous dispersion
Autor: Goveia, D.
Pinheiro, J. P.
Milkova, V.
Rosa, A. H.
Van Leeuwen, H. P.
Data: 2011
Editora: American Chemical Society
Citação: Goveia, D.; Pinheiro, J. P.; Milkova, V.; Rosa, A. H.; Van Leeuwen, H. P. Dynamics and heterogeneity of Pb(II) binding by SiO 2 nanoparticles in an aqueous dispersion, Langmuir, 27, 12, 7877-78, 2011.
Resumo: ABSTRACT: Pb(II) binding by SiO2 nanoparticles in an aqueous dispersion was investigated under conditions where the concentrations of Pb2þ ions and nanoparticles are of similar magnitude. Conditional stability constants (log K) obtained at different values of pH and ionic strength varied from 4.4 at pH 5.5 and I = 0.1Mto 6.4 at pH 6.5 and I = 0.0015 M. In the range of metal to nanoparticle ratios from 1.6 to 0.3, log K strongly increases, which is shown to be due to heterogeneity in Pb(II) binding. For an ionic strength of 0.1 M the Pb2þ/SiO2 nanoparticle system is labile, whereas for lower ionic strengths there is loss of lability with increasing pH and decreasing ionic strength. Theoretical calculations on the basis of Eigen-type complex formation kinetics seem to support the loss of lability. This is related to the nanoparticulate nature of the system, where complexation rate constants become increasingly diffusion controlled. The ion binding heterogeneity and chemodynamics of oxidic nanoparticles clearly need further detailed research.
Peer review: yes
URI: http://hdl.handle.net/10400.1/3240
DOI: http://dx.doi.org/10.1021/la2008182
ISSN: 0743-7463
Aparece nas colecções:FCT2-Artigos (em revistas ou actas indexadas)

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