Speaker
Vitor Bras de Sequeira Amaral
(Universidade de Aveiro, Department of Physics, CICECO, Portugal)
Description
Water pollution by trace heavy metals (such as mercury, cadmium) is a serious environmental and public problem. The development of efficient new materials and clean-up technologies for removing those metals from water to within the legal admissible concentrations is urgent. In the last few years, a new type of eco-nanomagnets composed of amorphous SiO2 shells coating magnetite (Fe3O4) particles functionalized at the surface with dithiocarbamate (DTC) groups was developed [1], taking advantage of the high stability of the chelates formed between the DTC groups and metal ions. To improve their perfomance, the understanding of the surface coordination chemistry in these nanomaterials is crucial.
We have started a study with 119Hg isotope made on eco-nanomagnets using the perturbed angular correlation (PAC) technique to probe the coordination environment of the ions [Letter of intent I81] through the Electric Field Gradient. We present the results of experiments performed in aqueous solution containing bare and functionalized nanoparticles, of different sizes and with different uptakes of Hg ion, to enable the determination of fractions of different local environments associated and also to conclude about the kinetics of the adsorption and desorption processes of the metal cations at the nanoparticles surfaces.
[1] Penka I. Girginova et al, J. Colloid and Interface Science, 345, 234 (2010)
Author
Vitor Bras de Sequeira Amaral
(Universidade de Aveiro, Department of Physics, CICECO, Portugal)
Co-authors
Ana Luísa Daniel da Silva
(Universidade de Aveiro, Department of Chemistry, CICECO, Portugal)
Armandina Maria Lima Lopes
(Universidade de Lisboa, Centro de Física Nuclear, Portugal)
Célia Sousa
(Universidade do Porto, Faculdade de Ciências, IFIMUP, Portugal)
Eduarda Pereira
(Universidade de Aveiro, Department of Chemistry, CICECO, Portugal)
Joao Guilherme Martins Correia
(ITN, Sacavém, Portugal and ISOLDE-CERN)
Joao Nuno Santos Gonçalves
(Universidade de Aveiro, Department of Physics, CICECO, Portugal)
João Pedro Araújo
(Universidade do Porto, Faculdade de Ciências, IFIMUP, Portugal)
Lars Hemmingsen
(Faculty of Life Sciences, University of Copenhagen, Denmark)
Manuel Silva Martins
(Universidade de Aveiro, Department of Chemistry, CICECO, Portugal)
Paula Figueira
(Universidade de Aveiro, Department of Chemistry , CICECO, Portugal)
Tito Trindade
(Universidade de Aveiro, Department of Chemistry, CICECO, Portugal)
