Speaker
Abel Eduardo Da Silva Fenta
(University of Aveiro (PT))
Description
Perturbed angular correlation (PAC) spectroscopy experiments were used to study the adhesion of toxic heavy metal ions in aqueous solution to magnetic nanoparticles, to understand the structures and optimum trapping conditions in solutions (water and nitrate). In this work we analyze the results of the radioactive mercury and cadmium isotopes available for PAC, which were implanted in ice. The ice was then used to make solutions with the magnetic nanoparticles. Nanoparticles with different shapes (cubes and spheres) and different coatings were synthesized for study: magnetite (Fe3O4), magnetite coated with silica (SiO2), and also functionalized with dithiocarbamate (DTC) groups, which are expected to provide a stronger mercury uptake. A systematic study of the different conditions finds mainly three different EFG environments for all the different samples. The results are found to be independent of the shape of the particles. To complement the experiments, we performed first-principles density functional calculations are performed for the DTC functional groups in different configurations, to compare electric field gradients with PAC measurements with reference DTC samples. The relaxed theoretical structure is obtained and the binding to Hg is identified in this case. We used the PAW method with the local-density approximation, but the study with more sophisticated approximations (such as B3LIP) is in progress.
Author
Mr
Carlos Amorim
(Universidade de Aveiro)
Co-authors
Abel Eduardo Da Silva Fenta
(University of Aveiro (PT))
Dr
Claudia Maria Batista Lopes
(Universidade de Aveiro)
Joao Martins Correia
(Instituto Superior Tecnico (PT))
Joao Nuno Santos Goncalves
(University of Aveiro (PT))
Tito Trindade
(Universidade de Aveiro)
Vitor Bras De Sequeira Amaral
(University of Aveiro (PT))
