resumo
The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m(3)/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m(3)/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents' Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results.
palavras-chave
HEAVY-METAL IONS; EFFICIENT REMOVAL; NATURAL-WATERS; SORPTION; HG2+; GEL; NANOPARTICLES; EQUILIBRIUM; ADSORBENT; ISOTHERM
categoria
Environmental Sciences & Ecology
autores
Lopes, CB; Figueira, P; Tavares, DS; Lin, Z; Daniel-da-Silva, AL; Duarte, AC; Rocha, J; Trindade, T; Pereira, E
nossos autores
Ana Luísa Daniel da Silva
Investigador Principal
Carlos Manuel Silva
Professor associado
Cláudia Batista Lopes
Investigador Auxiliar
Daniela Soraia dos Santos Tavares
Estudante de doutoramento
João Rocha
Prof. Catedrático
Paula Figueira
Técnico de Laboratório
Tito Trindade
Professor Catedrático
Zhi Lin
Investigador PrincipalGrupos
G1 - Materiais Porosos e Nanossistemas
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
Projectos
agradecimentos
The authors thank Fundacao para a Ciencia e a Tecnologia (FCT; PTDC/CTM-NAN/120668/2010), FSE and POPH for funding. One of the authors, C.B. Lopes, thanks Fundacao para a Ciencia e Tecnologia (FCT) for a Post-Doc grant (SFRH/BPD/45156/2008). FCT and FEDER are also thanked financing projects PEst-C/MAR/LA0017/2011 and PEst-C/CTM/LA0011/2011.