abstract
Sorbents based on silica and silica coated magnetite particles have been functionalized with dithiocarbamate groups, aiming at the uptake of mercury. The uptake capacity of the synthesized materials were evaluated systematically for variable operational parameters including degree of functionalization, sorption time, sorbent dose, and initial Hg(II) concentration. Removal efficiencies of 99.6-99.9% were achieved in 8-24 h, regardless the sorbent dose, type of substrate and degree of functionalization. All sorbents were able to decrease an initial Hg(II) concentration of 50 mu g/L to values circa 100 times lower than the guideline value for drinking water quality (1 mu g/L), with the additional advantage of magnetic separation by application of an external magnetic field, in the case of the silica coated magnetite. The high capacity of these materials for Hg(II) uptake from water is attributed to their functionalization due to the strong complexation of the mercury ions and dithiocarbamate groups. The modelling of the kinetic and the equilibrium results was well described by common kinetic and equilibrium equations. (C) 2014 Elsevier B.V. All rights reserved.
keywords
HEAVY-METAL IONS; MAGNETITE PARTICLES; AQUEOUS-SOLUTIONS; REMOVAL; ADSORPTION; WATER; EQUILIBRIUM; ISOTHERM; SORPTION; SOLIDS
subject category
Engineering
authors
Tavares, DS; Lopes, CB; Daniel-da-Silva, AL; Duarte, AC; Trindade, T; Pereira, E
our authors
Ana Luísa Daniel da Silva
Principal Researcher
Cláudia Batista Lopes
Assistant Researcher
Daniela Soraia dos Santos Tavares
PhD Student
Tito Trindade
Full professorProjects
acknowledgements
This work was financed by national funding from FT (Fundacao para a Ciencia e a Tecnologia) through the project PTDC/CTM-NAN/120668/2010, by FEDER through program COMPETE, and through FCT/FEDER in the frame of projects Pest-C/MAR/LA0017/2013 and Pest-C/CTM/LA0011/2013 C.B. Lopes also thanks FCT for the Post-DOC grant SFRH/BD/45156/2008.