The role of operational parameters on the uptake of mercury by dithiocarbamate functionalized particles

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.