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

• One-step method for the surface modification of magnetite and silica sorbents.
• Efficient and fast uptake of Hg by both dithiocarbamate functionalized sorbents.
• Hg levels in solution ∼100-folds lower than the guideline value for drinking water.
• The degree of sorbents functionalization only affected the kinetics of the process.
• Confirmation of the strong affinity of dithiocarbamate functional groups toward Hg.

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 μg/L to values circa 100 times lower than the guideline value for drinking water quality (1 μg/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.

Figure optionsDownload as PowerPoint slide