International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
Vol. 12, No. 8, 2015, pp. 2511-2522
Bioline Code: st15237
Full paper language: English
Document type: Research Article
Document available free of charge
International Journal of Environment Science and Technology, Vol. 12, No. 8, 2015, pp. 2511-2522
© Copyright 2015 - International Journal of Environment Science and Technology
Sulfurized activated carbons and their mercury adsorption/ desorption behavior in aqueous phase|
Asasian, N. & Kaghazchi, T.
Sulfurized activated carbons (SACs) are of the
most recent forms of modified sorbents with high affinity
toward mercury. The adsorption/desorption behavior of
SACs has not been studied in detail in liquid phases. The
study was carried out with the aim of recognition of
similarities and differences in the properties and performances
of SACs and activated carbons (ACs) exposing to
aqueous-phase mercury. In this study, three different sulfurizing
agents including dimethyl disulfide (DMDS), elemental
sulfur (S), and sulfur dioxide (SO2) were tested for
AC sulfurization (each under the optimal conditions).
Sulfurization with DMDS at room temperature led to the
formation of elemental sulfur and sulfide/disulfide on the
AC surface; however, sulfurization at higher temperatures
with SO2 and powdered S resulted in the formation of more
stable organic forms such as thiophene and oxidized sulfur.
The equilibrium mercury adsorption capacity of AC–
DMDS was so larger than AC and other SACs. On the
other hand, the largest surface area drop and consequently
the slowest mercury adsorption rate belonged to this sample.
However, AC–S and AC–SO2 led to moderate increase
in mercury equilibrium adsorption capacity; they showed
several advantages resulted from their extended porosities
and more stable sulfur functionalities. The more accelerated
adsorption especially at initial stages of contact in
batch modes and negligible entry of sulfur compounds into
the treating wastewater were of their important advantages.
Mercury desorption was also studied and compared using
several acidic and potassium halide solvents. The possibility
of applicability of SACs in consecutive mercury
adsorption/desorption cycles was also investigated.
Adsorption; Desorption; Mercury; Sulfurized activated carbon; Wastewater treatment
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