Mercury adsorption and re-emission inhibition from actual WFGD wastewater using sulfur-containing activated carbon
Journal
Environmental Research
Journal Volume
168
Pages
319
Date Issued
2019-01-01
Author(s)
Abstract
© 2018 Elsevier Inc. A series of batch experiments were conducted to obtain the optimal adsorption condition for removing aqueous Hg from actual lime-based wet flue gas desulfurization (WFGD) wastewater with sulfur-containing activated carbon (SAC). The experimental results showed that SAC1 had an average 0.32 μg mg−1 larger aqueous Hg adsorption capacity and 21% larger Hg removal than the CS2-treated SAC1 (i.e., SAC2) in all tested pH values, confirming that greater sulfur content associated with effective sulfur functional group (i.e., elemental S) caused the larger Hg adsorption capacity. Furthermore, as increasing pH from 4 to 7, the Hg adsorption capacity of SAC1 decreased by 22% (i.e., 0.27 μg mg−1). The equilibrium Hg adsorption capacity was well fitted with linear and Freundlich adsorption isotherms. Kinetic simulations showed that both pseudo-second order and Elovich equations could well describe the chemisorption behavior of Hg to SAC1. Thermodynamic parameter calculation confirmed that Hg adsorption by SAC1 was thermodynamically spontaneous and exothermic. Re-emission of gaseous Hg markedly decreased by 88% as SO32- addition increased from 0 to 0.01 mM. Notably, by the addition of SAC1, zero re-emission of gaseous Hg was achieved. These experimental results confirm that the capture of aqueous Hg2+ and the inhibition of gaseous Hg0 re-emission can be successfully and simultaneously achieved in actual WFGD wastewater via the addition of SAC.
A series of batch experiments were conducted to obtain the optimal adsorption condition for removing aqueous Hg from actual lime-based wet flue gas desulfurization (WFGD) wastewater with sulfur-containing activated carbon (SAC). The experimental results showed that SAC1 had an average 0.32 μg mg−1 larger aqueous Hg adsorption capacity and 21% larger Hg removal than the CS2-treated SAC1 (i.e., SAC2) in all tested pH values, confirming that greater sulfur content associated with effective sulfur functional group (i.e., elemental S) caused the larger Hg adsorption capacity. Furthermore, as increasing pH from 4 to 7, the Hg adsorption capacity of SAC1 decreased by 22% (i.e., 0.27 μg mg−1). The equilibrium Hg adsorption capacity was well fitted with linear and Freundlich adsorption isotherms. Kinetic simulations showed that both pseudo-second order and Elovich equations could well describe the chemisorption behavior of Hg to SAC1. Thermodynamic parameter calculation confirmed that Hg adsorption by SAC1 was thermodynamically spontaneous and exothermic. Re-emission of gaseous Hg markedly decreased by 88% as SO3 2- addition increased from 0 to 0.01 mM. Notably, by the addition of SAC1, zero re-emission of gaseous Hg was achieved. These experimental results confirm that the capture of aqueous Hg2+ and the inhibition of gaseous Hg0 re-emission can be successfully and simultaneously achieved in actual WFGD wastewater via the addition of SAC. © 2018 Elsevier Inc.
Subjects
Coal-fired power plant | Mercury | Re-emission | Sulfurized activated carbon | Wet flue gas desulfurization
Coal-fired power plant; Mercury; Re-emission; Sulfurized activated carbon; Wet flue gas desulfurization
SDGs
Other Subjects
activated carbon; adsorbent; functional group; mercury; sulfur; carbon; charcoal; sulfur; activated carbon; adsorption; aqueous solution; chemical reaction; coal-fired power plant; emission; experimental study; mercury (element); pollutant removal; wastewater; wastewater treatment; adsorption kinetics; Article; desorption; desulfurization; flue gas; heavy metal removal; pH; pore size distribution; simulation; thermodynamics; waste water management; wet flue gas desulfurization; adsorption; chemistry; sewage; waste water; Adsorption; Carbon; Charcoal; Mercury; Sulfur; Waste Disposal, Fluid; Waste Water
Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
Type
journal article