Removal of gas-phase elemental mercury by iodine- and chlorine-impregnated activated carbons

Lee, Sung Jun; Seo, Yong Chil; Jurng, Jongsoo; Lee, Tai Gyu

doi:10.1016/j.atmosenv.2004.05.043

Cited by 194 publications

(115 citation statements)

References 17 publications

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“…Research by Sung et al indicated that Hg 0 was removed by iodides impregnated on activated carbon when gas phase mercury reacted with the surface halide to form mercury iodides. [28] The conversion of Hg 0 to mercury iodides is thermodynamically favoured in the temperature range 25-227 8C, as indicated by the negative values for the Gibbs free energy of formation for mercury iodides. [29] As shown in Figure 1, an increase in KI loading improved the performance of clay for Hg 0 removal.…”

Section: Effect Of Ki Loadingmentioning

confidence: 99%

“…Chemisorption is facilitated by the formation of mercury compounds when using the iodideimpregnated clay, enhancing the capture of mercury. The reactions [28] can be expressed as follows: It is generally seen that O 2 has a positive influence on the adsorption of Hg 0 by enhancing Hg 0 oxidation. [16] The impregnated KI could provide active sites, forming I-Hg-I bonds.…”

Section: Mercury Adsorption Mechanismsmentioning

confidence: 99%

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Kinetics study on the capture of elemental mercury in flue gas by KI‐impregnated clays

Shen

Chen

et al. 2015

Can J Chem Eng

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To understand the capture of elemental mercury (Hg 0 ) on potassium iodide-impregnated clays, a variety of kinetic models including pseudo-firstorder, pseudo-second-order, Elovich, and intraparticle diffusion models were used to analyze the experimental data and discuss the mechanism. A strong correlation was observed between the pseudo-second-order kinetic model and the experimental data for a range of parameters (KI loading, adsorption temperatures, and O 2 concentrations). This suggests that chemisorption may be a rate-limiting mechanism during the adsorption process on KI clays. Further, the results of the pseudo-first-order model and the intraparticle diffusion model both indicate that mass transfer limitations should not be ignored during the initial stage of adsorption. Thermodynamic investigation shows that the adsorption reaction of Hg 0 on the KI clays is inherently spontaneous and endothermic, corresponding to a process involving both physisorption and chemisorption, and the chemisorption is the dominant adsorption.

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Section: Effect Of Ki Loadingmentioning

confidence: 99%

Section: Mercury Adsorption Mechanismsmentioning

confidence: 99%

Kinetics study on the capture of elemental mercury in flue gas by KI‐impregnated clays

Shen

Chen

et al. 2015

Can J Chem Eng

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“…But their capacity towards a special material like mercury could be significantly increased by impregnation of adsorbent with a material that chemically reacts with, and holds, the mercury (Mohan et al 2000;Anirudhan 2002a, 2002b;Ranganathan and Balasubramanian 2002). Surface chemical modification of adsorbents with the aim of promoting their ion exchange properties for stronger and selective adsorption of special compounds has attained great interest recently (Krishnan and Anirudhan 2008;Nam et al 2003;Rios et al 2003;Lee et al 2004; Mersorb ® Mercury adsorbents 2010). Previous studies have shown that introducing sulfur functionalities onto the surface of adsorbents can improve their mercury uptake capacity (Feng et al 2006;Hsi et al 2002;Wajima et al 2009).…”

Section: Introductionmentioning

confidence: 98%

A comparison on efficiency of virgin and sulfurized agro-based adsorbents for mercury removal from aqueous systems

Asasian

Kaghazchi

2012

Adsorption

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Mercury adsorption by sulfur impregnated adsorbents seems to be one of the most efficient ways for removal of this toxic metal ion from wastewater and atmosphere. The aim of this work was to develop a method for preparation of low-cost sulfurized adsorbent from agricultural wastes; this approach combines two stages of (i) chemical activation with phosphoric acid and (ii) impregnation with powdered sulfur, in one step only. The physico-chemical properties of sulfurized adsorbent (AC-S) were determined with BET, FT-IR, Eschka method and pH PZC measurements, and compared with those of the virgin sample (AC). It was found that sulfurization according to this method can introduce about 8 wt.% sulfur into the structure of adsorbent, in the forms of C-S, S-H, S-S and S=O functional groups. Although during the sulfur introduction processes, a decrease in surface area and micropore volume of the sulfurized adsorbent is to be expected, not only such decrease did not occur in this work, but a large increase in microporosity was seen. Thereupon, both the sulfur functionalities and extended microporosity of AC-S lead to higher capability of this sample for mercury adsorption rather than AC. Finally, the kinetics and equilibrium of mercury adsorption from aqueous solutions were studied for AC and AC-S. Nomenclature BConstant of D-R isotherm related to energy, (mol 2 /J 2 ) C 0 the solute concentration at time t = 0, (mg/l) C t the solute concentration at time t, (mg/l) C e the solute concentration at equilibrium, (mg/l) [in D-R model (g/g)] ePolanyi potential in D-R model E Free energy of adsorption, (J/mol) h (= k 2 q 2 e ) the initial sorption rate, (mg/g min) k 1 Pseudo-first-order adsorption rate constant, (1/min) k 2 Pseudo-second-order adsorption rate constant, (g/mg min) K F Freundlich empirical constant, (mg/g)(mg/l) −1/n K L Langmuir empirical constant (l/mg) K T Equilibrium binding constant corresponding the maximum binding energy, (l/mg) n the exponent in Freundlich isotherm N the number of runs p the number of model's parameters q i,exp the amount of solute adsorbed on the adsorbent observed from the ith run of experiment, (mg/g) q i,calc the amount of solute adsorbed on the adsorbent estimated from the model for corresponding q i,exp , (mg/g) q t the amount of solute adsorbed at time t, (mg/g) q e the amount of solute adsorbed at equilibrium, (mg/g) [in D-R model (mol/g)] q m Monolayer adsorption capacity (in Langmuir model (mg/g)), (in D-R model the theoretical monolayer saturation capacity (mol/g)) RUniversal gas constant, (8.313 J/mol K) R 2 Correlation coefficient RMSE Root mean squared error function t Time, (min) 190 Adsorption (

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“…Lee [45] proposed that chlorine plays an important role in the sorption of mercury in fly ash. Kellie et al [46] suggested that high element chlorine in coal, which can generate high HCl concentration in flue gas and can promote formation of Hg 2+ .…”

Section: Thermal Stability Of Mercury Componentmentioning

confidence: 99%

Thermal Stability and Adsorption of Mercury Compounds in Fly Ash

Zhong¹,

Li²,

Jiang³

2016

TOEFJ

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Fly ashes were collected from five power plants under two loads in China. The ashes were heated at four different temperatures, and mercury speciation was determined based on the release regular pattern of mercury with temperature. The mercury concentration, unburned carbon content and mean ash particle sizes were measured. The correlation of mercury capture and unburned carbon content, mean ash particle sizes were analyzed. Results indicate that the amount of unburned carbon and mercury adsorb is significantly positively correlated in fly ash; the smaller the mean ash particle size, the more mercury particles are captured. There was little HgO and HgSO 4 , and the main form of mercury compounds in fly ash were HgCl 2 and HgS. The high element Cl content can result in high HgCl 2 ratio in particular mercury and element S play an important role in adsorbing mercury.

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Removal of gas-phase elemental mercury by iodine- and chlorine-impregnated activated carbons

Cited by 194 publications

References 17 publications

Kinetics study on the capture of elemental mercury in flue gas by KI‐impregnated clays

Kinetics study on the capture of elemental mercury in flue gas by KI‐impregnated clays

A comparison on efficiency of virgin and sulfurized agro-based adsorbents for mercury removal from aqueous systems

Thermal Stability and Adsorption of Mercury Compounds in Fly Ash

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