Overlook of carbonaceous adsorbents and processing methods for elemental mercury removal
Overlook of carbonaceous adsorbents and processing methods for elemental mercury removal
Carbon letters. 2014. Oct, 15(4): 238-246
Copyright © 2014, Korean Carbon Society
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
  • Published : October 31, 2014
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About the Authors
Kyong-Min Bae
Department of Chemistry, Inha University, 253 Nam-gu, Incheon 402-751, Korea
Byung-Joo Kim
R&D Division, Korea Institute of Carbon Convergence Technology, 817 Duckjin-gu, Jeonju 561-844, Korea
Soo-Jin Park
Department of Chemistry, Inha University, 253 Nam-gu, Incheon 402-751, Korea

People have been concerned about mercury emissions for decades because of the extreme toxicity, persistence, and bioaccumulation of methyl Hg transformed from emitted Hg. This paper presents an overview of research related to mercury control technology and identifies areas requiring additional research and development. It critically reviews measured mercury emissions progress in the development of promising control technologies. This review provides useful information to scientists and engineers in this field.
1. Introduction
Mercury is considered one of the most toxic metals due to its volatility, persistence, bioaccumulation and health impacts on human beings [1 - 8] . On April 19, 2012, the US Environment Protection Agency (EPA) issued the national standard Final Mercury and Air Toxics Standards for the control of mercury, acid gases, and other toxic pollution from coal-fired power plants. On Dec. 20, 2012, the U.S. EPA finalized a specific set of adjustments to Clean Air Act standards. The mercury emission limitation in the 2012 final standards is 2.0−3.0 tons/year for the boilers that need to meet emission limits in the 2012 final standards [9 - 12] .
There are three forms of mercury in the flue gas from coal-fired power plants: elemental mercury (Hg 0 ), oxidized mercury (Hg 2+ ) and particle bound mercury (Hg P ). Particulatebound mercury refers to the mercury adsorbed onto residential particulate, it can be collected using current air pollution control devices (APCD) such as electrostatic precipitator (ESP) and fabric filter (FF). Oxidized mercury can be captured efficiently using wet scrubbers since it is water-soluble. Conversely, elemental mercury is very difficult to be removed because of its high vapor pressure and low water solubility. Thus, control of elemental mercury should be the focus of mercury emissions from coal-fired power plants since it is the most difficult species to be eliminated [13 - 25] .
As one of the most important materials, carbon materials have attracted a lot of attention for their potential applications as automobiles, aerospace, defense, sports, gas storage, electrodes, filler, and catalyst supports [26 - 41] . Especially, porous materials (including activated carbons, zeolites, and alumina powders) are useful materials for gas adsorption and storage [42 - 49] . Adsorption, especially using activated carbon (AC) as adsorbent, is currently the most widely used technology for hazardous gas removal from the incineration flue gases [50 - 61] . As for the sorbent injection technique, activated carbons are injected into the flue gas right before it enters the electrostatic precipitators or bag house filters. In a fixed-bed type system, the flue gas passes through a packed tower with a specified depth of the AC particles. The system is designed to increase the contact time between mercury and the sorbents (AC) without causing a pressure drop to increase. Many researchers have studied ways to further improve AC’s mercury removal efficiency. The recent studies [62 - 65] show better mercury removal by sulfur-impregnated AC than virgin ones. Because, when physisorption is a dominant process upon using virgin AC, chemisorption is facilitated by the formation of HgS when using the sulfurimpregnated AC. In addition, sulfur impregnation improved the mercury removal efficiency by changing the surface area and pore size distribution which were affected by impregnation temperature and sulfur-to-carbon ratio.
In spite of the high mercury removal efficiency, using sulfur-impregnated AC usually results in high operating costs. Hence, various materials with lower operating costs have been tested as possible alternatives to AC. In a recent study, Kim et al . [66] prepared copper-coated porous carbonaceous materials (Cu/PC) using an electroless plating. They determined a strong correlation between the Cu 2 O/Cu ratio and the mercury removal properties of Cu-coated porous carbonaceous materials. Also, Bae et al . [67] prepared metaldecorated activated carbons and evaluated the efficiency of elemental mercury removal as a function of the metal species. Song et al . [68] studied hydrogen bromide for its removal of elemental mercury in a laboratory scale.
In this paper, we review the processing methods and the various materials for elemental mercury.
2. Adsorbents
- 2.1. Chemically treated carbon sorbents
Sasmaz et al . [69] studied the speciation of Hg adsorbed on brominated activated carbon sorbents in the presence of air. It was found that Hg 0 is oxidized at the brominated carbon surfaces at both 30°C and 140°C. The oxidation state of adsorbed Hg is found to be Hg 2+ , and coordinated to two Br atoms with no detectable bonding between Hg and O.
Yao et al . [70] investigated the sulfur treated activated carbon fibers (ACF) for gas phase elemental mercury removal. The incorporation of sulfur groups appears to facilitate the oxidation process of Hg and subsequent bonded with oxidized Hg, resulting in higher Hg capacities. Sulfide groups appear to be more effective for mercury removal than sulfate groups since the lone pairs of electrons of sulfide groups are responsible for interaction with mercury, or at least as a point of initial attachment. Additionally, physical properties associated with sorbent properties such as surface area, pore volume and pore size also affect mercury adsorption performance. For example, as stated earlier micropores are responsible for Hg adsorption while mesopores serve as transport route. Authors best results for mercury uptake is 11–15 mg/g C with sulfur content between 6 and 7 wt.% for NaSH–ACF and S(v)–ACF ( Fig. 1 ).
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Mercury uptake capacities with sulfur-treated samples based on the mass of coating [70].
Tian et al . [71] studied elemental mercury removal by activated carbon impregnated with CeO 2 . The influencing factors researched include loading values changing from 1 wt.% to 10 wt.% and adsorption temperature changing from 30 to 200°C. The results show that CeO 2 impregnation particularly with 3 wt.% CeO 2 -impregnated greatly enhanced the AC adsorption ability for elemental mercury. The experiment under a wide range of temperature implied that both chemisorption and physisorption played an important role in the removal of Hg 0 . 3% CeO 2 /AC showed the best performance at 100°C ( Fig. 2 ).
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Hg0 removal efficiency of CeO2, AC and ameliorated AC at 60°C [71].
Our previous works [66 , 67] , Fig. 3 shows the elemental mercury adsorption behavior of Cu/PCs. Elemental mercury adsorption of all Cu-ACs occurred at a level higher than that of the as-received sample. The efficiency increased with increasing plating time up to Cu-15 and then decreased in the Cu-25 despite the similar specific surface areas and total pore volumes. In conclusion, there is a strong correlation between the Cu 2 O/Cu ratio and the mercury removal properties of Cucoated porous carbonaceous materials [66] . Fig. 4 shows the elemental mercury adsorption behaviors of metal/activated carbon hybrid materials. Based on the experimental results, elemental mercury adsorption of all metal/ACs occurred at a level higher than that of the as-received sample. It is thus concluded metal plating (Cu and Ni) on carbon surfaces can be a good method for enhance elemental mercury adsorption [67] .
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Elemental mercury removal efficiency of the Cu/PC as a function of the plating time; (a) breakthrough time for the as-received sample, (b) breakthrough time for Cu-25, (c) breakthrough times for Cu-5 and Cu-10, (d) breakthrough time of Cu-15. Breakthrough means 90% filter performance for elemental mercury [66].
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Elemental mercury adsorption of metal/activated carbon hybrid materials as a function of plating time. [67].
- 2.2. Petroleum coke
Tao et al . [72] reported activated coke impregnated with cerium chloride used for elemental mercury removal from simulated flue gas. The effects of CeCl3 loading values, reaction temperatures and individual flue gas components including O 2 , NO, SO 2 and H 2 O (g) on Hg 0 removal efficiency of AICC samples were investigated. Results showed that Hg 0 removal efficiency of AC was significantly enhanced by CeCl 3 . The optimal CeCl 3 loading value and reaction temperature was around 6% and 170°C, respectively. Additionally, the experiment results of effects of flue gas components on Hg 0 removal efficiencies showed that when O 2 was present in the flue gas, NO and SO 2 were observed to promote Hg 0 oxidation. However, in the absence of O 2 , SO 2 showed an insignificant inhibition on Hg 0 removal. Furthermore, when H 2 O was added into the flue gas, the Hg 0 removal capacity had a slight declination ( Figs. 5 and 6 ).
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SEM micrographs of (A) virgin AC, (B) AICC2, (C) AICC4, (D) AICC6, and (E) AICC10 [72].
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Effects of individual flue gas components on Hg0 oxidation and capture efficiency of AICC6 (all gases balanced with N2) [72].
- 2.3. Zeolites
Kim et al . [73] studied elemental mercury removal for some kinds of porous materials (MCM-41, SBA-15, AC). AC showed high elemental mercury adsorption of 295.2 μg/m 3 . However, comparing to two types of mesopore materials (SBA-15 and MCM-41), the mercury vapor adsorption was higher in SBA-15 as SBA-15 has a higher micropore volume fraction than MCM-41.We can conclude this work by stating that mercury vapor adsorptions rates can be optimized in terms of the specific surface area and micropore fraction ( Fig. 7 ).
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Elemental mercury adsorption of ACs, SBA-15, and MCM-41 [73].
- 2.4. Fly ash
Xu et al . [74] reported mercury removal from coal combustion flue gas by modified fly ash. Fly ash shows unique adsorption activity for mercury removal. Incompletely burned carbon is an important factor for improving mercury removal efficiency. In particular, the C–M bond, which is formed via the reaction of C and Ti, Si and other elements, may improve the oxidation of mercury. High specific surface areas and small pore diameters are beneficial for mercury removal efficiency.
3. Processing technologies
The control of mercury emissions from coal-fired boilers is achieved via existing controls used to remove particulate matter (PM), sulfur dioxide (SO 2 ), and nitrogen oxides (NOx). This includes capture of particulate-bound mercury in PM control equipments such as electrostatic precipitator (ESP), fabric filter (FF), and soluble mercury compounds in wet FGD systems. The use of selective catalytic reduction (SCR) of NOx control enhances the concentration of soluble mercury compounds in flue gas and results in increased mercury removal in the downstream wet FGD system [75 - 81] .
ESP is significantly less effective than FF, because there is less contact between gaseous mercury and fly ash in ESPs. A FF can be very effective for mercury removal from coals, which is one of the reasons that more and more FF units are being installed recently. However, this FF-only configuration only represents small percentage of (5−10% of the U.S.) coal burning capacity. Mercury in its oxidized state (Hg 2+ ) is highly watersoluble and thus would be expected to be captured efficiently in wet FGD systems. However, over 80% of total mercury stays in elemental form, and easily escapes from wet FGD system [77] .
- 3.1. Catalytic oxidation
It is well-known that the elemental form Hg 0 , which is the main component of mercury in gas phase, is very hard to be removed due to their high volatility and low solubility in water. However, the oxidized mercury Hg 2+ has much higher solubility in water, and thus the oxidation of Hg 0 to Hg 2+ followed by the ESP and/or wet scrubbing processes became a promising method for mercury removal [77] .
Kong et al . [82] studied catalytic oxidation of gas-phase elemental mercury by nano-Fe 2 O 3 . The results showed that Hg 0 could be oxidized by active oxygen atom on the surface of nano- Fe 2 O 3 as well as lattice oxygen in nano-Fe 2 O 3 . Among the factors that affect Hg 0 oxidation by nano-Fe 2 O 3 , bed temperature plays an important role. More than 40% of total mercury was oxidized at 300°C, however, the test temperature at 400°C could cause sintering of nano-catalyst, which led to a lower efficiency of Hg 0 oxidation ( Figs. 8 and 9 ).
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SEM images of iron oxide nano catalyst after Hg0 oxidation at 300°C (a) and 400°C (b) [82].
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Hg0 oxidation efficiency with different bed temperature (10% O2) [82].
Liu et al . [83] investigated catalytic oxidation of gas-phase mercury over Co/TiO 2 catalysts prepared by sol–gel method. Experimental results revealed that the optimal loading of Co was 7.5%, which yielded more than 90% oxidation efficiency within the temperature range of 120–330°C. The high activity was mainly attributed to the enrichment of well dispersed Co 3 O 4 ( Fig. 10 ).
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Co-oxidation of NO and mercury oxidation under experiment condition; [Hg0]=180 μg/m2, balanaceed gas = N2, flow rate=700 mL/min, GHSV=105,000 h-1, O2=3%, HCl=29 ppm, NO=300 ppm. [83].
Xu et al . [84] reported elemental mercury oxidation and adsorption on magnesite powder modified by Mn at low temperature. The results show that removal efficiency of Hg 0 is obviously improved due to the activity of Mn, and 10 wt.% Mn/MgO adsorbent exhibits high removal efficiency of Hg 0 , which reached about 82% at l20°C. The results show amorphous MnO 2 and O 2 play a crucial role in the removal of Hg 0 from the simulated gas ( Figs. 11 and 12 ).
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Removal efficiency of elemental mercury by Mn/MgO with differernt Mn loading at temperature range (80-150°C) in air; carrier and balance gas N2:O2 vol% about 8%; inlet elemental mercury concentration= 30-60 ppb; GHSV=27,000 h-1 [84].
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Effect of O2 (O2 vol% about 6%) on elemental removal efficiency at 120°C; carrier and balance gas N2; inlet elemental mercury conenctration=30-60 ppb; GHSV=27,000 h-1 [84].
- 3.2. Selective catalytic reduction
The selective catalytic reduction (SCR) of NOx with NH 3 has been an efficient and widely used technology to control NOx emissions in coal-fired flue gas. The recent investigations have demonstrated that the catalyst used in the SCR process, especially V 2 O 5 –WO 3 /TiO 2 catalyst, showed the highest catalytic activity in Hg 0 oxidation reaction [85] . In addition, the activity component V 2 O 5 played an important role in promoting Hg 0 oxidation efficiency on the surface of catalyst [86] .
Chen et al . [85] studied elemental mercury oxidation and slip ammonia abatement with SCR-Plus catalysts. Authors reported that the SO 2 and NH 3 tolerance in the coal-fired flue with low levels of HCl was excellent. The Ru/SCR that was doped with Mo facilitated the activation of HCl. In addition, this treatment also achieved high NOx removal and NH3 decomposition efficiency with excellent N 2 selectivity. Therefore, the Mo-Ru/SCR catalyst appears to have potential for synchronously removing Hg 0 and slip ammonia from industrial coal-fired flue gas ( Figs.13 and 14 ).
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The conception of the SCR-Plus and its integration with the typical SCR catalyst [85].
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A comparison of the Hg0 catalytic oxidation with various catalysts and with 5 ppm HCl and 500 ppm SO2. The compositions in the gas were 4% O2 and N2. the Hg0 concentration in the gas was approximately 200 (±10) μg/m3. The space velocity (SV) was approximately 5.9×105 h-1. The temperature was 623K [85].
Rallo et al . [87] investigate the SCR effects in terms of mercury oxidation and the impact of acid gases on mercury oxidation in a SCR system. It was found that the mercury oxidation across the plate type catalyst investigated can vary from 0% to 70%. Results showed that by increasing the temperature above 320°C, the mercury oxidation rates decreased and reached zero for 420°C. In contrast, the reaction rate of NOx-reduction by NH 3 and SO 3 -formation by SO 2 -oxidation are strongly accelerated by increase in temperature ( Fig. 15 ).
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Effect of SO2 concentration on mercury oxidation rate with the plate type catalyst at 380±C; AV=19 m/h; LV=1.7 m/s and recovery rates of total Hg [87].
4. Conclusions
In this study, we reviewed the adsorbents and processing methods for elemental mercury control. Several factors potentially affect the efficiency of a sorbent to remove mercury from flue gas. These include the mercury speciation in flue gas; the flue gas composition; process conditions; sorbent characteristics; and the presence of other active additives.
Additional research is needed to identify the mercury compounds that are formed and to verify capture mechanisms. Engineering development is also needed to improve sorbent dispersion and optimize gas–solid contact time.
This subject is supported by INHA UNIVERSITY Research Grant and the Carbon Valley Project of the Ministry of Knowledge Economy, Korea.
Watters JI , Mason JG 1956 Investigation of the Complexes of Mercury (II) with Ethylenediamine Using the Mercury Electrode1 J Am Chem Soc 78 285 -    DOI : 10.1021/ja01583a010
Du W , Yin L , Zhuo Y , Xu Q , Zhang L , Chen C 2014 Catalytic Oxidation and Adsorption of Elemental Mercury over CuCl2-ImpregnatedSorbents Ind Eng Chem Res 53 582 -    DOI : 10.1021/ie4016073
Won JH , Lee TG 2012 Estimation of total annual mercury emissions from cement manufacturing facilities in Korea Atmos Environ 62 265 -    DOI : 10.1016/j.atmosenv.2012.08.035
Krishnan SV , Gullett BK 1994 Sorption of elemental mercury by activated carbons Environ Sci Technol 28 1506 -    DOI : 10.1021/es00057a020
Kolker A , Senior CL , Quick JC 2006 Mercury in coal and the impact of coal quality on mercury emissions from combustion systems Appl Geochem 21 1821 -    DOI : 10.1016/j.apgeochem.2006.08.001
Skodras G , Diamantopoulou I , Pantoleontos G , Sakellaropoulos GP 2008 Kinetic studies of elemental mercury adsorption in activated carbon fixed bed reactor J Hazard Mater 158 1 -    DOI : 10.1016/j.jhazmat.2008.01.073
Qiao S , Chen J , Li J , Qu Z , Liu P , Yan N , Jia J 2009 Adsorption and Catalytic Oxidation of Gaseous Elemental Mercury in Flue Gasover MnOx/Alumina Ind Eng Chem Res 48 3317 -    DOI : 10.1021/ie801478w
Cho JH , Eom Y , Lee TG 2014 Pilot-test of the calcium sodium phosphate (CNP) process for the stabilization/solidification of variousmercury-contaminated wastes Chemosphere 117 374 -    DOI : 10.1016/j.chemosphere.2014.07.080
Zhuang Z , Yang Z , Zhou S , Wang H , Sun C 2014 Synergistic photocatalytic oxidation and adsorption of elemental mercury by carbon modified titanium dioxide nanotubes under visible light LED irradiation Chem Eng J    DOI : 10.1016/j.cej.2014.05.010
Karatza D , Lancia A , Prisciandaro M , Musmarra D , Celso GM 2013 Influence of oxygen on adsorption of elemental mercury vaporsonto activated carbon Fuel 111 485 -    DOI : 10.1016/j.fuel.2013.03.068
Mullett M , Pendleton P , Badalyan A 2012 Removal of elemental mercury from Bayer stack gases using sulfur-impregnated activatedcarbons Chem Eng J 211-212 133 -    DOI : 10.1016/j.cej.2012.09.098
Tan Z , Sun L , Xiang J , Zeng H , Liu Z , Hu S , Qiu J 2012 Gas-phase elemental mercury removal by novel carbon-based sorbents Carbon 50 362 -    DOI : 10.1016/j.carbon.2011.08.036
An J , Shang K , Lu N , Jiang Y , Wang T , Li J 2014 Performance evaluation of non-thermal plasma injection for elemental mercury oxidationin a simulated flue gas J Hazard Mater 268 237 -    DOI : 10.1016/j.jhazmat.2014.01.022
Hu C , Zhou J , Luo Z , Cen K 2011 Oxidative Adsorption of Elemental Mercury by Activated Carbon in Simulated Coal-Fired Flue Gas Energy Fuels 25 154 -    DOI : 10.1021/ef101100y
Ie IR , Hung CH , Jen YS , Yuan CS , Chen WH 2013 Adsorption of vaporphaseelemental mercury (Hg0) and mercury chloride (HgCl2) with innovative composite activated carbons impregnated with Na2Sand S0 in different sequences Chem Eng J 229 469 -    DOI : 10.1016/j.cej.2013.06.059
Zhang A , Zheng W , Song J , Hu S , Liu Z 2014 Cobalt manganese oxides modified titania catalysts for oxidation of elemental mercury at lowflue gas temperature Chem Eng J 236 29 -    DOI : 10.1016/j.cej.2013.09.060
Senior CL , Johnson SA 2005 Impact of carbon-in-ash on mercury removal across particulate control devices in coal-fired power plants Energy Fuels 19 859 -    DOI : 10.1021/ef049861
Cho JH , Eom Y , Lee TG 2014 Stabilization/solidification of mercury-contaminated waste ash using calcium sodium phosphate(CNP) and magnesium potassium phosphate (MKP) processes J Hazard Mater 278 474 -    DOI : 10.1016/j.jhazmat.2014.06.026
Wu C , Cao Y , Dong Z , Cheng C , Li H , Pan W 2010 Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler J Environ Sci 22 277 -    DOI : 10.1016/S1001-0742(09)60105-4
Pudasainee D , Kim JH , Yoon YS , Seo YC 2012 Oxidation, reemission and mass distribution of mercury in bituminous coal-fired powerplants with SCR, CS-ESP and wet FGD Fuel 93 312 -    DOI : 10.1016/j.fuel.2011.10.012
Liu X , Wang S , Zhang L , Wu Y , Duan L , Hao J 2013 Speciation of mercury in FGD gypsum and mercury emission during the wallboard production in China Fuel 111 621 -    DOI : 10.1016/j.fuel.2013.03.052
Stergaršek A , Horvat M , Frkal P , Stergaršek J 2010 Removal of Hg0 fromflue gases in wet FGD by catalytic oxidation with air-An experimental study Fuel 89 3167 -    DOI : 10.1016/j.fuel.2010.04.006
Lee KJ , Lee TG 2012 A review of international trends in mercury management and available options for permanent or long-term mercurystorage J Hazard Mater 241-242 1 -    DOI : 10.1016/j.jhazmat.2012.09.025
Lee TG , Hyun JE 2006 Structural effect of the in situ generated titaniaon its ability to oxidize and capture the gas-phase elementalmercury Chemosphere 62 26 -    DOI : 10.1016/j.chemosphere.2005.04.048
Zeng H , Jin F , Guo J 2004 Removal of elemental mercury from coal combustion flue gas by chloride-impregnated activated carbon Fuel 83 143 -    DOI : 10.1016/S0016-2361(03)00235-7
Park SJ , Jeong HJ , Nah C 2004 A study of oxyfluorination of multiwalled carbon nanotubes on mechanical interfacial properties ofepoxy matrix nanocomposites Mater Sci Eng A 385 13 -    DOI : 10.1016/j.msea.2004.03.041
Rodrigues G , de Paiva J , do Carmo JB 2014 Recycling of carbon fibers inserted in composite of DGEBA epoxy matrix by thermal degradation Polym Degrad Stabil 109 50 -    DOI : 10.1016/j.polymdegradstab.2014.07.005
Park SJ , Donnet JB 1998 Anodic surface treatment on carbon fibers: Determination of acid-base interaction parameter between two unidentical solid surfaces in a composite system J Colloid InterfaceSci 206 29 -    DOI : 10.1006/jcis.1998.5672
Kim S , Park SJ 2007 Effect of acid/base treatment to carbon blackson preparation of carbon-supported platinum nanoclusters ElectrochimActa 52 3013 -    DOI : 10.1016/j.electacta.2006.09.060
Park SJ , Kim MH 2000 Effect of acidic anode treatment on carbonfibers for increasing fiber-matrix adhesion and its relationship to interlaminar shear strength of composites J Mater Sci 35 1901 -    DOI : 10.1023/A:1004754100310
Li M , Wen X , Liu J , Tang T 2014 Synergetic effect of epoxy resin and maleic anhydride grafted polypropylene on improving mechanical properties of polypropylene/short carbon fiber composites Compos Pt A-Appl Sci Manuf 67 212 -    DOI : 10.1016/j.compositesa.2014.09.001
Park SJ , Park BJ , Ryu SK 1999 Electrochemical treatment on activated carbon fibers for increasing the amount and rate of Cr (VI) adsorption Carbon 37 1223 -    DOI : 10.1016/S0008-6223(98)00318-2
Rhee YH , Ahn DJ , Ko MJ , Jin HY , Jin JH , Min NK 2014 Enhanced electrocatalytic activity of plasma functionalized multi-walled carbon nanotube-entrapped poly (3,4-ethylendioxythiophene):poly (styrene sulfonate) photocathode Electrochim Acta 146 68 -    DOI : 10.1016/j.electacta.2014.09.021
Park SJ , Park BJ 1999 Electrochemically Modified PAN Carbon Fibers and Interfacial Adhesion in Epoxy-resin Composites J Mater SciLett 18 47 -    DOI : 10.1023/A:1006673309571
Heibati B , Rodriguez-Couto S , Amrane A , Rafatullah M , Hawari A , Al-Ghouti MA 2013 Uptake of Reactive Black 5 by pumice and walnut activated carbon: Chemistry and adsorption mechanisms J Ind Eng Chem 20 2939 -    DOI : 10.1016/j.jiec.2013.10.063
Park SJ , Cho KS , Ryu SK 2003 Filler-elastomer interactions: influence of oxygen plasma treatment on surface and mechanical propertiesof carbon black/rubber composites Carbon 41 1437 -    DOI : 10.1016/S0008-6223(03)00088-5
Shim JW , Park SJ , Ryu SK 2001 Effect of modification with HNO3 and NaOH on metal adsorption by pitch-based activated carbon fibers Carbon 39 1635 -    DOI : 10.1016/S0008-6223(00)00290-6
Park SJ , Jang YS 2001 Interfacial Characteristics and Fracture Toughness of Electrolytically Ni-Plated Carbon Fiber-Reinforced Phenolic Resin Matrix Composites J Colloid Interface Sci 237 91 -    DOI : 10.1006/jcis.2001.7441
Kim S , Park SJ 2006 Effects of chemical treatment of carbon supports on electrochemical behaviors for platinum catalysts of fuel cells J Power Sources 159 42 -    DOI : 10.1016/j.jpowsour.2006.04.041
Park SJ , Kim BJ 2005 Roles of acidic functional groups of carbon fiber surfaces in enhancing interfacial adhesion behavior Mater Sci Eng A 408 269 -    DOI : 10.1016/j.msea.2005.08.129
Park SJ , Seo MK , Lee YS 2003 Surface characteristics of fluorinemodified PAN-based carbon fibers Carbon 41 723 -    DOI : 10.1016/S0008-6223(02)00384-6
Kim BJ , Lee YS , Park SJ 2008 A study on the hydrogen storage capacity of Ni-plated porous carbon nanofibers Int J Hydrog Energy 33    DOI : 10.1016/j.ijhydene.2008.05.077
Meng LY , Park SJ 2010 Effect of heat treatment on CO2 adsorption of KOH-activated graphite nanofibers 352 498 -    DOI : 10.1016/j.jcis.2010.08.048
Jung MJ , Kim JW , Im JS , Park SJ , Lee YS 2009 Nitrogen and hydrogen adsorption of activated carbon fibers modified by fluorination J Ind Eng Chem 15 410 -    DOI : 10.1016/j.jiec.2008.11.001
Kim BJ , Lee YS , Park SJ 2008 Novel porous carbons synthesized from polymeric precursors for hydrogen storage Int J Hydrog Energy 33 2254 -    DOI : 10.1016/j.ijhydene.2008.02.019
Im JS , Park SJ , Lee YS 2007 Preparation and characteristics of electrospun activated carbon materials having meso- and macropores J Colloid Interface Sci 314 32 -    DOI : 10.1016/j.jcis.2007.05.033
Park SJ , Jang YS , Shim JW , Ryu SK 2003 Studies on pore structures and surface functional groups of pitch-based activated carbon fibers J Colloid Interface Sci 260 259 -    DOI : 10.1016/S0021-9797(02)00081-4
Im JS , Kwon O , Kim YH , Park SJ , Lee YS 2008 The effect of embedded vanadium catalyst on activated electrospun CFs for hydrogen storage Microporous Mesoporous Mat 115 514 -    DOI : 10.1016/j.micromeso.2008.02.027
Im JS , Park SJ , Kim TJ , Kim YH , Lee YS 2008 The study of controllingpore size on electrospun carbon nanofibers for hydrogen adsorption J Colloid Interface Sci 318 42 -    DOI : 10.1016/j.jcis.2007.10.024
Park SJ , Kim KD 1999 Adsorption Behaviors of CO2 and NH3 on Chemically Surface-Treated Activated Carbons J Colloid Interface Sci 212 186 -    DOI : 10.1016/j.jcis.2998.6058
Shen Z , Ma J , Mei Z , Zhang J 2010 Metal chlorides loaded on activated carbon to capture elemental mercury J Environ Sci 22 1814 -    DOI : 10.1016/S1001-0742(09)60324-7
Park SJ , Kim BJ 2005 Ammonia removal of activated carbon fibers produced by oxyfluorination J Colloid Interface Sci 291 597 -    DOI : 10.1016/j.jcis.2005.05.012
Lee SJ , Seo YC , Jurng J , Lee TG 2004 Removal of gas-phase elemental mercury by iodine-and chlorine-impregnated activated carbons Atmos Environ 38 4887 -    DOI : 10.1016/j.atmosenv.2004.05.043
Mei Z , Shen Z , Zhao Q , Wang W , Zhang Y 2008 Removal and recovery of gas-phase element mercury by metal oxide-loaded activated carbon J Hazard Mater 152 721 -    DOI : 10.1016/j.jhazmat.2007.07.038
Park SJ , Jin SY 2005 Effect of ozone treatment on ammonia removal of activated carbons J Colloid Interface Sci 286 417 -    DOI : 10.1016/j.jcis.2005.01.043
De M , Azargohar R , Dalai AK 2013 Shewchuk SR. Mercury removal bybio-char based modified activated carbons Fuel 103 570 -    DOI : 10.1016/j.fuel.2012.08.011
Park SJ , Kim BJ 2004 Influence of oxygen plasma treatment on hydrogenchloride removal of activated carbon fibers J Colloid Interface Sci 275 590 -    DOI : 10.1016/j.jcis.2004.03.011
Karatza D , Prisciandaro M , Lancia A , Musmarra D 2011 Silver impregnated carbon for adsorption and desorption of elemental mercuryvapors J Environ Sci 23 1578 -    DOI : 10.1016/S1001-0742(10)60528-1
Park SJ , Jang YS 2002 Pore Structure and Surface Properties of Chemically Modified Activated Carbons for Adsorption Mechanism and Rate of Cr(VI) J Colloid Interface Sci 249 458 -    DOI : 10.1006/jcis.2002.8269
Hsi HC , Chen CT 2012 Influences of acidic/oxidizing gases on elemental mercury adsorption equilibrium and kinetics of sulfurimpregnated activated carbon Fuel 98 229 -    DOI : 10.1016/j.fuel.2012.04.011
Park SJ , Jang YS 2003 Preparation and characterization of activated carbon fibers supported with silver metal for antibacterial behavior J Colloid Interface Sci 261 238 -    DOI : 10.1016/S0021-9797(03)00083-3
Saha A , Abram DN , Kuhl KP , Paradis J , Crawford JL , Sasmaz E , Chang R , Jaramillo TF , Wilcox J 2013 An X-ray Photoelectron SpectroscopyStudy of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performanceof Pellet versus Fiber Sorbents Environ Sci Technol 47 13695 -    DOI : 10.1021/es403280z
Saman N , Johari K , Mat H 2014 Adsorption Characteristics of Sulfur-Functionalized Silica Microspheres with Respect to the Removal of Hg(II) from Aqueous Solutions Ind Eng Chem Res 53 1225 -    DOI : 10.1021/ie402824r
Reddy KSK , Shoaibi AlA , Srinivasakannan C 2013 Gas-phase mercuryremoval through sulfur impregnated porous carbon J Ind Eng Chem 20 2969 -    DOI : 10.1016/j.jiec.2013.10.067
Ie IR , Chen WC , Yuan CS , Hung CH , Lin YC 2012 Enhancing the adsorptionof vapor-phase mercury chloride with an innovative compositesulfur-impregnated activated carbon J Hazard Mater 217-218 43 -    DOI : 10.1016/j.jhazmat.2012.02.035
Kim BJ , Bae KM , Park SJ 2012 Microporous and Mesoporous Materials Microporous Mesoporous Mat 163 270 -    DOI : 10.1016/j.micromeso.2012.05.038
Bae KM , Kim BJ , Rhee KY , Park SJ 2014 Roles of Metal/Activated Carbon Hybridization on Elemental Mercury Adsorption J Nanosci Nanotechnol 14 5811 -    DOI : 10.1166/jnn.2014.8459
Song N , Teng Y , Wang J , Liu Z , Orndorff W , Pan WP 2014 Effect of modified fly ash with hydrogen bromide on the adsorption efficiencyof elemental mercury J Therm Anal Calorim 116 1189 -    DOI : 10.1007/s10973-014-3701-y
Sasmaz E , Kirchofer A , Jew AD , Saha A , Abram D 2012 Mercury chemistry on brominated activated carbon Fuel 99 188 -    DOI : 10.1016/j.fuel.2012.04.036
Yao Y , Velpari V , Economy J 2014 Design of sulfur treated activatedcarbon fibers for gas phase elemental mercury removal Fuel 116 560 -    DOI : 10.1016/j.fuel.2013.08.063
Tian L , Li C , Li Q , Zeng G , Gao Z , Li S , Fan X 2009 Removal of elemental mercury by activated carbon impregnated with CeO2 Fuel 88 1687 -    DOI : 10.1016/j.fuel.2009.01.022
Tao S , Li C , Fan X , Zeng G , Lu P , Zhang X 2012 Activated coke impregnatedwith cerium chloride used for elemental mercury removalfrom simulated flue gas Chem Eng J 210 547 -    DOI : 10.1016/j.cej.2012.09.028
Kim BJ , Bae KM , Park SJ 2011 A Study of the Optimum Pore Structure for Mercury Vapor Adsorption Bull Korean Chem Soc 32 1507 -    DOI : 10.5012/bkcs.2011.32.5.1507
Xu W , Wang H , Zhu T , Kuang J , Jing P 2013 Mercury removal from coal combustion flue gas by modified fly ash J Environ Sci 25 393 -    DOI : 10.1016/S1001-0742(12)60065-5
Kolker A , Engle MA , Peucker-Ehrenbrink B 2013 Atmospheric mercuryand fine particulate matter in coastal New England: Implications for mercury and trace element sources in the northeastern United States Atmos Environ 79 760 -    DOI : 10.1016/j.atmosenv.2013.07.031
Jaworek A , Czech T , Sobczyk AT , Krupa A 2013 Properties of biomassvs. coal fly ashes deposited in electrostatic precipitator J Electrost 71 165 -    DOI : 10.1016/j.elstat.2013.01.009
Gao Y , Zhang Z , Wu J , Duan L , Umar A , Sun L , Guo Z , Wang Q 2013 A Critical Review on the Heterogeneous Catalytic Oxidation of Elemental Mercury in Flue Gases Environ Sci Technol 47 10813 -    DOI : 10.1021/es402495h
Scala F , Clack HL 2008 Mercury emissions from coal combustion: Modeling and comparison of Hg capture in a fabric filter versus an electrostatic precipitator J Hazard Mater 152 616 -    DOI : 10.1016/j.jhazmat.2007.07.024
Wang Y , Liu Y , Mo J , Wu Z 2012 Effects of Mg2+ on the bivalent mercuryreduction behaviors in simulated wet FGD absorbents J Hazard Mater 237-238 256 -    DOI : 10.1016/j.jhazmat.2012.08.036
Sun M , Hou J , Cheng G , Baig SA , Tan L , Xu X 2014 The relationshipbetween speciation and release ability of mercury in flue gas desulfurization(FGD) gypsum Fuel 125 66 -    DOI : 10.1016/j.fuel.2014.02.012
Wu S , Wang S , Gao J , Wu Y , Chen G , Zhu Y 2011 Interactions betweenmercury and dry FGD ash in simulated post combustion conditions J Hazard Mater 188 391 -    DOI : 10.1016/j.jhazmat.2011.01.119
Kong F , Qiu J , Liu H , Zhao R , Ai Z 2011 Catalytic oxidation of gasphaseelemental mercury by nano-Fe2O3 J Environ Sci 23 699 -    DOI : 10.1016/S1001-0742(10)60438-X
Liu Y , Wang Y , Wang H , Wu Z 2011 Catalytic oxidation of gas-phase mercury over Co/TiO2 catalysts prepared by sol-gel method Catal Commun 12 1291 -    DOI : 10.1016/j.catcom.2011.04.017
Xu Y , Zhong Q , Liu X 2014 Elemental mercury oxidation and adsorptionon magnesite powder modified by Mn at low temperature J Hazard Mater 283 252 -    DOI : 10.1016/j.jhazmat.2014.09.034
Chen W , Ma Y , Yan N , Qu Z , Yang S , Xie J , Guo Y The co-benefitof elemental mercury oxidation and slip ammonia abatement with SCR-Plus catalysts Fuel 133 263 -    DOI : 10.1016/j.fuel.2014.04.086
Yang J , Yang Q , Sun J , Liu Q , Zhao D , Gao W 2015 Effects of mercury oxidation on V2O5-WO3/TiO2 catalyst properties in NH3-SCR process Catal Commun 59 78 -    DOI : 10.1016/j.catcom.2014.09.049
Rallo M , Heidel B , Brechtel K 2012 Effect of SCR operation variableson mercury speciation Chem Eng J 198-199 87 -    DOI : 10.1016/j.cej.2012.05.080