Effect of porous structure and surface functionality on the mercury capacity of a fly ash carbon and its activated sample

Maroto‐Valer, M. Mercedes; Zhang, Yinzhi; Granite, Evan J.; Tang, Zhong Hua; Pennline, Henry W.

doi:10.1016/j.fuel.2004.07.005

Cited by 104 publications

(67 citation statements)

References 16 publications

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“…16 A positive correlation between UBC content of fly ash, sometimes noted as loss on ignition (LOI), and mercury retention has been demonstrated by different researchers. 2,13,[17][18][19][20] The capacity of fly ash for HgCl 2 and Hg°are similar, 9 but the adsorption rate is higher for HgCl 2 . 21 Results from Baltrus et al 22 showed that UBC concentrates from different fly ash samples have properties similar to most carbon blacks.…”

Section: Introductionmentioning

confidence: 94%

“…Such behavior suggests that surface area itself is not as critical to mercury capture as the surface functional groups destroyed during the activation processes, such as oxygen containing functionalities, fluorine, chlorine, and sulfate salts. 18,24 Fly ash-mediated oxidation is an important mechanism for mercury oxidation. Some of the fly ash components promote oxidation of Hg°, whereas others do not.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Fly Ash Composition on Mercury Speciation in Simulated Flue Gas

Bhardwaj

Chen

Vidic

2009

Journal of the Air & Waste Management Association

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The impact of different fly ash samples on mercury speciation in simulated flue gas at 140°C was evaluated in this study. Experiments were conducted in a fixed bed reactor to determine the impact of fly ash morphological characteristics and chemical composition on mercury uptake and oxidation. No homogeneous mercury oxidation was observed at 140°C. Mercury uptake tests with different fly ash samples revealed that loss on ignition (LOI), surface area, and particle size all had positive effects on mercury oxidation and adsorption (i.e., as the above parameters increased, mercury adsorption and oxidation also increased). Experiments with pure inorganic components showed that alumina (Al 2 O 3 ), silica (SiO 2 ), calcium oxide (CaO), magnesium oxide (MgO), and titania (TiO 2 ) do not promote mercury oxidation or adsorption. Ferric oxide (Fe 2 O 3 ) and unburned carbon, on the other hand, showed significant mercury oxidation and capture.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Impact of Fly Ash Composition on Mercury Speciation in Simulated Flue Gas

Bhardwaj

Chen

Vidic

2009

Journal of the Air & Waste Management Association

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“…Adsorption in liquid phase is a complex phenomenon because both, solute and solvent, compete for the solid surface. Briefly, the adsorption of a solute depends on its molecular size and chemical properties, on the textural properties of the adsorbent and on its surface chemistry [22][23] . Most of the mercury in solution exists as complexed species, which can be either positive, negative or neutral, depending on the composition and pH of the solution.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of mercury (II) from liquid solutions using modified activated carbons

et al. 2010

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Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury abatement. Activated carbons are universal adsorbents which have been found to be a very effective alternative for mercury removal from water. The effectiveness with which a contaminant is adsorbed by the solid surface depends, among other factors, on the charge of the chemical species in which the contaminant is in solution and on the net charge of the adsorbent surface which depend on the pH of the adsorption system. In this work, activated carbon from carbonized eucalyptus wood was used as adsorbent. Two sulphurization treatments by impregnation with sulphuric acid and with carbon disulphide, have been carried out to improve the adsorption capacity for mercury entrapment. Batch adsorption tests at different temperatures and pH of the solution were carried out. The influence of the textural properties, surface chemistry and operation conditions on the adsorption capacity, is discussed.

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“…It is also mercury adsorbent, but the adsorption capacity of inorganic fl y ash fractions is low for mercury. The numerous attempts made to determine the relation between carbon or volatile matter content and the effi ciency of gaseous mercury sorption on the ash, in most cases have indicated considerable infl uence of the specifi c surface area, the content of mineral particulate fractions in the ash, and the fl ue gas temperature (Baochun et al 2000, Gibb et al 2000, Tan et al 2004, Maroto-Valer et al 2005, Rubel et al 2005, Rubel et al 2006, Wang et al 2007, Hower et al 2010. Mercury in the form of HgO and Hg 2+ may be subject to partial sorption on the fl y ash which contains considerable quantities of unburned carbon, and such phenomenon was observed in hot fl ue gas, above the temperature of 500°C (Baochun et al 2000, Wang et al 2007).…”

Section: Mercury Adsorption On the Fl Y Ash Surfacementioning

confidence: 99%

Transformations of mercury in processes of solid fuel combustion – review

Czaplicka¹,

Pyta²

2017

Archives of Environmental Protection

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Abstract:The paper presents current reports on kinetics and mechanisms of reactions with mercury which take place in the exhaust gases, discharged from the processes of combustion of solid fuels (coals). The three main stages were considered. The fi rst one, when thermal decomposition of Hg components takes place together with formation of elemental mercury (Hg 0 ). The second one with homogeneous oxidation of Hg 0 to Hg 2+ by other active components of exhaust gases (e.g. HCl). The third one with heterogeneous reactions of gaseous mercury (the both -elemental and oxidised Hg) and solid particles of fl y ash, leading to generation of particulate-bound mercury (Hg p ). Infl uence of exhaust components and their concentrations, temperature and retention time on the effi ciency of mercury oxidation was determined. The issues concerning physical (gas-solid) and chemical speciation of mercury (fractionation Hg 0 -Hg 2+ ) as well as factors which have infl uence on the mercury speciation in exhaust gases are discussed in detail.

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Effect of porous structure and surface functionality on the mercury capacity of a fly ash carbon and its activated sample

Cited by 104 publications

References 16 publications

Impact of Fly Ash Composition on Mercury Speciation in Simulated Flue Gas

Impact of Fly Ash Composition on Mercury Speciation in Simulated Flue Gas

Adsorption of mercury (II) from liquid solutions using modified activated carbons

Transformations of mercury in processes of solid fuel combustion – review

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