Elemental mercury oxidation over manganese oxide octahedral molecular sieve catalyst at low flue gas temperature

Liu, Xi; Jiang, Shaojian; Li, Hailong; Yang, Jianping; Yang, Zhaoguang; Zhao, Jiexia; Peng, Haoyi; Shih, Kaimin

doi:10.1016/j.cej.2018.08.225

Cited by 68 publications

(35 citation statements)

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“…Each sample displayed three partially overlapped reduction peaks (marked as α, β, and γ), corresponding to a three-step reduction process. For OMS-2, peak α at 320 • C was attributed to the consumption of readily reducible superficial species, which were principally related to the surface labile oxygen species and surface manganese oxide clusters (2MnO 2 [25]. After Cu doping, all of peaks α, β, and γ moved remarkably towards lower temperatures (as compared with those of the OMS-2 support), signifying a strong metal-support interaction between the Cu species and the OMS-2.…”

Section: Reducibilitymentioning

confidence: 99%

Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

Chen

et al. 2021

Catalysts

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Different Cu contents (x wt%) were supported on the cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) (xCu/OMS-2; x = 1, 5, 15, and 20) via a pre-incorporation method. Physicochemical properties of the OMS-2 and xCu/OMS-2 samples were characterized by means of the XRD, FT-IR, SEM, TG/DTG, ICP-OES, XPS, O2-TPD, H2-TPR, and in situ DRIFTS techniques, and their catalytic activities were measured for the oxidation of CO, ethyl acetate, and toluene. The results show that the Cu species were homogeneously dispersed in the tunnel and framework structure of OMS-2. Among all of the samples, 15Cu/OMS-2 sample exhibited the best activities with the T50% of 65, 165, and 240 °C as well as the T90% of 85, 215, and 290 °C for CO, ethyl acetate and toluene oxidation, respectively, which was due to the existence of the Cu species and Mn3+/Mn4+ redox couples, rich oxygen vacancies, good oxygen mobility, low-temperature reducibility, and strong interaction between the Cu species and the OMS-2 support. The reaction mechanisms were also deduced by analyzing the in situ DRIFTS spectra of the 15Cu/OMS-2 sample. The excellent oxygen mobility associated with the electron transfer between Cu species and Mn3+/Mn4+ redox couples might be conducive to the continuous replenishment of active oxygen species and the constantly generated reactant intermediates, thereby increasing the reactant reaction rate.

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Section: Reducibilitymentioning

confidence: 99%

Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

Chen

et al. 2021

Catalysts

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“…Molecular sieve catalysts for oxidation reaction are mainly transition metal ion exchange zeolites and specific types of zeolite zeolites, and these zeolite catalysts only show high temperature activity. Liu et al [98] first used solvent-free synthesis of cryptomelane OMS-2 to oxidize waste material in coal-fired flue gas, which provided a new idea for oxidative denitrification by molecular sieve. Geng et al [99] prepared zinc oxide nanoparticle molecular sieves by melt infiltration method to remove exhaust gas at room temperature.…”

Section: Catalytic Oxidation Of Molecular Sievementioning

confidence: 99%

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Liu

et al. 2019

Catalysts

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Nitrogen oxides (NO x ) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NO x , it is urgent to control NO x . According to the different mechanisms of NO x removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NO x . At the same time, the current research status and existing problems of different NO x removal technologies were revealed and the future development prospects were forecasted.Catalysts 2019, 9, 771 2 of 39 adsorption, oxidation, reduction, and plasma methods. In view of these attentive findings, adsorption method uses recyclable solid adsorbent material to adsorb NO x from flue gas through microporous structure, remarkably, environmentally friendly, no secondary pollution, and energy-saving and -efficient features make it stand out [18][19][20]. The oxidation process is a method that oxidizes NO into NO 2 or N 2 O 3 with high solubility under the action of an oxidant that is then absorbed by water or alkali solution. The process is simple and cost-saving, and is widely used in the wet flue gas denitrification process with relatively low cost and high removal efficiency of NO x ; except that the oxidized NO and SO 2 can be removed simultaneously to produce high value-added products [21][22][23]. The reduction method has the characteristics of high efficiency, cleanliness, and mildness; NO x removal can be realized at low temperature at present [24][25][26]. The plasma method is used to modify the surface of the catalyst, the dispersion of active species can be improved by plasma treatment, and the stability and low temperature activity of catalyst can be improved [27,28].Seldom, if ever, does a comprehensive article to introduce the current situation and treatment methods of removing NO x . In this paper, we tried to renovate, classify, and summarize the significant perspectives and most relevant findings reported in recent research articles and earlier reviews generalizing the mechanism analysis and research progress of NO x removal by adsorption, oxidation, reduction, and plasma methods, which can provide means for promoting the technological progress of pollution prevention, maintaining healthy development of factories continuously, studying the methods of removing NO x deeply, and mastering different technologies of removing NO x , as well as providing guidance for controlling the emission of NO x from motor vehicles such as diesel, gasoline, and so on. In order to improve the environmental quality and save the ecological environment, this paper further provides a convenient, low-cost, efficient, and economic guidance line.

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“…prepared OMS‐2 by adding potassium into MnO x without changing the crystal structure [19] . The specific surface area of OMS‐2 reaches 162.87 m 2 /g, in contrast, the value of MnO 2 is only 8.25 m 2 /g [15] . Especially, manganese in OMS‐2 mostly exists as Mn 3+ and Mn 4+ , corresponding to the excellent catalytic oxidation ability [16,17] .…”

Section: Introductionmentioning

confidence: 99%

“…Mn‐based catalysts usually possess excellent performance for Hg 0 oxidation at 100–250 °C due to its multiple valence and oxygen vacancies [11–14] . However, the poor structure of MnO x would suppress the process of Hg 0 oxidation [15] . Loading MnO x on the porous supporters or adding other metal into MnO x structure were has been to improve the structure performance of MnO x [16,17] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

One‐Pot Hydrothermal Synthesis for a Manganese Oxide Molecular Sieve for Application in Mercury Removal in Chloride‐Free Flue Gas

et al. 2022

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OMS‐2 (manganese oxide octahedral molecular sieve) were prepared by one pot hydrothermal method under different temperatures in this work, and their performances of oxidizing elemental mercury (Hg0) in the flue gas derived from coal combustion were evaluated. Moreover, the effects of the reaction temperature and flue gas component on Hg0 oxidation ability of these catalysts were also investigated. It is found that OMS‐2 catalysts have an excellent mercury oxidizing ability under 100–200 °C, and 94 % Hg0 oxidation efficiency could be achieved by catalyst prepared under 120 °C (OMS‐2‐H120) in the chlorine free flue gas. The process of elemental mercury oxidation over OMS‐2‐H120 by O2 is found to follow Mars‐Maessen mechanism based on the XPS and FTIR analysis of the fresh and spent catalysts. NO is the precursors of the active species such as NO−, NO2, which is benefit to improve Hg0 oxidation ability of OMS‐2‐H120. SO2 have a negative effect on Hg0 oxidation over OMS‐2‐H120 while water vapor exhibits nearly no influence.

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Elemental mercury oxidation over manganese oxide octahedral molecular sieve catalyst at low flue gas temperature

Cited by 68 publications

References 50 publications

Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

One‐Pot Hydrothermal Synthesis for a Manganese Oxide Molecular Sieve for Application in Mercury Removal in Chloride‐Free Flue Gas

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