Mechanism identification of temperature influence on mercury adsorption capacity of different halides modified bio-chars

Li, Guoliang; Ding, Dian; Shen, Bo

doi:10.1016/j.cej.2017.01.030

Cited by 66 publications

(23 citation statements)

References 36 publications

(49 reference statements)

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“…Among the numerous removal techniques, heterogeneous adsorption is currently the most effective method and has been extensively studied . When optimizing the performance of adsorbents, researchers first focus on the adsorption capacity, stability, and selectivity of the material. − However, the presence of other atmospheres in the flue gas, such as sulfur dioxide (SO 2 ), and large fluctuations in temperature are still a challenge for the adsorption of Hg 0 . − …”

Section: Introductionmentioning

confidence: 99%

Strengthen the Affinity of Element Mercury on the Carbon-Based Material by Adjusting the Coordination Environment of Single-Site Manganese

Huang

et al. 2021

Environ. Sci. Technol.

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Mercury, as a highly poisonous pollutant, poses a severe threat to the global population. However, the removal of Hg 0 can only be carried out at below 100 °C due to the weak binding of the adsorbent. Herein, a series of carbon-based materials with different coordination environments and atomic dispersion of single-site manganese were prepared, and their elemental mercury removal performance was systematically investigated. It was demonstrated that the coordination environment around manganese determines its electronic structure and size, thus affecting its affinity with mercury. The obtained best adsorbents atomically dispersed Mn with atom size near 0.2 nm, achieves high Hg 0 removal efficiency and over 13 mg/g Hg 0 adsorption capacity at 200 °C. And the SO 2 resistance performance of single atoms (∼0.2 nm) is much better than clusters (∼1− 2 nm) because of its high selectivity, that the effect of SO 2 is only 3%. Density functional theory (DFT) reveals that Mn with four-nitrogen atoms (Mn−N 4 -CO) is more active than other number nitrogen coordination materials. Moreover, the presence of carboxyl groups around manganese also promotes affinity for Hg 0 . This work might shed new light on the enhancement of Hg 0 affinity in carbon-based materials and the rational design of the coordination structure of the tunable Hg 0 activities.

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Section: Introductionmentioning

confidence: 99%

Strengthen the Affinity of Element Mercury on the Carbon-Based Material by Adjusting the Coordination Environment of Single-Site Manganese

Huang

et al. 2021

Environ. Sci. Technol.

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“…Using separate equipment to control Hg 0 and AsH 3 could result in larger capital investments for equipment, higher operation costs, and other possible problems related to process complexity. In previous studies, metal oxide catalysts and halide modified sorbents have been reported to have high activity for both Hg 0 and AsH 3 removal separately, ,, but these studies rarely combined the metal oxides and halide. Furthermore, studies have been carried out using gases with an oxygen content of 8–10% in N 2 , , but examples of removing contaminants from a reducing atmosphere (approximately 80% CO) under low temperature and micro-oxygen conditions (1%) have rarely been reported.…”

Section: Introductionmentioning

confidence: 99%

“…17 Sorbents modified using halides (such as Cl, Br, I) have also been widely used to control mercury emissions. 20,21 For example, Li et al 22 have reported considerable enhancement in the removal of mercury over halide modified biochars. Also, Shen et al 23 studied the removal of Hg 0 by an NH 4 Cl impregnated sorbent.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Removal of Elemental Mercury and Arsine from a Reducing Atmosphere Using Chloride and Cerium Modified Activated Carbon

Zhang

Ning

Wang

et al. 2019

Ind. Eng. Chem. Res.

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With the goal of simultaneous removal of elemental mercury and arsine from simulated yellow phosphorus off-gas, a series of Cl–Ce modified activated carbon samples were prepared via an impregnation method and investigated. The Cl3–Ce10/AC exhibited the best performance at 150 °C, with an Hg0 removal efficiency of 92.2%, and the reaction time of AsH3 removal efficiency greater than 90% was 15.5 h. The presence of Hg0 had little impact on AsH3 removal, but conversely AsH3 significantly reduced Hg0 removal efficiency. The effects of individual flue gas components on the simultaneous removal of Hg0 and AsH3 were also studied. O2 clearly promoted the simultaneous removal of Hg0 and AsH3 and CO had almost no influence, while H2S and water vapor inhibited the removal process. The physicochemical properties of the samples were characterized using BET, FESEM-EDS, XRD, and XPS. By combining experimental results with physical and chemical characterization, a mechanism for simultaneous removal of Hg0 and AsH3 was proposed. It was found that chemical adsorption and catalytic oxidation occurred on the surface of the samples, due to the presence of chlorine covalent bonds and cerium oxides, and that the presence of cerium makes it easier for mercury to combine with chlorine. The main products in the used samples were found to be HgCl2, HgO, and As2O3.

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“…It is inferred that, during the mechanical milling process, the unburned carbon on the fly ash surface reacts with NaBr crystal, which promotes the formation of CBr covalent group and is consistent with the result of no characteristic peak of NaBr observed in XRD patterns. It has shown that the CBr covalent group is the main chemisorption site of Hg 0 , which determines the mercury adsorption capacity of the modified adsorbent …”

Section: Results and Discussionmentioning

confidence: 99%

Effect of Mechanical–Chemical Modification Process on Mercury Removal of Bromine Modified Fly Ash

Geng

Duan

et al. 2020

Energy Fuels

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As a new modification method, mechanochemistry features the remarkable advantages of simple operation process, low energy consumption, easy chemical modification, and suitability for industrialization. In this work, the coal-fired byproduct fly ash was modified by a mechanical–chemical method through omnidirectional planetary ball mill. The effect of the mechanical–chemical modification process parameters on the performance of mercury removal and physicochemical properties of the fly ash and the relationship between the mercury removal efficiency and the physicochemical properties were studied. The experimental results showed that, under the condition of single mechanical ball milling, the mercury removal efficiency of fly ash (FA) was slightly higher than that of raw FA. After being modified by NaBr, the mercury removal efficiency of FA increased considerably with the increase of ball milling time and speed and decreased with the increase of the size of the grinding ball. However, it was no longer significantly improved with further increasing the ball milling time and speed owing to the limited unburned carbon content in FA. The best modification process parameters were determined from the ball milling time of 1 h, the ball milling speed of 400 rpm, and the ball size of 5 mm. The characterization results showed that there was no big difference in physical properties of FA between various mechanical–chemical modification processes. However, the content of carbonyl and carboxyl/ester groups and C–Br covalent groups on modified FA demonstrated a key role in promoting mercury removal performance. The contents of carbonyl and carboxyl/ester groups and C–Br covalent groups were positively proportional to the mercury removal rate, and they were consumed during mercury adsorption. The results confirmed that the improvement of mercury removal efficiency of modified FA was dominated mainly by the surface chemical properties. Compared with the carbonyl and carboxyl/ester groups, the C–Br covalent group was the major chemisorption site of Hg0.

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Mechanism identification of temperature influence on mercury adsorption capacity of different halides modified bio-chars

Cited by 66 publications

References 36 publications

Strengthen the Affinity of Element Mercury on the Carbon-Based Material by Adjusting the Coordination Environment of Single-Site Manganese

Strengthen the Affinity of Element Mercury on the Carbon-Based Material by Adjusting the Coordination Environment of Single-Site Manganese

Simultaneous Removal of Elemental Mercury and Arsine from a Reducing Atmosphere Using Chloride and Cerium Modified Activated Carbon

Effect of Mechanical–Chemical Modification Process on Mercury Removal of Bromine Modified Fly Ash

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