CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Hailong Li,Qin Yang,Wenqi Qu,Yong Feng,Lijian Leng,Jiexia Zhao,Fanyue Meng,Zequn Yang,Jianping Yang
The critical challenge to achieve cost-effective elemental mercury (Hg 0 ) capture from coal combustion flue gas by using mineral sulfides lies in developing a facile method to realize their fixed-bed application, which hence exhausts the adsorption capacity of mineral sulfides and optimize their economic-sustainability. In this work, a feasible and facile synthesis procedure based on a one-step cetyltrimethylammonium bromide (CTAB) assisted precipitation procedure was proposed to overcome this challenge. During this process, the CTAB played a crucial role to effectively confine the particle size of copper sulfide (CuS) in nanoscale and stably anchor it over the macroporous polyurethane foam (PUF) skeleton. The macropore-enriched CuS/PUF as synthesized was merited for its high throughput morphology, nanoscale particle size of CuS, homogeneous distribution of active components, and multiform surface sulfur ligands, which is promising to be used in a fixed-bed scenario to achieve efficient Hg 0 sequestration. These benefits co-derived an excellent Hg 0 sorbent with extremely high uptake capacity and adsorption rate (265.6 mg g −1 and 2.16 mg g −1 min −1 ), exceeding those of other mineral sulfides and traditional activated carbons as reported in previous studies by folds, even by magnitudes. With such an outstanding Hg 0 sequestration performance and a macroporous structure, it can be reasonably concluded that the CuS/PUF will be a potential sorbent to be adopted in a fixed-bed scenario, which optimizes the cost-effectiveness of mineral sulfide based sorbents and extend their application flexibility for the Hg 0 adsorption from coal combustion flue gas.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yahui Wang,Qihuang Huo,Huijun Chen,Yu Feng,Jiancheng Wang,Sheng Wang,Liping Chang,Weiren Bao
To develop the high value utilization of high organic sulfur coal instead of combustion as well as save the cost of mercury pollution control, we attempted to transmute the inherent sulfur of high organic sulfur coal, in the case of LF coal (which is from Linfen city, China), to active sulfur species for mercury capture by doping metal oxides, and CuO performed best among various metal oxides. The sorbent (or activated sample) prepared from LF coal with doping CuO is labelled LF+Cu-A, around which a series of experiments were conducted. Firstly, the effects of operational conditions, including GHSV (gas hourly space velocity), temperature and flue components, on the mercury capture performance of LF+Cu-A were thoroughly investigated, and results showed that LF+Cu-A had an excellent mercury capture performance. The average mercury capture efficiency is 97.8 % during a two-hour test under N 2 +O 2 +H 2 O+SO 2 +NO atmosphere with GHSV of 240000 h −1 and temperature of 120 °C. Secondly, the experimental data were fitted by four kinetic models, and it is found that the mercury adsorption process under low temperatures (60, 90, 120 °C) and high temperature (150 °C) are in the best agreement with the pseudo-first-order model and the intra-particle diffusion model respectively. Last, the mercury capture mechanisms of LF+Cu-A were revealed by Hg-TPD (Hg-temperature programed desorption) experiment, Raman analysis and XPS (X-ray photoelectron spectrometer) spectra, and it is indicated that the multiple sulfur species and Cu 2+ play roles in the mercury capture process, during which elemental mercury are oxidized to HgS and fixed on the surface of LF+Cu-A.
研究领域:
环境科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Zequn Yang,Hailong Li,Chen Liao,Jiexia Zhao,Shihao Feng,Pu Li,Xi Liu,Jianping Yang,Kaimin Shih
Rattle-type Fe3O4@CuS synthesized using a two-step method was applied for elemental mercury (Hg0) adsorption in coal combustion flue gas for the first time. The Fe3O4 with strong magnetization was an ideal candidate as a core to make the sorbent recyclable, while the stabilized ultrathin CuS shell assured that the Fe3O4@CuS had a higher Brunauer–Emmett–Teller (BET) surface area with more exposed active sites and stronger magnetization. The optimal operating temperature of 75 °C allowed for the injection of the sorbent between the wet desulfurization (WFGD) and wet electrostatic precipitator (WESP), which removed the detrimental influence of nitrogen oxides. Simulated flue gas (SFG) in this section showed a slight inhibitive effect on Hg0 adsorption over the Fe3O4@CuS, mainly due to the presence of water vapor (H2O). The inhibition of H2O was proven to be the result of an active site prevention effect instead of the widely recognized competitive adsorption effect. The adsorption capacity and rate of the Fe3O4@CuS for Hg0 capture reached 80.73 mg g–1 and 13.22 μg (g min)−1, which were the highest values among the magnetic sorbents currently reported for Hg0 removal from coal combustion flue gas. These properties allowed the sorbent to maintain a 100% Hg0 capture efficiency for more than 20 h with only a 50 mg dosage when no regeneration step was applied. Meanwhile, the contacting time between the sorbent and Hg0 was generally less than 5 s in a typical sorbent injection process. Polysulfides dominated the capturing process and primarily contributed to the extremely high adsorption capacity/rate. A multistep reaction mechanism was proposed to explain the Hg0 adsorption over Fe3O4@CuS. At the first stage, polysulfide participated in Hg0 adsorption as the most active component and was consumed rapidly. After that, S–S dimers, sulfides, and even copper-terminated sites functioned as the adsorption centers. The as-formed mercury–copper (Hg–Cu) amalgam was transformed into mercury sulfide (HgS), a process that was dependent on the extent of the saturation of sulfide sites. With these advantages, Fe3O4@CuS is a promising, cost-effective, highly recyclable, and efficient alternative to the traditional activated carbon for capturing Hg0 in coal combustion flue gases.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
LANGMUIR
·
2018
·
IF 3.789
Zequn Yang,Hailong Li,Shihao Feng,Pu Li,Chen Liao,Xi Liu,Jiexia Zhao,Jianping Yang,Po-Heng Lee,Kaimin Shih
Nanostructured copper sulfide synthesized with the assistance of surfactant with nanoscale particle size and high Brunauer–Emmett–Teller surface area was for the first time applied for the capture of elemental mercury (Hg0) from coal combustion flue gas. The optimal operation temperature of nano-CuS for Hg0 adsorption is 75 °C, which indicates that injection of the sorbent between the wet flue gas desulfurization and the wet electrostatic precipitator systems is feasible. This assures that the sorbent is free of the adverse influence of nitrogen oxides. Oxygen (O2) and sulfur dioxide exerted a slight influence on Hg0 adsorption over the nano-CuS. Water vapor was shown to moderately suppress Hg0 capture efficiency via competitive adsorption. The simulated adsorption capacities of nano-CuS for Hg0 under pure nitrogen (N2), N2 + 4% O2, and simulated flue gas reached 122.40, 112.06, and 89.43 mgHg0/g nano-CuS, respectively. Compared to those of traditional commercial activated carbons and metal sulfides, the simulated adsorption capacities of Hg0 over the nano-CuS are at least an order of magnitude higher. Moreover, with only 5 mg loaded in a fixed-bed reactor, the Hg0 adsorption rate reached 11.93–13.56 μg/g min over nano-CuS. This extremely speedy rate makes nano-CuS promising for a future sorbent injection technique. The anisotropic growth of nano-CuS was confirmed by X-ray diffraction analysis and provided a fundamental aspect for nano-CuS surface reconstruction and polysulfide formation. Further X-ray photoelectron spectroscopy and Hg0 temperature-programmed desorption tests showed that the active polysulfide, S–S dimers, and copper-terminated sites contributed primarily to the extremely high Hg0 adsorption capacity and rate. With these advantages, nano-CuS appears to be a highly promising alternative to traditional sorbents for Hg0 capture from coal combustion flue gas.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
Advanced Science
·
2019
·Vol. 6
·期 20
·1901410
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IF 15.804
Zequn Yang,Hailong Li,Junwei Yang,Qin Yang,Jiexia Zhao,Jianping Yang,Wenqi Qu,Yong Feng,Kaimin Shih
The key challenge of vapor-phase elemental mercury (Hg 0 ) sequestration is the rational design of a sorbent with abundantly available ligands that exhibit excellent affinity toward Hg 0 to simultaneously achieve a high uptake capacity and rapid capture rate. In this work, it is demonstrated how the correct combination of functional ligands and structural properties can form an ideal remediator for permanent Hg 0 immobilization. The adsorption capacity of an amorphous molybdenum triselenide (MoSe 3 ) nanosheet greater than 1000 mg g −1 is the highest recorded value compared to previously reported sorbents tested in a fixed-bed reactor. Meanwhile, the uptake rate of 240 µg g −1 min −1 is also the highest recorded rate value. Mercury selenide as formed exhibits extremely low leachability when environmentally exposed. This impressive performance is primarily attributed to the appropriate layer space between the nanosheets that permeated Hg 0 and the existence of diselenide (Se 2 2− ) ligands that exhibit excellent affinity toward Hg 0 . Thus, this work not only provides a promising trap for permanent Hg 0 sequestration from industrial and domestic sources with minimum hazard but also provides a detailed illustration of using structural advantages to obtain an ideal sorbent as well as guidance for the further development of Hg 0 decontamination techniques.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
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2020
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IF 3.421
Dongjing Liu,Zhen Zhang,Fei Luo,Jiang Wu
Graphite-phase carbon nitrides (g-C3N4), composed of only C, N, and some impurity H, have been synthesized by direct thermal polymerization of urea in air and employed to capture elemental mercury (Hg0) from simulated flue gas. The performance and kinetic behavior of g-C3N4 toward Hg0 adsorption are investigated. Its optimal polymerization temperature and ramping rate are 550 °C and 5 K/min, respectively. It shows extraordinary affinity with elemental mercury associated with an Hg0 removal efficiency >77% at 40–240 °C under a nitrogen atmosphere, which is probably attributed to its unique electronic structure property and fluffy tremella-like morphology with ample exposed adsorption sites. The Hg0 may be captured on the sp2-bonded carbon atoms in g-C3N4 by producing carbon–mercury (C–Hg) covalent bonds via Lewis acid–base interaction. The presence of O2 slightly reduces the mercury capture efficiency, while the Hg0 removal efficiency greatly decreases by nearly a half in the presence of H2O, NO, and SO2, which is plausibly owing to the competitive adsorption or deletion of active sites on the g-C3N4 surface. The process of Hg0 adsorption on g-C3N4 is controlled by both intraparticle diffusion and chemisorption processes.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2018
·
IF 3.024
Dongjing Liu,Cheng Lu,Jiang Wu
Graphitic carbon nitride (g-C3N4) as a 2D layered carbon material with exceptional electronic, thermal, and catalytic property has attracted increasing research attention. A porous g-C3N4 nanosheet (PCNN) has been synthesized via a facile two-step thermal etching oxidation approach and applied in low-temperature elemental mercury (Hg0) removal. PCNN exhibits good reactivity toward Hg0 adsorption at temperatures of 40–200 °C. CuO impregnation can prominently enhance the Hg0 capture performance of PCNN on account of the intimate interaction of CuO and PCNN. Temperature has a positive effect on Hg0 capture ability of PCNN and CuO/PCNN. Hg0 is mainly oxidized by the chemisorbed oxygen species that are generated from the O–C–N of g-C3N4 and the lattice oxygen of CuO. CuO modification can efficiently activate g-C3N4 with significantly improved Hg0 capture ability presumably owing to the Mott–Schottky effect at the interface of CuO and g-C3N4.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）