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Zhou Z, Cao T, Liu X, Xu J, Deng L, Li C, Liu J, Xu M. Mechanistic investigation of elemental mercury adsorption over silver-modified vanadium silicate: A DFT study. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124108. [PMID: 33032090 DOI: 10.1016/j.jhazmat.2020.124108] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Ag-modified vanadium silicate (EVS-Ag) has been regarded as a superior sorbent for elemental mercury (Hg0) capture from coal-fired flue gas. However, the atomic-level reaction mechanism which determines Hg0 adsorption capacity of EVS-Ag sorbent remains elusive. Reaction mechanism and active sites of Hg0 adsorption over EVS-Ag sorbent were studied using density functional theory (DFT) calculations systematically. DFT calculation results indicate that silver exchange shows little effects on the geometric structure of EVS-10 sorbent. Hg0 adsorption on EVS-10 and EVS-Ag surfaces is controlled by the physisorption and chemisorption mechanisms, respectively. Ag2 cluster is determined to be the most active site of Hg0 adsorption over Ag-modified EVS sorbent. The adsorption energy of Hg0 on Ag2 cluster is -51.93 kJ/mol. The orbital hybridization and electron sharing between Ag and Hg atoms are responsible for the strong interaction between EVS-Ag surface and Hg0. HgO prefers to adsorb on Ag2 cluster of EVS-Ag sorbent, and yields an energy release of 306.21 kJ/mol. HgO desorption from EVS-Ag sorbent surface needs a higher external energy, and occurs at the relatively higher temperatures. O2 molecule promotes Hg0 adsorption over EVS-Ag sorbent. HgO species can be easily formed during Hg0 adsorption over EVS-Ag sorbent in the presence of O2.
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Affiliation(s)
- Zijian Zhou
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
| | - Tiantian Cao
- SINOPEC Research Institute of Petroleum Processing, Beijing 100083, China
| | - Xiaowei Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China.
| | - Jie Xu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
| | - Lidan Deng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
| | - Chengpu Li
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
| | - Jing Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
| | - Minghou Xu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
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Antuña-Nieto C, Rodríguez E, Lopez-Anton MA, García R, Martínez-Tarazona MR. Noble metal-based sorbents: A way to avoid new waste after mercury removal. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123168. [PMID: 32563907 DOI: 10.1016/j.jhazmat.2020.123168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
The development of technologies to control mercury emissions is now a legal requirement imposed by recent international agreements. The use of regenerable sorbents is consistent with this requirement as it allows mercury to be captured from industrial gases without generating new mercury-containing toxic waste. Because regenerable sorbents based on noble metals are often questioned due to the heavy investment they entail, this study assesses the viability of their use in terms of efficiency and cost. Its primary aim is to develop new regenerable sorbents based on an activated carbon support impregnated with Ag in order to compare their cost and behavior in a CO2 enriched gas stream with that of similar materials containing Au. Mercury retention efficiencies of 100 % can be achieved over several adsorption-desorption cycles depending on the type of noble metal used, particle size and impurities in the gas atmosphere. The results suggest that the Hg-Ag amalgamation process differs from the Hg-Au one, in that they show different kinetics of adsorption and temperatures of desorption. The Ag and Au regenerable sorbents developed in this study would be competitive given the environmental and health benefits they offer compared to the single-use activated carbons employed until now at industrial scale.
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Affiliation(s)
- Cristina Antuña-Nieto
- Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, Francisco Pintado Fe, 26, 33011, Oviedo, Spain
| | - Elena Rodríguez
- Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, Francisco Pintado Fe, 26, 33011, Oviedo, Spain
| | - Maria Antonia Lopez-Anton
- Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, Francisco Pintado Fe, 26, 33011, Oviedo, Spain.
| | - Roberto García
- Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, Francisco Pintado Fe, 26, 33011, Oviedo, Spain
| | - M Rosa Martínez-Tarazona
- Instituto de Ciencia y Tecnología del Carbono, INCAR-CSIC, Francisco Pintado Fe, 26, 33011, Oviedo, Spain
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3
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Zhou Z, Cao T, Liu X, Xu S, Xu Z, Xu M. Vanadium silicate (EVS)-supported silver nanoparticles: A novel catalytic sorbent for elemental mercury removal from flue gas. JOURNAL OF HAZARDOUS MATERIALS 2019; 375:1-8. [PMID: 31030075 DOI: 10.1016/j.jhazmat.2019.04.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/09/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
Vanadium silicate (EVS) is a vanadium-substituted form of titanosilicate that has a high potential for use as a sorbent for mercury removal. In the present study, EVS with supported silver nanoparticles (EVS-Ag100) as the catalytic sorbent was synthesized for elemental mercury (Hg°) capture. The physical and chemical properties of the sorbents were investigated. The raw EVS exhibited a poor Hg° capture capacity (7.7 μg g-1), because most of the vanadium species in the structure of EVS were V4+. The loading of the silver could significantly enhance the Hg° capture capacity (63.4 μg g-1). EVS-Ag100 exhibited a superior Hg° capture performance at temperatures of approximately 150 °C. Silver nanoparticles that formed on the EVS were the active sites. In addition, the vanadium species of EVS-Ag100 exhibited higher Hg° oxidation activity than those in the framework of raw EVS. The XPS results revealed the activation of the vanadium species by the silver nanoparticles. After the capture of Hg° in the presence of O2, more V5+ was observed on the surface of EVS-Ag100. Exposure of EVS-Ag100 to a continuous simulated flue gas at 150 °C with a gas hourly space velocity of 220,000 h-1 led to Hg° removal efficiency of >96% in a 1 h test.
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Affiliation(s)
- Zijian Zhou
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Tiantian Cao
- SINOPEC Research Institute of Petroleum Processing, Beijing 100083, China; Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Xiaowei Liu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Shengming Xu
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Zhenghe Xu
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China; Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Minghou Xu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
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Tang Q, Ji W, Guo W, Shen Z, Fan M. First-Principle Study on Heterofullerenes: Effective and Multifunctional in Hg Removal. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b01382] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Qingli Tang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, People’s Republic of China
| | - Wenchao Ji
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, People’s Republic of China
- College of Resource and Environment, Anhui Science and Technology University, Donghua Road, Fengyang, Anhui 233100, People’s Republic of China
| | - Weimin Guo
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, People’s Republic of China
| | - Zhemin Shen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, People’s Republic of China
| | - Maohong Fan
- School of Energy Resources and Departments of Chemical and Petroleum Engineering, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82071, United States
- School of Civil and Environmental Engineering, Georgia Institute of Technology, North Avenue, Atlanta, Georgia 30332, United States
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5
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Mettela G, Kouser S, Sow C, Pantelides ST, Kulkarni GU. Nobler than the Noblest: Noncubic Gold Microcrystallites. Angew Chem Int Ed Engl 2018; 57:9018-9022. [PMID: 29847008 DOI: 10.1002/anie.201804541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Indexed: 11/06/2022]
Abstract
Conventional gold comprising the cubic lattice is universally known for its stability. However, well known to chemists and metallurgists, this nobility is challenged by reagents such as aqua regia, which dissolve gold to form a salt solution. Among metals, mercury blends with gold to form amalgam, otherwise transition metals such as copper tend to interact with gold surfaces in electrochemical media. Herein, we report a combined experimental and theoretical investigation of the stability of Au microcrystallites bearing unconventional crystal lattices that exhibit enhanced stability towards Hg and aqua regia and practically no interaction with Cu during electroless plating. The unconventional gold is undoubtedly nobler.
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Affiliation(s)
- Gangaiah Mettela
- Thematic Unit of Excellence on Nanochemistry, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560 064, India
| | - Summayya Kouser
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA.,Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Chaitali Sow
- Thematic Unit of Excellence on Nanochemistry, and Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560 064, India
| | - Sokrates T Pantelides
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA.,Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Giridhar U Kulkarni
- Centre for Nano and Soft Matter Sciences, Jalahalli, Bangalore, 560013, India
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6
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Mettela G, Kouser S, Sow C, Pantelides ST, Kulkarni GU. Nobler than the Noblest: Noncubic Gold Microcrystallites. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gangaiah Mettela
- Thematic Unit of Excellence on Nanochemistry, and Chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) Jakkur P.O. Bangalore 560 064 India
| | - Summayya Kouser
- Department of Physics and Astronomy Vanderbilt University Nashville TN USA
- Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge TN USA
| | - Chaitali Sow
- Thematic Unit of Excellence on Nanochemistry, and Chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) Jakkur P.O. Bangalore 560 064 India
| | - Sokrates T. Pantelides
- Department of Physics and Astronomy Vanderbilt University Nashville TN USA
- Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge TN USA
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7
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Pershina V. Reactivity of Superheavy Elements Cn, Nh, and Fl and Their Lighter Homologues Hg, Tl, and Pb, Respectively, with a Gold Surface from Periodic DFT Calculations. Inorg Chem 2018; 57:3948-3955. [DOI: 10.1021/acs.inorgchem.8b00101] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Valeria Pershina
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany
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8
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Jung JE, Liguori S, Jew AD, Brown GE, Wilcox J. Theoretical and experimental investigations of mercury adsorption on hematite surfaces. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2018; 68:39-53. [PMID: 28829689 DOI: 10.1080/10962247.2017.1362364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED One of the biggest environmental concerns caused by coal-fired power plants is the emission of mercury (Hg), which is toxic metal. To control the emission of Hg from coal-derived flue gas, it is important to understand the behavior and speciation of Hg as well as the interaction between Hg and solid materials in the flue gas stream. In this study, atomic-scale theoretical investigations using density functional theory (DFT) were carried out in conjunction with laboratory-scale experimental studies to investigate the adsorption behavior of Hg on hematite (α-Fe2O3). According to the DFT simulation, the adsorption energy calculation proposes that Hg physisorbs to the α-Fe2O3(0001) surface with an adsorption energy of -0.278 eV, and the subsequent Bader charge analysis confirms that Hg is slightly oxidized. In addition, Cl introduced to the Hg-adsorbed surface strengthens the Hg stability on the α-Fe2O3(0001) surface, as evidenced by a shortened Hg-surface equilibrium distance. The projected density of states (PDOS) analysis also suggests that Cl enhances the chemical bonding between the surface and the adsorbate, thereby increasing the adsorption strength. In summary, α-Fe2O3 has the ability to adsorb and oxidize Hg, and this reactivity is enhanced in the presence of Cl. For the laboratory-scale experiments, three types of α-Fe2O3 nanoparticles were prepared using the precursors Fe(NO3)3, Fe(ClO4)3, and FeCl3, respectively. The particle shapes varied from diamond to irregular stepped and subrounded, and particle size ranged from 20 to 500 nm depending on the precursor used. The nanoparticles had the highest surface area (84.5 m2/g) due to their highly stepped surface morphology. Packed-bed reactor Hg exposure experiments resulted in this nanoparticles adsorbing more than 300 μg Hg/g. The Hg LIII-edge extended X-ray absorption fine structure spectroscopy also indicated that HgCl2 physisorbed onto the α-Fe2O3 nanoparticles. IMPLICATIONS Atomic-scale theoretical simulations proposes that Hg physisorbs to the α-Fe2O3(0001) surface with an adsorption energy of -0.278 eV, and the subsequent Bader charge analysis confirms that Hg is slightly oxidized. In addition, Cl introduced to the Hg-adsorbed surface strengthens the Hg stability on the α-Fe2O3(0001) surface, as evidenced by a shortened Hg-surface equilibrium distance. The PDOS analysis also suggests that Cl enhances the chemical bonding between the surface and the adsorbate, thereby increasing the adsorption strength. Following laboratory-scale experiment of Hg sorption also shows that HgCl2 physisorbs onto α-Fe2O3 nanoparticles which have highly stepped structure.
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Affiliation(s)
- Ji-Eun Jung
- a Department of Energy Resources Engineering, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , CA , USA
| | - Simona Liguori
- a Department of Energy Resources Engineering, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , CA , USA
| | - Adam D Jew
- b Department of Geological Sciences, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , CA , USA
| | - Gordon E Brown
- b Department of Geological Sciences, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , CA , USA
- c Department of Photon Science and Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , CA , USA
| | - Jennifer Wilcox
- a Department of Energy Resources Engineering, School of Earth, Energy, and Environmental Sciences , Stanford University , Stanford , CA , USA
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Han L, Li Q, Chen S, Xie W, Bao W, Chang L, Wang J. A Magnetically Recoverable Fe 3O 4-NH 2-Pd Sorbent for Capture of Mercury from Coal Derived Fuel Gas. Sci Rep 2017; 7:7448. [PMID: 28785101 PMCID: PMC5547139 DOI: 10.1038/s41598-017-07802-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/29/2017] [Indexed: 11/09/2022] Open
Abstract
A sort of magnetical material named Fe3O4-NH2-Pd was prepared by loading varying amounts of immobilizing Pd on the surface of the magnetic Fe3O4-NH2 microspheres. This magnetical material was used firstly for capturing Hg° from coal derived fuel gas based on its recoverability. The experimental results showed that the loading Pd on the amine-functionalized magnetite nanoparticles can greatly improve the efficiency of removing Hg° at a high temperature range between 200 and 300 °C. The magnetic Fe3O4-NH2-Pd sorbent with 5% Pd loaded exhibited significantly high activity and stability in capturing Hg°, affording over 93% capture efficiency at 200 °C for more than 8 hrs. Compared to the Fe3O4-NH2 sorbent that converted the Hg° as HgS, this Fe3O4-NH2-Pd sorbent can remove the Hg° by forming Pd-Hg amalgam and HgS. In addition, the experimental tests indicated that the as-synthesized Fe3O4-NH2-Pd sorbent still showed stable magnetic properties after two regeneration cycles in removing Hg°, which provided the opportunity for preparing a recyclable sorbent which can be easily separated and recovered for Hg° removal.
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Affiliation(s)
- Lina Han
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Qinglian Li
- State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Ministry of Science and Technology and Shanxi Province, Taiyuan University of Technology, Taiyuan, China
| | - Shuai Chen
- Analytical Instrumentation Center, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, China.
| | - Wei Xie
- Chemical Engineering University of Newcastle, Callaghan, NSW 2308, Australia
| | - Weiren Bao
- State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Ministry of Science and Technology and Shanxi Province, Taiyuan University of Technology, Taiyuan, China
| | - Liping Chang
- State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Ministry of Science and Technology and Shanxi Province, Taiyuan University of Technology, Taiyuan, China
| | - Jiancheng Wang
- State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Ministry of Science and Technology and Shanxi Province, Taiyuan University of Technology, Taiyuan, China.
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Kalita B. Tuning the Adsorption of Elemental Mercury by Small Gas-Phase Palladium Clusters: First-Principles Study. J Phys Chem A 2016; 120:7714-7731. [DOI: 10.1021/acs.jpca.6b06910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bulumoni Kalita
- Department of Physics, Dibrugarh University, Dibrugarh, Assam 786004, India
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Yu JG, Yue BY, Wu XW, Liu Q, Jiao FP, Jiang XY, Chen XQ. Removal of mercury by adsorption: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:5056-5076. [PMID: 26620868 DOI: 10.1007/s11356-015-5880-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/24/2015] [Indexed: 06/05/2023]
Abstract
Due to natural and production activities, mercury contamination has become one of the major environmental problems over the world. Mercury contamination is a serious threat to human health. Among the existing technologies available for mercury pollution control, the adsorption process can get excellent separation effects and has been further studied. This review is attempted to cover a wide range of adsorbents that were developed for the removal of mercury from the year 2011. Various adsorbents, including the latest adsorbents, are presented along with highlighting and discussing the key advancements on their preparation, modification technologies, and strategies. By comparing their adsorption capacities, it is evident from the literature survey that some adsorbents have shown excellent potential for the removal of mercury. However, there is still a need to develop novel, efficient adsorbents with low cost, high stability, and easy production and manufacture for practical utility.
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Affiliation(s)
- Jin-Gang Yu
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China.
| | - Bao-Yu Yue
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Xiong-Wei Wu
- College of Science, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Qi Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Fei-Peng Jiao
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Xin-Yu Jiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Xiao-Qing Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
- Collaborative Innovation Center of Resource-Conserving and Environment-Friendly Society and Ecological Civilization, Changsha, Hunan, 410083, China
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12
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Dou R, Yang Y, Zhang P, Zhong D, Fuchs H, Wang Y, Chi L. Building chessboard-like supramolecular structures on Au(111) surfaces. NANOTECHNOLOGY 2015; 26:385601. [PMID: 26314756 DOI: 10.1088/0957-4484/26/38/385601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate an anthracene derivative, 3(5)-(9-anthryl) pyrazole (ANP), self-assembled on the Au(111) surface by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. A chessboard-like network structure composed of ANP molecules is found, covering the whole Au(111) substrate. Our STM results and DFT calculations reveal that the formation of chessboard-like networks originates from a basic unit cell, a tetramer structure, which is formed by four ANP molecules connected through C-H…N hydrogen bonds. The hydrogen bonds inside each tetramer and the molecule-substrate interaction are fundamentally important in providing a driving force for formation of the supramolecular networks.
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Affiliation(s)
- Ruifen Dou
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
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13
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Gómez-Giménez C, Ballestero D, Juan R, Rubio B, Izquierdo M. Mercury capture by a regenerable sorbent under oxycoal combustion conditions: Effect of SO 2 and O 2 on capture efficiency. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.09.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Zhao Y, Hao R, Guo Q. A novel pre-oxidation method for elemental mercury removal utilizing a complex vaporized absorbent. JOURNAL OF HAZARDOUS MATERIALS 2014; 280:118-126. [PMID: 25146096 DOI: 10.1016/j.jhazmat.2014.07.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/04/2014] [Accepted: 07/30/2014] [Indexed: 06/03/2023]
Abstract
A novel semi-dry integrative method for elemental mercury (Hg(0)) removal has been proposed in this paper, in which Hg(0) was initially pre-oxidized by a vaporized liquid-phase complex absorbent (LCA) composed of a Fenton reagent, peracetic acid (CH3COOOH) and sodium chloride (NaCl), after which Hg(2+) was absorbed by the resultant Ca(OH)2. The experimental results indicated that CH3COOOH and NaCl were the best additives for Hg(0) oxidation. Among the influencing factors, the pH of the LCA and the adding rate of the LCA significantly affected the Hg(0) removal. The coexisting gases, SO2 and NO, were characterized as either increasing or inhibiting in the removal process, depending on their concentrations. Under optimal reaction conditions, the efficiency for the single removal of Hg(0) was 91%. Under identical conditions, the efficiencies of the simultaneous removal of SO2, NO and Hg(0) were 100%, 79.5% and 80.4%, respectively. Finally, the reaction mechanism for the simultaneous removal of SO2, NO and Hg(0) was proposed based on the characteristics of the removal products as determined by X-ray diffraction (XRD), atomic fluorescence spectrometry (AFS), the analysis of the electrode potentials, and through data from related research references.
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Affiliation(s)
- Yi Zhao
- School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, P.R. China.
| | - Runlong Hao
- School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, P.R. China
| | - Qing Guo
- School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, P.R. China
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15
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Yin CY, Ng MF, Saunders M, Goh BM, Senanayake G, Sherwood A, Hampton M. New Insights into the adsorption of aurocyanide ion on activated carbon surface: electron microscopy analysis and computational studies using fullerene-like models. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:7703-7709. [PMID: 24967902 DOI: 10.1021/la501191h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Despite decades of concerted experimental studies dedicated to providing fundamental insights into the adsorption of aurocyanide ion, Au(CN)2(-), on activated carbon (AC) surface, such a mechanism is still poorly understood and remains a contentious issue. This adsorption process is an essential unit operation for extracting gold from ores using carbon-in-pulp (CIP) technology. We hereby attempt to shed more light on the subject by employing a range of transmission electron microscopy (TEM) associated techniques. Gold-based clusters on the AC surface are observed by Z-contrast scanning TEM imaging and energy-filtered TEM element mapping and are supported by X-ray microanalysis. Density functional theory (DFT) calculations are applied to investigate this adsorption process for the first time. Fullerene-like models incorporating convex, concave, or planar structure which mimic the eclectic porous structures on the AC surface are adopted. Pentagonal, hexagonal, and heptagonal arrangements of carbon rings are duly considered in the DFT study. By determining the favored adsorption sites in water environment, a general adsorption trend of Au(CN)2(-) adsorbed on AC surface is revealed whereby concave > convex ≈ planar. The results suggest a tendency for Au(CN)2(-) ion to adsorb on the carbon sheet defects or edges rather than on the basal plane. In addition, we show that the adsorption energy of Au(CN)2(-) is approximately 5 times higher than that of OH(-) in the alkaline environment (in negative ion form), compared to only about 2 times in acidic environment (in protonated form), indicating the Au extraction process is much favored in basic condition. The overall simulation results resolve certain ambiguities about the adsorption process for earlier studies. Our findings afford crucial information which could assist in enhancing our fundamental understanding of the CIP adsorption process.
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Affiliation(s)
- Chun-Yang Yin
- School of Science and Engineering, Teesside University , Borough Road, Middlesbrough TS1 3BA, United Kingdom
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Lien CW, Chen YC, Chang HT, Huang CC. Logical regulation of the enzyme-like activity of gold nanoparticles by using heavy metal ions. NANOSCALE 2013; 5:8227-8234. [PMID: 23860719 DOI: 10.1039/c3nr01836a] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this study we employed self-deposition and competitive or synergistic interactions between metal ions and gold nanoparticles (Au NPs) to develop OR, AND, INHIBIT, and XOR logic gates through regulation of the enzyme-like activity of Au NPs. In the presence of various metal ions (Ag(+), Bi(3+), Pb(2+), Pt(4+), and Hg(2+)), we found that Au NPs (13 nm) exhibited peroxidase-, oxidase-, or catalase-like activity. After Ag(+), Bi(3+), or Pb(2+) ions had been deposited on the Au NPs, the particles displayed strong peroxidase-like activity; on the other hand, they exhibited strong oxidase- and catalase-like activities after reactions with Ag(+)/Hg(2+) and Hg(2+)/Bi(3+) ions, respectively. The catalytic activities of these Au NPs arose mainly from the various oxidation states of the surface metal atoms/ions. Taking advantage of this behavior, we constructed multiplex logic operations-OR, AND, INHIBIT, and XOR logic gates-through regulation of the enzyme-like activity after the introduction of metal ions into the Au NP solution. When we deposited Hg(2+) and/or Bi(3+) ions onto the Au NPs, the catalase-like activities of the Au NPs were strongly enhanced (>100-fold). Therefore, we could construct an OR logic gate by using Hg(2+)/Bi(3+) as inputs and the catalase-like activity of the Au NPs as the output. Likewise, we constructed an AND logic gate by using Pt(4+) and Hg(2+) as inputs and the oxidase-like activity of the Au NPs as the output; the co-deposition of Pt and Hg atoms/ions on the Au NPs was responsible for this oxidase-like activity. Competition between Pb(2+) and Hg(2+) ions for the Au NPs allowed us to develop an INHIBIT logic gate-using Pb(2+) and Hg(2+) as inputs and the peroxidase-like activity of the Au NPs as the output. Finally, regulation of the peroxidase-like activity of the Au NPs through the two inputs Ag(+) and Bi(3+) enabled us to construct an XOR logic gate.
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Affiliation(s)
- Chia-Wen Lien
- Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
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Lim DH, Wilcox J. Heterogeneous mercury oxidation on au(111) from first principles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8515-8522. [PMID: 23805868 DOI: 10.1021/es400876e] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Density functional theory (DFT) studies of mercury oxidation on Au(111) are conducted to determine the potential Hg oxidation mechanisms taking place on catalytic gold surfaces by using the Perdew and Wang approximation (PW91) described by a generalized gradient approximation (GGA). The Hg oxidation was examined via a Langmuir-Hinshelwood mechanism where each Hg(0) and Cl2 (or HCl) species is separately adsorbed on the gold surface and the bimolecular reaction occurs through the formation of bound HgCl and HgCl2. For this, the Climbing Image-Nudged Elastic Band (CI-NEB) method has been employed to calculate the activation energies of HgCl and HgCl2 formation pathways. In the three-step Hg oxidation mechanism (Hg → HgCl → HgCl2), the second Cl attachment step is endothermic which is the reaction rate-limiting step, while the first Cl attachment step is exothermic. This observation implies that Hg oxidation prefers a pathway in which HgCl and HgCl2 are formed, rather than a pathway directly oxidizing Hg to HgCl2. In the presence of H atoms due to HCl dissociation on the Au surface, the H atoms lower the activation energy for Hg oxidation by consuming the electron charge of Au atoms, thereby weakening the strength of interaction between Cl and the Au surface and lowering an energy required to detach Cl from the Au surface. This mechanism is in the absence of site competition on the Au surface. In addition, details of the electronic properties of these systems are discussed.
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Affiliation(s)
- Dong-Hee Lim
- Fuel Cell Research Center, Korea Institute of Science and Technology (KIST) , Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
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