Study on arsenic/lead adsorption characteristics by mineral oxides in coal-fired flue gas
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摘要: 选取典型的矿物质氧化物为吸附剂，在两段式固定床反应器中研究了模拟烟气气氛下吸附剂吸附As2O3、PbO的特性，吸附反应的原子态密度、吸附位、吸附能等通过密度泛函理论（DFT）计算获得。结果表明，CaO的砷吸附容量最大，900 ℃吸附砷容量为5.25 mg/g；其次是Fe2O3、MgO、Al2O3，吸附的砷以As3+和As5+的砷酸盐形式存在，高岭土和飞灰具有较大的PbO吸附容量，最大吸附容量分别为6.69和2.75 mg/g；其次是SiO2和Al2O3，并且50%SiO2/50%Al2O3混合吸附剂的铅吸附容量高于单一氧化物，吸附剂表面O原子是As2O3的吸附活性位点，吸附剂暴露的不饱和Si和Al原子是PbO的吸附活性位点，此外温度、烟气气氛对吸附容量和吸附产物有显著影响。Abstract: The As2O3 or PbO adsorption characteristics using typical mineral oxides as the sorbents were studied in a two-stage fixed-bed reactor under a simulated flue gas, and the density of atomic states, adsorption sites, and adsorption energy for the adsorption reaction were calculated by density functional theory (DFT). The results demonstrate that CaO has a large As2O3 adsorption capacity, with an arsenic adsorption capacity of 5.25 mg/g at 900 ℃, followed by Fe2O3, MgO, and Al2O3; and the adsorbed arsenic exists in the form of As3+ and As5+ arsenates. Kaolin and fly ash have large PbO adsorption capacities, with the maximum lead adsorption capacities of 6.69 and 2.75 mg/g, respectively, followed by SiO2 and Al2O3, and the adsorption capacity for lead with the 50%SiO2/50%Al2O3 mixture is higher than that with their single oxide. The oxygen atoms on the surface of the sorbents are the active sites for As2O3 and the unsaturated Si and Al atoms exposed on the surface of the sorbents are the active sites for PbO. In addition, the adsorption temperature and flue gas atmosphere have significant effects on the adsorption capacity and adsorption products of the sorbents.
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Key words:
- heavy metal /
- coal combustion /
- adsorption mechanism /
- oxide sorbents
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图 3 300-900℃下矿物质氧化物的砷吸附容量
Figure 3 Arsenic adsorption capacity of mineral oxides at 300-900 ℃
图 5 吸附剂吸附As2O3反应前后的结构示意图
Figure 5 Structure diagram of sorbents before and after adsorbing As2O3
1: before adsorption; 2: after adsorption; a: CaO; b: Na2O; c: MgO; d: Fe2O3; e: Al2O3; f: SiO2
图 9 700-1200 ℃下Si/Al基吸附剂的铅吸附容量
Figure 9 Lead adsorption capacity of Si/Al-based sorbents at 700-1200 ℃
图 10 900 ℃下高温煅烧Si/Al基吸附剂的铅吸附容量
Figure 10 Lead adsorption capacity of high temperature calcined Si/Al-based sorbents at 900 ℃
图 11 SiO2(001)和Al2O3(100)吸附PbO的稳定构型
Figure 11 Stable structure of PbO adsorption on SiO2(001) and Al2O3(100) surfaces
图 12 Al2O3(100)面掺杂Si后吸附PbO的稳定构型
Figure 12 Stable structure of PbO adsorption on the Al2O3(100) surface after doping with Si
图 13 Al2O3(100)面吸附PbO的态密度
Figure 13 Density of states of PbO adsorbed on the Al2O3(100) surface
a: three-coordinated doped Si; b: two-coordinated doped Si; 1: O in PbO; 2: doped Si; 3: Al; 4: Pb in PbO; 5: O on the surface
图 14 SiO2在1000 ℃吸附PbO样品Pb 4f XPS谱图
Figure 14 Pb 4f XPS spectra of SiO2 with adsorbed PbO at 1000 ℃
表 1 氧化物吸附剂的结构特性
Table 1 Structure properties of the oxide sorbents investigated
Sample Structure properties surface area A/(m2·g-1) pore diameter d/nm pore volumev/(×10-2 cm3·g-1) CaO 5.27 23.34 3.08 MgO 4.71 19.78 0.21 Na2O 3.62 10.18 0.74 Fe2O3 11.79 18.01 3.06 Al2O3 1.65 7.91 0.12 SiO2 1.87 8.93 0.11 
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表 2 吸附剂吸附砷的吸附能
Table 2 Adsorption energy of sorbents for adsorbing arsenic
Surface Adsorption energy E/(kJ·mol-1) CaO(001) -216.63 MgO(100) -170.21 Na2O(110) -336.98 Fe2O3(001) -358.00 Al2O3(100) -203.23 SiO2(001) -156.40
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表 3 不同温度下SiO2(001)吸附PbO的ΔG
Table 3 ΔG of SiO2(001) adsorbing PbO
Temperature T/K ΔG /(kJ·mol-1) 300 -173.36 800 -133.47 1300 11.02 1800 32.42
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[1] CHEN J, LIU G, KANG Y, WU B, SUN R, ZHOU C, WU D. Atmospheric emissions of F, As, Se, Hg, and Sb from coal-fired power and heat generation in China[J]. Chemosphere, 2013, 90(6): 1925-1932. http://www.sciencedirect.com/science/article/pii/S0045653512012714 [2] Environmental Protection Agency. Locating and estimating air emissions from sources of arsenic and arsenic compounds: Final Report[R]. United States: EPA, 1998. [3] 刘慧敏, 王春波, 郭永成, 张月, 黄星智, 王家伟.高砷褐煤与低砷烟煤混燃砷的挥发特性及模型[J].化工学报, 2016, 67(10), 4477-4484. http://d.wanfangdata.com.cn/Periodical/hgxb201610055LIU Hui-min, WANG Chun-bo, GUO Yong-cheng, ZHANG Yue, HUANG Xing-zhi, WANG Jia-wei. Experimental and modeling study on arsenic volatilization during co-combustion of high arsenic lignite and low arsenic bituminous coal[J]. CIESC J, 2016, 67(10): 4477-4484. http://d.wanfangdata.com.cn/Periodical/hgxb201610055 [4] WANG C, ZHANG Y, SHI Y, LIU H, ZOU C, WU H, KANG X. Research on collaborative control of Hg, As, Pb and Cr by electrostatic-fabric-integrated precipitator and wet flue gas desulphurization in coal-fired power plants[J]. Fuel, 2017, 210: 527-534. https://www.sciencedirect.com/science/article/pii/S0016236117310694 [5] TIAN H, WANG Y, XUE Z, QU Y, CHAI F, HAO J. Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China[J]. Sci Total Environ, 2011, 409(16): 3078-3081. http://www.sciencedirect.com/science/article/pii/S004896971100427X [6] 方婷, 煤矿区中铅的环境地球化学研究[D].合肥: 中国科学技术大学, 2015.FANG Ting. Environmental geochemistry of lead in coal mining area[D]. Hefei: University of Science and Technology of China, 2015. [7] CHEN L, ZHOU S, WU S, WANG C, HE D. Concentration, fluxes, risks, and sources of heavy metals in atmospheric deposition in the Lihe River watershed, Taihu region, eastern China[J]. Environ Pollut, 2019, 255: 113301. https://www.sciencedirect.com/science/article/pii/S0269749119334165 [8] WANG J, ZHANG Y, LIU Z, NORRIS P, ROMERO C E, XU H, PAN W. Effect of coordinated air pollution control devices in coal-fired power plants on arsenic emissions[J]. Energy Fuels, 2017, 31(7): 7309-7316. doi: 10.1021/acs.energyfuels.7b00711 [9] OLIVEIRA M L, IZQUIERDO M, QUEROL X, LIEBERMAN R N, SAIKIA B K, SILVA L F. Nanoparticles from construction wastes: A problem to health and the environment[J]. J Clean Prod, 2019, 219: 236-243. http://www.sciencedirect.com/science/article/pii/S0959652619304858 [10] LINAK WP, WENDT J O. Toxic metal emissions from incineration: Mechanisms and control[J]. Prog Energy Combust Sci, 1993, 19: 145-185. http://www.sciencedirect.com/science/article/pii/0360128593900146 [11] WENDT J O, LEE S J. High-temperature sorbents for Hg, Cd, Pb, and other trace metals: Mechanisms and applications[J]. Fuel 2010, 89: 894-903. http://www.ingentaconnect.com/content/el/00162361/2010/00000089/00000004/art00016 [12] WANG J, ZHANG Y, WANG T, XU H, PAN W. Effect of modified fly ash injection on As, Se, and Pb emissions in coal-fired power plant[J]. Chem Eng J, 2020, 380: 122561. http://www.sciencedirect.com/science/article/pii/S1385894719319643 [13] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会.环境空气质量标准[Z]. GB 3095-2012, 北京: 中国环境科学出版社, 2016. [14] ZHANG K, ZHANG D, ZHANG K, CAO Y. Capture of gas-phase arsenic by ferrospheres separated from fly ashes[J]. Energy Fuels, 2016, 30(10): 8746-8752. doi: 10.1021/acs.energyfuels.6b01637 [15] MA H, AGNIHOTRIR, CHAUK S, GHOSHDASTIDAR A, FAN L. Mechanism of arsenic sorption by hydrated lime[J]. Environ Sci Technol, 1997, 31(11): 3226-3231. doi: 10.1021/es9702125 [16] 张月, 李文瀚, 王春波, 刘慧敏, 张永生, 潘伟平.超声波辅助浸渍法制备Fe2O3/γ-Al2O3吸附剂脱除气相As2O3的实验研究[J].燃料化学学报, 2015, 43(9): 1134-1141. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18700.shtmlZHANG Yue, LI Wen-han, WANG Chun-bo, LIU Hui-min, ZHANG Yong-sheng, PAN Wei-ping. Experimental study on As2O3 capture from gas phase using ultrasound-assisted prepared Fe2O3/ Al2O3 sorbent[J]. J Fuel Chem Technol, 2015, 43(9): 1134-1141. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18700.shtml [17] ZHANG Y, LIU J. Density functional theory study of arsenic adsorption on the Fe2O3 (001) surface[J]. Energy Fuels, 2019, 33(2): 1414-1421. http://www.researchgate.net/publication/330269524_Density_Functional_Theory_Study_of_Arsenic_Adsorption_on_the_Fe2O3001_Surface [18] GAO Z, LONG H, DAI B, GAO X. Investigation of reducing particulate matter (PM) and heavy metals pollutions by adding a novel additive from metallurgical dust (MD) during coal combustion[J]. J Hazard Mater, 2019, 373: 335-346. http://www.ncbi.nlm.nih.gov/pubmed/30928676 [19] YAO H, NARUSE I. Control of trace metal emissions by sorbents during sewage sludge combustion[J]. Proc Combust Inst, 2005, 30: 3009-3016. http://www.sciencedirect.com/science/article/pii/S0082078404000505 [20] YAO H, NARUSE I. Using sorbents to control heavy metals and particulate matter emission during solid fuel combustion[J]. Particuology 2009, 7: 477-482. http://www.sciencedirect.com/science/article/pii/S1674200109000790 [21] KUO J, LIN C, WEY M. Effect of particle agglomeration on heavy metals adsorption by Al-and Ca-based sorbents during fluidized bed incineration[J]. Fuel Process Technol, 2011, 92: 2089-2098. http://www.sciencedirect.com/science/article/pii/S0378382011002347 [22] GAO Z, LONG H, DAI B, GAO X. Investigation of reducing particulate matter (PM) and heavy metals pollutions by adding a novel additive from metallurgical dust (MD) during coal combustion[J]. J Hazard Mater, 2019, 373: 335-346. http://www.ncbi.nlm.nih.gov/pubmed/30928676 [23] WANG J, ZHANG Y, WANG T, XU H, PAN W. Effect of modified fly ash injection on As, Se, and Pb emissions in coal-fired power plant[J]. Chem Eng J, 2020, 380: 122561. http://www.sciencedirect.com/science/article/pii/S1385894719319643 [24] 何梓谦, 余圣辉, 张成, 许豪, 方庆艳, 陈刚.气氛对氧化物吸附气相砷的影响及机理分析[J].洁净煤技术, 2020, 26(4): 190-195.HE Zi-qian, YU Sheng-hui, ZHANG Cheng, XU Hao, FANG Qing-yan, CHEN Gang. Effects of atmosphere on gas-phase arsenic adsorption by oxides and mechanism analysis[J]. Clean Coal Technol, 2020, 26(4): 190-195. [25] YU S, ZHANG C, MA L, TAN P, FANG Q, CHEN G. Deep insight into the effect of NaCl/HCl/SO2/CO2 in simulated flue gas on gas-phase arsenic adsorption over mineral oxide sorbents[J]. J Hazard Mater, 2021, 403: 123617. http://www.sciencedirect.com/science/article/pii/S0304389420316034 [26] YUAN C, ZHANG C, YU S, XU H, LI X, FANG Q, CHEN G. Experimental and density functional theory study of the adsorption characteristics of CaO for SeO2 in simulated flue gas and the effect of CO2[J]. Energy Fuels, 2020. https://doi.org/10.1021/acs.energyfuels.0c02044. [27] SCHWINDT VC, ARDENGHI JS, BECHTHOLD P, GONZALEZA EA, JASENA PV, JUANA A, BATICB BS, JENKO M. Selenium adsorption at different coverages on Fe (100) and Fe (111): A DFT study[J]. Appl Surf Sci, 2014, 315: 252-260. http://www.sciencedirect.com/science/article/pii/S0169433214016596 [28] FAN Y, ZHUO Y, LOU Y, ZHU Z, LI L. SeO2 adsorption on CaO surface: DFT study on the adsorption of a single SeO2 molecule[J]. Appl Surf Sci, 2017, 413: 366-371. http://www.sciencedirect.com/science/article/pii/S0169433217308772 [29] HE F, ZHOU L, ZHANG X, LI W, YANG L, ZHAO H, HE X. Synthesis and anisotropic properties of alumina-silica aerogels constructed by silica sols infiltrated into unidirectional frozen alumina templates[J]. Ceram Int, 2019, 45: 11963-11970. http://www.sciencedirect.com/science/article/pii/s0272884219306285 [30] 许豪, 张成, 袁昌乐, 余圣辉, 李权, 方庆艳, 陈刚.模拟烟气气氛下矿物元素组分对砷的吸附特性研究[J].燃料化学学报, 2019, 47(7): 876-883. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract29424.shtmlXU Hao, ZHANG Cheng, YUAN Chang-le, YU Sheng-hui, LI Quan, FANG Qing-yan, CHEN Gang. Study on arsenic adsorption characteristics by mineral elements in simulated flue gas atmosphere[J]. J Fuel Chem Technol, 2019, 47(7): 876-883. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract29424.shtml [31] CHEN D, HU H, XU Z, LIU H, CAO J, SHEN J, YAO H. Findings of proper temperatures for arsenic capture by CaO in the simulated flue gas with and without SO2[J]. Chem Eng J, 2015, 267: 201-206. http://www.sciencedirect.com/science/article/pii/S1385894715000649 [32] LIU T, XUE L, GUO X, HUANG Y, ZHENG C. DFT and experimental study on the mechanism of elemental mercury capture in the presence of HCl on α-Fe2O3(001)[J]. Environ Sci Technol, 2016, 50(9): 4863-4868. doi: 10.1021/acs.est.5b06340 [33] WANG H, CHAI Z, WANG D. Adsorption of uranyl on hydroxylated α-SiO2(001): A first-principle study[J]. Dalton Trans, 2014, 44: 1646-1655. http://www.ncbi.nlm.nih.gov/pubmed/25437449 [34] SU Q, JU X, FENG Q, SI Y. Periodic DFT study of adsorption of nitroamine molecule on α-Al2O3(0 0 1) surface[J]. Appl Surf Sci, 2012, 258(19): 7334-7342. http://www.sciencedirect.com/science/article/pii/S0169433212006472 -
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