Visualization study on preparation of CeO2 by pyrolysis method via microwave heating
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摘要: 針對傳統液相法制備氧化鈰納米顆粒存在工藝流程復雜、高污水排放等問題，提出了一種高效綠色的實驗方案，以七水合氯化鈰為原料，采用微波射流熱解技術制備出了高純度氧化鈰納米顆粒。通過X射線衍射儀(XRD)、掃描電鏡(SEM)和能譜儀(EDS)分析手段對產物進行了表征，借助數值模擬手段可視化分析了各物理場、各組分分布。考察了不同工藝條件（熱解溫度、氣相速度、和添加檸檬酸）對實驗產物中殘余氯根含量和產物微觀形貌的影響。結果表明，熱解溫度達到500 ℃時便可獲得單相氧化鈰，溫度越高氧化鈰純度越高，顆粒形貌越規則。增大氣相入口速度導致產物殘余氯根增多，但有利于改善顆粒團聚。添加檸檬后氧化鈰從球狀顆粒逐漸破碎為伴有少量多孔結構的不規則形狀顆粒，顆粒比表面積增大。檸檬酸濃度大于0.1 mol?L?1后利于減少氯根含量。Abstract: Preparation of cerium oxide by conventional liquid phase method has the disadvantages of complex technological process and effluent discharge. Spray pyrolysis for making CeO2 has the disadvantages of nozzle plugging, and this traditional heating method produces a significant temperature gradient that results in unevenly heated reactants. To prevent the above issues, this study proposed an effective and environmental experimental scheme. Cerium chloride heptahydrate and deionized water were utilized for the raw material. High-purity nano cerium oxide particles were prepared by jet-flow pyrolysis technology via microwave heating. Combining the technology of microwave heating with jet-flow pyrolysis, whose Venturi reactor served as the primary piece of equipment, can improve the mixing of gas and liquid, increase chemical reaction efficiency, and reduce carbon emissions. It was a new effort in the area of pyrolysis. To visually analyze the distribution of each physical field and substance, numerical simulation was combined with x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy to characterize the products. Effects of the various technological conditions (pyrolysis temperature, gas velocity, and adding citric acid) on the content of residual chloride element and microstructure of the product were examined. Results demonstrated that the temperature error between the experiment and simulation was below 20 ℃ with the condition of the same microwave power. When the pyrolysis temperature was at 500 ℃, CeO2 could be produced in a single phase, but the particle profile was unclear. The particles had sharp profiles when the temperature was 600 ℃. Nanoscale spherical CeO2 particles appeared when the average temperature reached 700 ℃. The results of the study’s simulations and experiments indicated that higher temperatures were associated with more regular microcosmic morphology and a lower content of residual chloride element. Increasing the gas velocity caused an obvious decrease in the average temperature, which led to more content of residual chloride elements. However, the gas collided with the solution more fiercely, which improved the mixing of the two phases. Experimental and simulated results showed that when gas velocity reached 1.2 m?s?1, better dispersity and less agglomeration of the product were obtained. Additionally, the residual chloride content was less than 1%. Because a significant amount of CO2 was produced during the burning of the citric acid, the spherical cerium oxide particles broke into irregular particles. Porous structures also appeared when citric acid was added. The residual chloride content decreased with the increase of citric acid concentration when citric acid concentration was greater than 0.05 mol?L?1.
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Key words:
- microwave heating /
- jet-flow pyrolysis /
- cerium oxide /
- numerical simulation /
- venturi
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圖 2 三維模型及物性參數. (a) 三維模型; (b) 介電常數和損耗因子隨溫度變化曲線; (c) 電導率、熱導率和比熱隨溫度變化曲線
Figure 2. Three-dimensional model and major physical parameters of CeCl3 solution: (a) three-dimensional model; (b) curves of dielectric constant and loss factor; (c) curves of conductivity, thermal conductivity, and specific heat
圖 3 不同溫度條件下CeO2的SEM照片. (a) 500 ℃; (b) 600 ℃; (c) 700 ℃; (d) 800 ℃
Figure 3. SEM images of CeO2: (a) 500 ℃; (b) 600 ℃; (c) 700 ℃; (d) 800 ℃
圖 4 實驗驗證和產物XRD圖譜. (a) 產物XRD圖譜; (b) 實驗與模擬結果對比
Figure 4. Experimental verification and XRD pattern of product: (a) XRD patterns of product; (b) comparison between experimental and simulated results
圖 5 不同溫度下反應器內溫度場和CeO2組分分布. (a) 溫度場分布; (b) CeO2組分分布
Figure 5. Temperature field and CeO2 distribution: (a) temperature field; (b) CeO2 distribution
圖 6 不同氣速條件下CeO2的SEM照片. (a) 0.9 m?s?1; (b) 1 m?s?1; (c) 1.1 m?s?1; (d) 1.2 m?s?1
Figure 6. SEM images of CeO2 when gas velocity changed: (a) 0.9 m?s?1; (b) 1 m?s?1; (c) 1.1 m?s?1; (d) 1.2 m?s?1
圖 7 氣相速度的影響. (a) 實驗XRD衍射圖譜; (b) 模擬結果
Figure 7. Effects of gas velocity: (a) XRD patterns of product; (b) simulated results
圖 8 添加C6H8O7后CeO2的SEM照片. (a) 0.05 mol?L?1; (b) 0.1 mol?L?1; (c) 0.15 mol?L?1; (d) 0.2 mol?L?1
Figure 8. SEM Images of CeO2 after adding C6H8O7: (a) 0.05 mol?L?1; (b) 0.1 mol?L?1; (c) 0.15 mol?L?1; (d) 0.2 mol?L?1
圖 9 添加C6H8O7的影響. (a) 添加C6H8O7后XRD衍射圖譜; (b) 實驗與模擬結果對比
Figure 9. Effects of adding citric acid: (a) XRD patterns of product;(b) comparison between simulated and experimental results
中文字幕在线观看表 1 設備信息
Table 1. Equipment information
Equipment Model Manufacturer Measured parameters Microwave network analyzer AgilentN5224 Agilent Dielectric constant Conductivity meter DDS-11A Inesa Conductivity Thermal conductivity meter DRP-II Xiangtan Thermal conductivity Differential scanning calorimeter DSC 214 Netzsch Specific heat 
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參考文獻
[1] Tang H M, Li Q, Huang Z X, et al. Fabricate methodology research progress of CeO2 with nanostructures. Energy Res Manag, 2021(3): 18 doi: 10.16056/j.2096-7705.2021.03.005唐紅梅, 李琴, 黃振雄, 等. 二氧化鈰納米結構的制備方法研究進展. 能源研究與管理, 2021(3):18 doi: 10.16056/j.2096-7705.2021.03.005 [2] Wu W Y, Xue S F, Bian X, et al. Study on the preparation process for CeO2 superfine powder. J Northeast Univ Nat Sci, 2015, 36(6): 800 doi: 10.3969/j.issn.1005-3026.2015.06.010吳文遠, 薛首峰, 邊雪, 等. 超細氧化鈰制備工藝研究. 東北大學學報(自然科學版), 2015, 36(6):800 doi: 10.3969/j.issn.1005-3026.2015.06.010 [3] Mohan S, Dinesha P. Performance and emissions of biodiesel engine with hydrogen peroxide emulsification and cerium oxide (CeO2) nanoparticle additives. Fuel, 2022, 319: 123872 doi: 10.1016/j.fuel.2022.123872 [4] Dinesha P, Kumar S, Rosen M A. Effects of particle size of cerium oxide nanoparticles on the combustion behavior and exhaust emissions of a diesel engine powered by biodiesel/diesel blend. Biofuel Res J, 2021, 8(2): 1374 doi: 10.18331/BRJ2021.8.2.3 [5] Liu R Z, Zhou F, Wang Q C, et al. Research progress of CeO2-based electrolytes for solid oxide fuel cells. Mater Rep, 2021, 35(Suppl 1): 29劉潤澤, 周芬, 王青春, 等. 固體氧化物燃料電池用CeO2基電解質的研究進展. 材料導報, 2021, 35(增刊 1):29 [6] Venkataramana K, Madhuri C, Madhusudan C, et al. Influence of La3+, Sm3+ and Dy3+ dopants on ceria solid electrolytes for IT–SOFCs. Mater Sci Semicond Process, 2022, 142: 106495 doi: 10.1016/j.mssp.2022.106495 [7] Gong Y L, Cui C, Wu M P. Effect of Nano-CeO2 content on microstructure and corrosion resistance of Ni60A coating. Laser Optoelectron Progr, 2021, 58(21): 190龔玉玲, 崔宸, 武美萍. 納米CeO2含量對Ni60A涂層組織及耐腐蝕性能的影響. 激光與光電子學進展, 2021, 58(21):190 [8] Xu H H, Lin C, Liu J, et al. Effect of CeO2 adding content on microstructure and properties of laser cladding WC reinforced nickel-based alloy coating. Mater Mech Eng, 2021, 45(7): 27 doi: 10.11973/jxgccl202107006徐歡歡, 林晨, 劉佳, 等. CeO2加入含量對激光熔覆WC增強鎳基合金涂層組織與性能的影響. 機械工程材料, 2021, 45(7):27 doi: 10.11973/jxgccl202107006 [9] Zhang Y T. Ceria Based Nanozymes: Synthesis and Tumor Therapy Application [Dissertation]. Nanjing: Nanjing University of Posts and Telecommunications, 2021張玉濤. 氧化鈰基納米酶的制備及其在腫瘤治療方面的應用研究[學位論文]. 南京: 南京郵電大學, 2021 [10] Lu Y Q. Coagulation disorders following an accidental ingestion of cerium dioxide nanoparticles. Environ Toxicol Pharmacol, 2021, 82: 103560 doi: 10.1016/j.etap.2020.103560 [11] Zhou G Y, Zeng Y W, Huang Z Q, et al. Study on preparation of micrometer ceria used ammonium bicarbonate-ammonium hydroxide-oxalic acid by co-precipitation method. New Chem Mater, 2012, 40(9): 138 doi: 10.3969/j.issn.1006-3536.2012.09.046周國永, 曾一文, 黃志強, 等. 碳酸氫銨?氨水?草酸共沉淀法制備微米稀土CeO2工藝的研究. 化工新型材料, 2012, 40(9):138 doi: 10.3969/j.issn.1006-3536.2012.09.046 [12] Zhu S M, Qiu J S, Jiang Y L. Preparation of CeO2 nanoparticles by ion exchange homogenous precipitation method. J Dalian Univ Technol, 2010, 50(2): 167 doi: 10.7511/dllgxb201002003朱少敏, 邱介山, 姜玉玲. 離子交換均勻沉淀法合成納米CeO2研究. 大連理工大學學報, 2010, 50(2):167 doi: 10.7511/dllgxb201002003 [13] Wang F, Yang Y Q, Xue X P. Preparation and growth mechanism of CeO2 particles with controlled morphology via microwave assisted sol-gel method. J Shaanxi Univ Sci Technol Nat Sci, 2013, 31(3): 33王芬, 楊彥青, 薛緒平. 微波輔助溶膠?凝膠法制備CeO2粉體及其生長機制研究. 陜西科技大學學報(自然科學版), 2013, 31(3):33 [14] Pinar Go¨kdemir F, Evrim Saatci A, O¨zdemir O, et al. Structural, optical and electrochromic properties of cerium dioxide thin films prepared by sol-gel dip coating method. Mater Sci Semicond Process, 2015, 38: 300 doi: 10.1016/j.mssp.2014.08.037 [15] Liu Z Q, Liang Z F, Li X Y. Synthesis of nanometer cerium oxide by precipitation with ammonium bicarbonate. Chin Rare Earths, 2006, 27(5): 11 doi: 10.3969/j.issn.1004-0277.2006.05.003劉志強, 梁振鋒, 李杏英. 碳銨沉淀法制備納米氧化鈰的研究. 稀土, 2006, 27(5):11 doi: 10.3969/j.issn.1004-0277.2006.05.003 [16] Yang G S, Bian X, Cui L X, et al. Study on preparation of nano cerium oxide powder by spray roasting of cerium chloride solution. Chin Rare Earths, 2017, 38(1): 72楊國勝, 邊雪, 崔凌霄, 等. 氯化鈰溶液噴霧焙燒制備納米氧化鈰實心粉體的研究. 稀土, 2017, 38(1):72 [17] Wen Y M, Shi Z Y, Wang S L, et al. Pyrolysis of raw and anaerobically digested organic fractions of municipal solid waste: Kinetics, thermodynamics, and product characterization. Chem Eng J, 2021, 415: 129064 doi: 10.1016/j.cej.2021.129064 [18] Wen Y M, Wang S L, Mu W Z, et al. Pyrolysis performance of peat moss: A simultaneous in-situ thermal analysis and bench-scale experimental study. Fuel, 2020, 277: 118173 doi: 10.1016/j.fuel.2020.118173 [19] Liu X H. Study on the Cerium Oxide Prepared by Pyrolysis of Cerium Chloride Solution [Dissertation]. Shenyang: Northeastern University, 2011劉曉輝. 氯化鈰溶液熱解制備氧化鈰的研究[學位論文]. 沈陽: 東北大學, 2011 [20] Li R, Xia Y, Xu L, et al. Study of rapidly synthesis of ZnO nanorods by microwave hydrothermal method and photocatalytic performance. Chin J Eng, 2020, 42(1): 78李蕊, 夏仡, 許磊, 等. 微波水熱法快速合成氧化鋅納米棒及其光催化性能. 工程科學學報, 2020, 42(1):78 [21] Wang F, Zhu H B, Li Y Y, et al. Microwave heating mechanism and self-healing performance of scrap tire pyrolysis carbon black modified bitumen. Constr Build Mater, 2022, 341: 127873 doi: 10.1016/j.conbuildmat.2022.127873 [22] Wang Z H, Bai E, Huang H, et al. Study on the electromagnetic property and microwave heating efficiency of concrete with magnetite aggregate. Constr Buid Mater, 2022, 342: 128080 doi: 10.1016/j.conbuildmat.2022.128080 [23] Fia A Z, Amorim J. Heating of biomass in microwave household oven - A numerical study. Energy, 2021, 218: 119472 doi: 10.1016/j.energy.2020.119472 [24] Lv C, Yin H X, Liu Y L, et al. Preparation of cerium oxide via microwave heating: research on effect of temperature field on particles. Crystals, 2022, 12(6): 843 doi: 10.3390/cryst12060843 [25] Ouyang C, Zang B, Chen L. Preparation of ultrafine cerium oxide in microwave mode. World Nonferrous Met, 2021(20): 111 doi: 10.3969/j.issn.1002-5065.2021.20.050歐陽成, 臧兵, 陳龍. 在微波模式下制備超細氧化鈰. 世界有色金屬, 2021(20):111 doi: 10.3969/j.issn.1002-5065.2021.20.050 [26] Chen J, Hao J J, Wang C L, et al. Solid-phase decarburization of high-carbon ferrochrome powders containing calcium carbonate by microwave heating. J Univ Sci Technol Beijing, 2014, 36(12): 1626 doi: 10.13374/j.issn1001-053x.2014.12.009陳津, 郝赳赳, 王晨亮, 等. 微波加熱內配碳酸鈣高碳鉻鐵粉固相脫碳. 北京科技大學學報, 2014, 36(12):1626 doi: 10.13374/j.issn1001-053x.2014.12.009 [27] Chen H. Study on Preparation and Mechanism of Yttria-Stabilized Zirconia Nanosized Powder by Microwave Pyrolysis [Dissertation]. Zhengzhou: Zhengzhou University, 2014陳浩. 微波熱解制備氧化鋯納米粉體的工藝及機理研究[學位論文]. 鄭州: 鄭州大學, 2014 [28] Jin R. Practical Basic Research on Application of Jet Reaction in the Preparation of Rare Earth Compounds [Dissertation]. Shenyang: Northeastern University, 2015金銳. 射流反應在稀土化合物制備中的應用基礎研究[學位論文]. 沈陽: 東北大學, 2015 [29] Zhu J Y, Yi L P, Yang Z Z, et al. Three-dimensional numerical simulation on the thermal response of oil shale subjected to microwave heating. Chem Eng J, 2021, 407: 127197 doi: 10.1016/j.cej.2020.127197 -
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