沸石晶体SAPO-34特殊的螺旋式生长结构研究
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摘要
目的研究硅磷酸铝沸石在不同模板剂条件下的形貌特征,并寻求控制晶体形貌的方法,分析其生长机制及原理,并获得其形貌控制的规律.方法配制去离子水与磷酸的混合溶液,加入铝源拟薄水铝石,搅拌至完全溶解,再加入吗啉并搅拌,加入硅源白炭黑至产生均匀凝胶,加入适量氢氟酸,将凝胶转入配有聚四氟乙烯内衬的反应釜中晶化,过滤出固体产物,并用去离子水反复洗涤,放入烘箱干燥,并检测其XRD谱线、核磁谱线、扫描电镜图像及原子力显微镜图像.结果当n(HF)∶n(Al_2O_3)=0.4时,能够得到完整的螺旋式生长结构晶体,样品形貌最佳.结论氢氟酸中的氟离子通过与SAPO-34中的铝原子结合,一定程度上阻止了磷原子和铝原子的配位,改变了SAPO-34常规的层状生长机理,产生了特殊的螺旋式生长结构.
The morphology characteristics of silicon aluminum phosphate zeolites under different templates were studied to seek for ways to control the crystal morphology.The mechanism and principles behind its growth were analyzed.And the key rules governing morphology control were acquired.The special zeolite crystals SAPO-34 was prepared by first mixing the deionized water with phosphoric acid and together with the aluminum source(pseudoboehmite).Then morpholine was successively added into the above mixture.After that the silicon source(fumed silica) was added slowly to the mixture.To make spiral growth structure of SAPO-34,subsequently,a certain a-mount of hydrofluoric acid(HF) was added at the end of the preparation.The final solution was loaded into the stainless steel autoclave.The product was separated and washed with deionized water for several times and then dried.Then the properties were investigated via in-situ X-ray diffraction(XRD),nuclear magnetism resonance(NMR),scanning electron microscopy(SEM),and atomic force microscopy(AMF).The experimental results indicate that when n(HF) ∶ n(Al_2O_3) =0.4,the SAPO-34 crystals have the best and most complete of spiral shapes.The special spiral growth structure of zeolite crystals SAPO-34 observed in this study is attributed to the combination of fluoride ions and aluminum atoms,then partly stopping the coordination of phosphorus and aluminum atoms.So regular layer structure is changed and special spiral growth structure of zeolite crystals SAPO-34 is formed.
The morphology characteristics of silicon aluminum phosphate zeolites under different templates were studied to seek for ways to control the crystal morphology.The mechanism and principles behind its growth were analyzed.And the key rules governing morphology control were acquired.The special zeolite crystals SAPO-34 was prepared by first mixing the deionized water with phosphoric acid and together with the aluminum source(pseudoboehmite).Then morpholine was successively added into the above mixture.After that the silicon source(fumed silica) was added slowly to the mixture.To make spiral growth structure of SAPO-34,subsequently,a certain a-mount of hydrofluoric acid(HF) was added at the end of the preparation.The final solution was loaded into the stainless steel autoclave.The product was separated and washed with deionized water for several times and then dried.Then the properties were investigated via in-situ X-ray diffraction(XRD),nuclear magnetism resonance(NMR),scanning electron microscopy(SEM),and atomic force microscopy(AMF).The experimental results indicate that when n(HF) ∶ n(Al_2O_3) =0.4,the SAPO-34 crystals have the best and most complete of spiral shapes.The special spiral growth structure of zeolite crystals SAPO-34 observed in this study is attributed to the combination of fluoride ions and aluminum atoms,then partly stopping the coordination of phosphorus and aluminum atoms.So regular layer structure is changed and special spiral growth structure of zeolite crystals SAPO-34 is formed.
引文
[1]BARAKOV R,SHCHERBAN N,YAREMOV P.Low-temperature and alkali-free dual template synthesis of micro-mesoporous aluminosilicates based on precursors of zeolite ZSM-5[J].Journal of materials science,2016,51(8):4002-4020.
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[10]MITTAL N,PENG B,KELLOWAY A.A mathematical model for zeolite membrane module performance and its use for techno-economic evaluation of improved energy efficiency hybrid membrane-distillation processes for butane isomer separations[J].Journal of membrane science,2016,520:434-449.
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[12]YOU Y,YU X,YIN Y.Sodium iron hexacyanoferrate w ith high Na content as a Na-rich cathode material for Na-ion batteries[J].Nano research,2015,8(1):1-12.
[13]HAMIDI F,BOUKLI-HACENE F,CACCIAGUERRA T.Nucleation promotion of zeolite crystals by in situ formation of silver-based heterogeneous nuclei[J].M icroporous&mesoporous materials,2012(153):59-62.
[14]SANCHEZ M,DIIAZ R,CORDOVA T.Study of template interactions in M FI and M EL zeolites using quantum methods[J].M icroporous&mesoporous materials,2015,203:91-99.
[15]BEALE A,O'BRIEN M,KASUNIC M.Probing Zn APO-34 self-assembly using simultaneous multiple insitu techniques[J].Journal of physical chemistry C,2011,115(14):6331-6340.
[16]LIU G,HUNG W S,SHEN J.Mixed matrix membranes w ith molecular-interaction-driven tunable free volumes for efficient bio-fuel recovery[J].Journal of materials chemistry A,2015,3(8):4510-4521.
[17]SHAKAROVA D,OJUVA A,BERGSTROM L.M ethylcellulose-directed synthesis of nanocrystalline zeolite Na A w ith high CO2uptake[J].Materials,2014,7(8):5507-5519.
[18]佟钰,夏枫,张婷.微波加热对地聚物砂浆力学强度的影响[J].沈阳建筑大学学报(自然科学版),2015(2):313-319.(TONG Yu,XIA Feng,ZHANG Ting.Influence of microw ave heating on mechanical strength of geopolymer-based mortar[J].Journal of Shenyang jianzhu university(natural science),2015(2):313-319.)
[19]WOODRUFF D.How does your crystal grow?A commentary on burton,cabrera and frank(1951)'the growth of crystals and the equilibrium structure of their surfaces'[J].Philosophical transactions of the royal society a mathematical physical&engineering sciences,2015,373(2039):1-11.
[20]赵苏,左明贺,王倩.改性超细氧化铝对抛光磨料耐磨性的影响[J].沈阳建筑大学学报(自然科学版),2011,27(3):530-534.(ZHAO Su,ZUO Minghe,WANG Qian.Surface modification of ultra-fine Al2O3and its effect on friction resistance of polishing abrasive[J].Journal of Shenyang jianzhu university(natural science),2011,27(3):530-534.)
[2]FUKUSHIMA K,FINA A,GEOBALDO F.Properties of poly(lactic acid)nanocomposites based on montmorillonite,sepiolite and zirconium phosphonate[J].Express polymer letters,2012,6(11):914-926.
[3]CHEN X,XI D,SUN Q.A top-down approach to hierarchical SAPO-34 zeolites w ith improved selectivity of olefin[J].M icroporous&mesoporous materials,2016,234:401-408.
[4]YU J,XIAO F,CORMA A.Preface to special issue on zeolite materials and catalysis[J].Chinese journal of catalysis,2015,36(6):787-788.
[5]GKANAS E,STERIOTIS T,STUBOS A.A complete transport validated model on a zeolite membrane for carbon dioxide permeance and capture[J].Applied thermal engineering,2014,74:36-46.
[6]JIANG J,WANG X,ZHANG Y.Fabrication of pure-phase CHA zeolite membranes w ith ballmilled seeds at low K+concentration[J].M icroporous&mesoporous materials,2015,215:98-108.
[7]ZHU X,ROHLING R,FILONENKO G.Synthesis of hierarchical zeolites using an inexpensive mono-quaternary ammonium surfactant as mesoporogen[J].Chemical communications,2014,50(93):14658-14661.
[8]ZHANG K,OSTRAAT M.Innovations in hierarchical zeolite synthesis[J].Catalysis today,2015,264:3-15.
[9]BOULFELFEL S,RAVIKOVITCH P,SHOLL D.M odeling diffusion of linear hydrocarbons in silica zeolite LTA using transition path sampling[J].Journal of physical chemistry C,2015,119(27):15643-15653.
[10]MITTAL N,PENG B,KELLOWAY A.A mathematical model for zeolite membrane module performance and its use for techno-economic evaluation of improved energy efficiency hybrid membrane-distillation processes for butane isomer separations[J].Journal of membrane science,2016,520:434-449.
[11]SANABRIA N,MOLINA R,MORENO S.Development of pillared clays for w et hydrogen peroxide oxidation of phenol and its application in the posttreatment of coffee w astew ater[J].International journal of photoenergy,2012,226(24):1069-1075.
[12]YOU Y,YU X,YIN Y.Sodium iron hexacyanoferrate w ith high Na content as a Na-rich cathode material for Na-ion batteries[J].Nano research,2015,8(1):1-12.
[13]HAMIDI F,BOUKLI-HACENE F,CACCIAGUERRA T.Nucleation promotion of zeolite crystals by in situ formation of silver-based heterogeneous nuclei[J].M icroporous&mesoporous materials,2012(153):59-62.
[14]SANCHEZ M,DIIAZ R,CORDOVA T.Study of template interactions in M FI and M EL zeolites using quantum methods[J].M icroporous&mesoporous materials,2015,203:91-99.
[15]BEALE A,O'BRIEN M,KASUNIC M.Probing Zn APO-34 self-assembly using simultaneous multiple insitu techniques[J].Journal of physical chemistry C,2011,115(14):6331-6340.
[16]LIU G,HUNG W S,SHEN J.Mixed matrix membranes w ith molecular-interaction-driven tunable free volumes for efficient bio-fuel recovery[J].Journal of materials chemistry A,2015,3(8):4510-4521.
[17]SHAKAROVA D,OJUVA A,BERGSTROM L.M ethylcellulose-directed synthesis of nanocrystalline zeolite Na A w ith high CO2uptake[J].Materials,2014,7(8):5507-5519.
[18]佟钰,夏枫,张婷.微波加热对地聚物砂浆力学强度的影响[J].沈阳建筑大学学报(自然科学版),2015(2):313-319.(TONG Yu,XIA Feng,ZHANG Ting.Influence of microw ave heating on mechanical strength of geopolymer-based mortar[J].Journal of Shenyang jianzhu university(natural science),2015(2):313-319.)
[19]WOODRUFF D.How does your crystal grow?A commentary on burton,cabrera and frank(1951)'the growth of crystals and the equilibrium structure of their surfaces'[J].Philosophical transactions of the royal society a mathematical physical&engineering sciences,2015,373(2039):1-11.
[20]赵苏,左明贺,王倩.改性超细氧化铝对抛光磨料耐磨性的影响[J].沈阳建筑大学学报(自然科学版),2011,27(3):530-534.(ZHAO Su,ZUO Minghe,WANG Qian.Surface modification of ultra-fine Al2O3and its effect on friction resistance of polishing abrasive[J].Journal of Shenyang jianzhu university(natural science),2011,27(3):530-534.)