BET资料-NOVA Install Training Module.ppt

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,NOVA e-,系列培训教程,Automated Surface Area and Pore Size Analyzer,培训指南,安装准备,安装,样品管校准,样品制备（脱气）,样品分析,数据处理,异常吸附等温线原因分析,案例分析,:,对,BET,结果的影响因素,安装准备,所需装置,Two Stage Inert,Gas Regulator,(CGA 580),With,Gas Cut-Off Valve,and,1/8”Male threaded,Swagelok,Fitting,安装准备,Required Utilities,高纯氮气,99.999%,电源,220 Volt/50 Hz,安装准备,PC,Pentium Processor,20 MB HD Space,RS232 or USB Port,Windows XP,NT,or,2000,安装准备,Liquid Nitrogen Source,and,Transfer Dewar,MAIN,气路连接,Connect Gas line to the two stage gas,regulator,(7/16”Wrench required for tightening,),Connect the other end of the gas line to the threaded gas connector fitting on the back of the NOVA.,(7/16”Wrench required for tightening),气路连接,真空管路连接,Vacuum Hose Connection,Connect vacuum hose to the back of the NOVA,Connect vacuum hose to the vacuum pump,通讯电缆连接,Communication Cable Connection,Connect RS232 cable,to the 9 Pin connectors on the PC and NOVA.,电源线连接,Power Line Connection,Plug power cord into NOVA and into a,110 V AC power source,Power Up The System,Turn on vacuum pump.,Set gas pressure at 10 psig on regulator and open gas valve.,Insert NOVA User disk.,Turn on NOVA power switch.,软件安装,Install,NOVAWin,From CD,建立,NOVA-PC,通讯,Establish NOVA To PC Communication,Open,NOVAWin,program,Select“Operation”menu and,click“Instrument Settings”,建立,NOVA-PC,通讯,Establish NOVA To PC Communication,Establish NOVA To PC Communication,Select the COM port number that,will be used for communicating,with the NOVA.,Establish NOVA To PC Communication,Select“Operation”menu and click“Instrument Status”to verify the PC is communicating with the NOVA,NOVA Status:,Stations“Idle,”,Establish NOVA To PC Communication,出现上述“空转”信息，则安装完成,！,MAIN,样品管校正,Cell Calibration,Open,NOVAWin,software,Cell Calibration,Fill,dewar,to the internal upper mark with liquid nitrogen,将液氮倒至杜瓦瓶内标刻度,Place sample cell with,filler rod into analysis station to be used for calibration!,将样品管连同填充棒装入分析站,填充棒的作用,:,减小死体积,使吸脱附等温线闭合良好,.,Cell Calibration,Select Calibrate Cell from the Operation Menu,Cell Calibration,Select“calculate Po”,option,Select gas,for calibration,Select station to be used for cell calibration,Assign a cell number(1 99)for the cell being calibrated,Choose the cell diameter size of the cell being calibrated,(6,9,12 mm),Click Start when all selections are complete.,Cell Calibration,When cell calibration is complete,proceed to sample,preparation section.,样品管校正一次即可,标准样品管不用校正,样品管校正后,进入样品准备阶段,MAIN,样品准备,称样量,:,仅进行表面积测量,:,使总表面至少在,1m,2,至,5 m,2,间。,-,吸脱附等温线,:,在管中总表面积应至少为,15-20 m,2,。,小经验,:,尽可能称重到,100mg,以上,以减少称重误差,比表面大于,1000:,称重,0.05-0.08g,比表面大于,10,小于,1000:,称重,0.1-0.5g,比表面小于,1:,称重,1g,以上,样品准备,应该使用哪种样品管,样品管类型,9 mm,样品管是最常用的样品管,适合大部分样品,.,短管仅用于,BET,分析,.,死体积小,.,标准管用于颗粒样品及常规比表面分析,.,大球样品管用于粉末样品及低表面样品分析,.,样品准备,Sample Preparation,-,先将装有样品的管球端插入加热包中,用包夹固定样品管,提示,:,脱气时不要使用填充棒,将加热包捏圆插入,有利于延长加热包的寿命,样品准备,Sample Preparation,Insert the sample cell stem into the sample preparation station.,Tighten the knurled ring by turning it clockwise to,secure the sample cell in the preparation station,.,Sample Preparation,在确保样品管安装好后,进入仪器的控制面板进行脱气初始化,3.,Control Panel,2.Degas Stations,Load Degas Stations,1)YES,Degas Type Selection,1)Vacuum Degas,Sample,cell(s,)are in place,Press enter to start!,Sample Preparation,一旦脱气站加载,先设定脱气温度,再打开加热包开关,Set,outgassing,temperature,Turn on switch,Sample Preparation,当样品脱气足够的时间,关掉加热包开关,这样加热包和样品管才能冷却,.,Turn off,Sample Preparation,3.,Control Panel,2.Degas Stations,UnLoad,Degas Stations,1)YES,Remove sample cell,and plug station.,Press enter to exit,Degas menu.,卸载,:,Once the heating mantle has,cooled,unload the out gas,station using the NOVA control,panel following these steps.,根据提示转移样品管,并,堵上,脱气站,Sample Preparation,Re-weigh the sample cell,to determine the post out gas,sample weight.,再次称重,得到脱气后样品重量,.,Proceed to the Sample Analysis,Section.,进入样品分析阶段,.,MAIN,样品分析,将液氮充至杜瓦瓶内上部的标记。,将装有脱气后称过重的已校正样品管装到分析站准备分析。,注意,:,确保在样品管中放入填充棒,!,样品分析,液位传感器的作用,(NOVA2007,版,),：,1,。减小测量死体积，提高测量精度,2,。帮助判断液氮纯度,样品温度控制,-,包括液位传感器和自动电梯的伺服反馈系统,60,小时冷阱杜瓦,液位传感器控制液位,to 0.5 mm,样品保持恒温,Thermistor,Dewar,Sample Cell,Dewar,Animation,Click,Dewar Cross Sectional View,随着液氮蒸发杜瓦上移,Dewar Moves Up As,Coolant Evaporates,总是保持冷域最小,Small Cold Zone,Always Maintained,WHY?,样品温度控制,-,包括液位传感器和自动电梯的伺服反馈系统,死体积是原来的,1/4,气体吸附,通过固体表面上气体吸附量多少来计算粉体或多孔固体的比表面积,比表面积的测量包括能够到达表面的全部气体，无论外部还是内部。,一般而言，在范德华力作用下，固体吸附 气体是弱键作用。,为了使足够气体吸附到固体表面，测量时固体必须冷却，通常冷却到吸附气体的沸点。,通常氮气作为被吸附物，因此固体被冷却到液氮温度,(77.35,K),Copyright Quantachrome Corporation 2000.All rights reserved.,如何保证液氮温度在,77K?,液氮纯度,:,必须保证纯度,P,0,200,活性碳,分子筛,含有微孔样品的,BET,计算,活性炭样品举例,:,BET,计算范围为,0.05-0.1(P/P0),多数符合,Langmiur,方程,务必使,C,值大于,0,保持回归系数优于,0.9999,含有微孔样品的,BET,计算,-ERM-FD107,(,标准值,610.6,13.8m,2,/g),Sample Analysis,Analysis,Parameter Selection,Complete fields on the Start Analysis“Equilibrium”menu!,Field defaults can be used for BET measurements!,Sample Analysis-Starting,When all fields are complete on the Start Analysis Menus,Click“,Start,”to begin the analysis.,MAIN,Data Reduction,Open the,NOVAWin,program,Data Reduction,Select Open from the File menu,Data Reduction,Select the data file(,qps,)to be reduced.,Data Reduction,The data file isotherm will appear!,Data Reduction,Right click on mouse and select“Edit data tags,”,Data Reduction,The data points for the analysis file will appear.,Data Reduction,Highlight the data points from 0.05 to 0.3 P/Po,by using ctrl and clicking the left mouse button.,Check“On”box next to the“M”.,Click Apply to selected,Data Reduction,M tags appear,Click“OK”,Data Reduction,Click on the right mouse button and,highlight:,Graphs,BET,and,Multipoint BET Plot.,Click on the,Multipoint BET Plot selection!,Data Reduction,The Multipoint BET Plot(graph),will appear.,Scroll up the graph for the BET surface area result.,Data Reduction,BET surface area results.,Repeat the same procedure,for tabular results,MAIN,异常吸附等温线原因分析,www.Q,MAIN,不要忽略纵坐标值,称样量太少,(0.08g),异常吸附等温线原因分析,www.Q,MAIN,吸附等温线,异常吸附等温线原因分析,www.Q,MAIN,不要忽略纵坐标值,称样量太少,(0.08g),BET summary,Slope=5.970,Intercept=-1.167e-01,Correlation coefficient,r=0.999196,C constant=-50.133,Surface Area=595.009,m?g,异常吸附等温线原因分析,www.Q,MAIN,不要忽略纵坐标值,称样量太少,(0.08g),Langmuir,summary,Surface Area=805.522,m?g,HOW TO HANDLE AN UNCOOPERATIVE MATERIAL,对,BET,结果的影响因素,案例,:,硬脂酸镁,Case Study:Magnesium Stearate,性质,:,CH3,（,CH2,）,16COO2Mg,又称十八酸镁。纯粹的是白色轻质粉末。密度,1.028,。熔点,88.5,。普通的是略有黄色的重质粉末。无臭。微溶于水。溶于热的乙醇。遇强酸能分解成硬脂酸和相应的镁盐。用作塑料制品的稳定剂、药片的粉模剂、油漆的催化剂和平光剂、化妆品香粉的原料等。,有一定紧密度,硬度,.,报告的比表面从,3.53 to 53.6 m,2,/g,大多数报道的,数值在,4 to 10 m,2,/g,之间,.,由于脱气条件的不同测出的比表面值总是变化,.,文献指出,:,真空或流动脱气不得高于,35 or 40 C.,硬脂酸镁氮吸附,BET,的,C,常数很低,(3 15).,必须特别小心地确保足够的吸附时间以使各个点达到完全平衡,.,案例,:,硬脂酸镁,Case Study:Magnesium Stearate,认识非平衡的状态,Identifying Under-Equilibration,舍弃非平衡的数据点,(at low P/Po),绝对不要少于三个数据点,一般至少,5,个点,.,多点,BET,图,(,处理,),用等距或近似等距的数据点,.,确认,BET,需要在较高的,P/Po,值下计算,.,硬脂酸镁比表面测定困难的原因,样品的含水量,:,因潮湿空气而老化,;,BET,比表面值因样品含水量增加而增加,;,除了该材料在极低水含量下的氪吸附外,观察到的所有情况都是吸附量变化大和迟滞环不正常,.,迟滞环形状及变化不能认为有毛细管凝聚作用,Cyrille,Andres,Pierre,Bracconi,Yvette,Pourcelot,International Journal of Pharmaceutics,218,(2001)153163,Mag,.Stearate,Thermograms,Temperature(,degC,),Outgassed,105,degC,Moisture,6 weeks,Outgassed,60,degC,As received,Mikko,Koivisto,Hannu,Jalonen,and,Ensio,Laine,比表面与脱气温度的关系,(He flow,24 hours),D.S.Phadke,and J.L.,Coller,Drug Dev.Ind.,Pharm,.,20,(5)853-858(1994),比表面与脱气时间的关系,40,degC,Private communication,unpublished data(1999),Non-bovine Magnesium Stearate,isotherm,BET plot,Zinc Stearate,isotherm,BET plot,BET,比表面计算方法的限制,这类样品在极低压力下有,III,等温线的特征,但在正常,BET,区间显示了一个增强的吸附,增强的吸附,这个现象归因于一个协同的吸附过程,即临界尺寸的裂隙孔,水在炭上,(,疏水表面,),是一个典型例子,