introducing the sa-9600 flowing gas bet surface area analyzer
DESCRIPTION
Dr. Michael Pohl of HORIBA Particle presents information about the SA-9600 series of surface area analyzers.TRANSCRIPT
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State-of-the-Art BET Surface AreaAn Introduction to the SA-9600 Technology
Mike [email protected]
www.horiba.com/us/particle
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Surface Area Basics
The BET Technique
Measurement Workflow
Recent Advancements
Outline
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Surface Area Basics
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Why Surface Area?
Rates of…
DissolutionReactionAbsorption/adsorptionCombustionHydration
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Non-porous solidLow specific surface areaLow specific pore volume
Porous solidHigh specific surface areaHigh specific pore volume
Porous materials have highly developed internal surface area that can be used to perform a specific function. Almost all solids have some amount of porosity.
Porosity
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Pore size and its distribution
Specific Surface Area, m2/g =
Porosity
There are three parameters used to measure porosity; specific surface area, specific pore volume or porosity, and pore size and its distribution.
Mass of the solid, g
Total surface area, m2
Specific Pore volume, cm3/g
Mass of the solid, g
Total pore volume, cm3
=
Porosity, % =
Volume of solid (including pores)
Volume of poresX 100
Porosity
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2 nm 50 nm
Micropores Mesopores Macropores
Zeolite,Activated carbon,Metal organicframework
Mesoporous silica, Activated carbon
Sintered metals and ceramics
Pore Size
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ABsorptionGas molecules penetrate mass of a solid
ADsorptionGas molecules condense on free surfaces
PhysisorptionPhysical adsorption - van der Waals forces
ChemisorptionChemical adsorption – chemical bonding
ABsorption
ADsorption
Definitions
Note: Flowing-gas method uses physisorption
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Physisorption
Weak, long-rangeNot surface specificLower energy of Ads.Desorption increases with increasing temp.Non-reactive at surfaceMultilayer adsorption (BET used to model)
Chemisorption
Strong, short-rangeSurface specificHigher energy of Ads.Adsorption can increase with temp.Potentially reactive at surfaceMonolayer adsorption (Langmuir model)
Comparison
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Physisorption Behavior
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W t
P / P0
Type 1
Chemisorption
W t
P / P0
Type 2
Non-porous or macropore
powders
W t
P / P0
Type 3
W t
P / P0
Type 4
Porous Powders
W t
P / P0
Type 5
Isotherm Types
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Type IV Isotherm
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The BET Technique
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BET Calculation
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BET Calculation
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Single-point method offers the advantage of simplicity and speed, with acceptable accuracy.
( )oam PPVV −= 1 i.e. Vm = 1/slope
A relative pressure of 0.3 gives good general agreement with the multi-point method.
Correction of single point “error” at P/P0 = 0.3 by multiplying the single point BET value by C/C-2 decreases the difference.
Sample No.
Multi-point BET
(m2/g)
Uncorrected single-point
(m2/g)
Uncorrecteddifference
(%)
Corrected single –
point(m2/g)
Correcteddifference
(%)
1 4.923 4.241 -13.9 4.948 0.51
2 4.286 3.664 -14.5 4.275 -0.263 8.056 6.867 -14.8 8.011 -0.564 5.957 5.194 -12.8 6.060 +1.73
Effect of Multipoint
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Method Comparison
Dynamic (Flowing-Gas)
FasterEasy to useIncreased sensitivity to low SSA materialsHigher throughputLower operating costsLower service costs
Static-Volumetric
SlowerEasy to useLow SSA longer measurement timesLower throughputHigher operating costsHigher service costs
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Measurement Workflow
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Outgassing station
Analysis stations
Liquid nitrogen bath
The SA-9600 Surface Area Analyzer
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What You’ll Need
Gases99.999% pure Helium99.999% pure NitrogenDry gas
Liquid NitrogenCools material surface for adsorption
Mass BalanceInstrument measures total surface area, sample mass is used to convert to SSA
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Workflow
PreparationCheck gas flowConfirm temperature and pressureWeigh sample (know how much)Degas sample (prepare clean surfaces)
MeasurementAutomatic calibrationAutomatic adsorption and desorptionAutomatic calculation of specific surface areaSave, Export, Print report
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Recent Advancements
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Easy to Use SoftwareMulti-tasking – View, Edit and Print Data while Measuring.Measure and Display Window – Similar to LA Products
SA-9600 Software
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5 Measurement Types 3 Gas Mixture Points6 Gas Mixture Points13 point Pore Size Dist.Pore Volume – Multiple RunsSingle Point – Multiple Runs
Data Graphed on Screen and Reports
SA-9600 Software
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Real-time Measurement
Calibration
Adsorption
Desorption
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User Name and Password to Login to SoftwareBuilt-in Security with Users and GroupsSetup Security SettingsHoriba Provides Master System Administration Key to Unlock System
SA-9600 Security Module
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Audit Trail capabilityElectronic Signature on reportsAnalyzer must be controlled from computerCertain events require a User name and Password
21 CFR Part 11 Compliance
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Electronic Signature is the information printed at the Bottom of the report that is automatically generated based on information stored in the file and the current user.
Electronic Signature
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Audit Trail
Audit Trail contains all events related to the creation of data files, editing conditions, printing, etc. It also logs system access information such as login name, login time, and bad passwords.
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For More Details
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Contact us directly at [email protected]
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