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Micromeritics’ ASAP 2020® Accelerated Surface Area and Porosimetry analyzer uses the static volumetric technique to generate high-quality data for research and quality control applications. Available options include the micropore option, the high-vac option, and the hydrocarbon vapor option. The chemisorption version determines the percent metal dispersion, active metal surface area, size of active particles, and surface acidity of catalyst materials. Data obtained by an ASAP 2020 analyzer is used to achieve efficiency, safety, quality, and profitability in any modern materials-oriented work, and can be used by scientists with confidence and assurance.
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Active Surface Area by Chemisorption
Catalysts are used in a variety of applications from the production of consumer goods to the protection of the environment. Optimum design and efficient utilization of catalysts require a thorough understanding of the surface structure and surface chemistry of the active material.
Chemical adsorption (chemisorption) analysis techniques provide much of the information necessary to evaluate catalyst materials in the design and production phases, as well as after a period of use. Catalytic activity is evaluated by measuring the amounts and types of reactive gas adsorbed. This volume of gas, along with an understanding of the reaction stoichiometry, is used to calculate metal dispersion, active surface area, size of crystallites, and surface acidity.
Micromeritics instruments are specifically designed for the highly aggressive environment present during chemisorption analysis. Internal components are constructed of highest-quality stainless steel to prevent reactivity with most commonly used chemisorptives. Heated manifolds, gas lines, and detectors are provided to allow analysis with condensable vapors. Sample preparation occurs in situ to prevent contamination prior to analysis. Samples can be prepared at high temperatures (up to 1100 deg C) and at low pressures (<10 -5 mmHg).
A Short Bibliography of Researchers Using Micromeritics’ Gas Sorption Analyzers to Study Metal Organic Frameworks
Features
Two Independent vacuum systems that allow preparation and analysis to proceed concurrently,
Oil-free “dry” vacuum option to prevent oil contamination
Two-station intelligent degas system for fully automated degassing with controlled heating time profiles, an extra long duration cryogen system for unattended analyses,
Twelve gas inlets that are automatically selectable to allow for automated selection of pretreatment, backfill, and analysis gases, and the ability to connect to a mass spectrometer.
Technique Overview
The basics of the analytical technique are simple; a sample contained in an evacuated sample tube is cooled (typically) to cryogenic temperature, then is exposed to analysis gas at a series of precisely controlled pressures. With each incremental pressure increase, the number of gas molecules adsorbed on the surface increases. The pressure at which adsorption equilibrium occurs is measured and the universal gas law is applied to determine the quantity of gas adsorbed.
As adsorption proceeds, the thickness of the adsorbed film increases. Any micropores in the surface are quickly filled, then the free surface becomes completely covered, and finally larger pores are filled. The process may continue to the point of bulk condensation of the analysis gas. Then, the desorption process may begin in which pressure systematically is reduced resulting in liberation of the adsorbed molecules. As with the adsorption process, the changing quantity of gas on the solid surface is quantified. These two sets of data describe the adsorption and desorption isotherms. Analysis of the isotherms yields information about the surface characteristics of the material.
Major Accessory Literature:
Vapor Option / Water Vapor Option
General
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Pressure Measurement:
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Range: 0 to 950 mmHg
Resolution:
- 1000-mmHg Transducer: 0.001 mmHg
- 10-mmHg Transducer*: 0.00001 mmHg
- 1-mmHg Transducer**: 0.000001 mmHg (optional for expanded resolution)
Accuracy (Analysis System Only):
Includes nonlinearity, hysteresis, and nonrepeatability. Transducer manufacturer’s specifications.
- 1000-mmHg Range: within 0.15% of reading
- 10-mmHg Range*: within 0.15% of reading
- 1-mmHg Range**: within 0.12% of reading
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System Capacity:
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Sample Preparation: 2 degas ports
Analysis: 1 sample port
Up to 2 complete analysis units can be independently controlled by 1 computer
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Vacuum System:
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Degas: Either two-stage, mechanical vacuum pump, 5 x 10-3 mmHg ultimate vacuum or high vacuum system ultimate vacuum <10-8 mbar
Analysis: Multigas and Micropore: High vac system, ultimate <10-8 mbar
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Sample Temperature Control System:
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Temperature Range: 10 º above ambient to 1100 ºC
Rate Selection: Heat ramp rate controllable from 1 to 20 ºC per minute to 800 ºC, 10 ºC per minute to 1000 ºC per minute to 1100 ºC Temperature Selection: 1 ºC increments
Accuracy within ± 1 ºC. Stability within ± 1 ºC
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Degas System:
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Temperature Range: Ambient to 450 ºC(Programmable)
Temperature Selection: Digitally set, 1 ºC increments
Accuracy: Deviation less than +/- 10 ºC of set point at thermocouple
Backfill Gas: User-selectable, typically nitrogen or helium
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Sample Size:
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FlowThru sample tube stems are 1/2-in. (12.5-mm) OD with exhaust path for flow-through preparation. Standard FlowThru tubes are quartz for use up to 1100 °C |
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Electrical:
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Voltage: 100, 115, 230 VAC +/-10%
Frequency: 50/60 Hz
Power: 700 VA, operating (maximum)
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Physical:
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Height: 99 cm (39 in.)
Width: 85 cm (33.5 in.)
Depth: 61 cm (24 in.)
Weight: 115 kg (250 lbs)
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Miscellaneous:
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ISO 9001 manufacturer, CE certified |
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* High Vacuum Systems
** Micropore Systems
In keeping with a policy of ongoing product improvement, specifications are subject to change without notice
A Note About 32- and 64-Bit Windows and Micromeritics' Software
Micromeritics Windows based software is currently compatible with the 32-bit version of Microsoft Windows operating systems. However, the 64-bit versions of Microsoft Windows operating systems are not compatible with Micromeritics Windows based software. To avoid incompatibility issues Micromeritics Windows based software should be executed only within the 32-bit versions of Microsoft Windows operating systems.
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Since the 1960's Micromeritics has been modifying standard products and accessories to accommodate special needs. We have now expanded this service to include custom-designed analyzers and accessories.
Custom-Engineered Products
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