Chapter: Surface Area and Pore Structure by Gas Adsorption
The adsorption isotherm Adsorption theory and methods of extracting information from the adsorption isotherm Langmuir theory BET theory Standard isotherms, t- and alpha-plots Thickness equations Methods of characterization for microporous materials -- MP Procedure -- Dubinin-Radushkevich method -- Dubinin-Astakhov analysis -- Horvath-Kawazoe equation The cylindrical pore model extension of Saito and Foley The spherical pore model extension of Cheng and Yang The method of Cheng and Yang in regard to nonlinearity Methods of characterizing mesoporous and macroporous materials -- Kelvin equation -- BJH method Density functional theory Fitting model isotherms to experimental data by the method of deconvolution Surface energy distribution Rate of adsorption Measurement of the isotherm Application of gas laws Standard volume Nonideality Instrumental methods and theory of instrument design Static volumetric method -- Determining the manifold volume -- Determining the quantity of gas in the free space of the sample holder Warm free space Determining the quantity of gas at cryogenic temperature Cold free space -- Determining the quantity of gas adsorbed -- Control of cryogen level during tests -- Thermal transpiration Single sample volumetric analyzer The analysis gas manifold Software control of the dosing and pressure equilibration routines Dosing by pressure table Incremental dosing Fixed-quantity dosing Dose-sensitive data collection Equilibrium detection -- Making a test Saturation pressure measurement Free-space determination Determination of gas-adsorbed quantity The multiple-port volumetric analyzer The Gemini design The flowing-gas (dynamic) analyzer -- Design features -- Applying Dalton's law of partial pressures -- Calibration -- Making a test Recognition and avoidance of problems Leaks Instrument calibration Connecting an adsorptive gas supply to the instrument Sample preparation Helium entrapment Use of SealFrits and PrepSeals Selecting the appropriate adsorptive -- Krypton and argon vs. nitrogen for low surface area determinations -- Nitrogen vs. argon for micropore analyses Cryogen and adsorptive pairing Sample temperature Sample quantity -- Free-space values -- Thermal transpiration correction -- Equilibrium time -- Measured vs. entered saturation pressure Evaluation of results Inspection of the isotherm plot Evaluating the isotherm tabular data set Reduced data -- Physical parameters -- Guidelines and evaluation of data reduction methods -- BET C-value -- Data analyses by the BJH method A systematic approach to sample analyses by physical adsorption Sample preparation Analysis temperature Quantity of sample Surface area determination Porosity Symbols used in this chapter
Intellectual Property; all rights to all
intellectual property, copyright material,
trademarks (registered or not) remain with their respective owners.
from the adsorption isotherm