Powder Surface Area and Porosity

ISBN-13: 9789401089531 / Angielski / Miękka / 2011 / 234 str.

S. Lowell

Opis

feed rate 9 gravitational constant G Gibbs free energy GS free surface energy h heat of immersion per unit area; specific reaction rate K Harkins-Jura constant I length L heat of liquefaction M mass M molecular weight n number of moles N number of molecules;

Spis treści

I Theoretical.- 1 Introduction.- 1.1 Real surfaces.- 1.2 Factors affecting surface area.- 1.3 Surface area from size distributions.- 2 Gas adsorption.- 2.1 Introduction.- 2.2 Physical and chemical adsorption.- 2.3 Physical adsorption forces.- 3 Adsorption isotherms.- 4 Langmuir and BET theories.- 4.1 The Langmuir isotherm, type I.- 4.2 The Brunauer, Emmett and Teller (BET) theory.- 4.3 Surface areas from the BET equation.- 4.4 The meaning of monolayer coverage.- 4.5 The BET constant and site occupancy.- 4.6 Applicability of the BET theory.- 4.7 Some criticism of the BET theory.- 5 The single point BET method.- 5.1 Derivation of the single-point method.- 5.2 Comparison of the single-point and multipoint methods.- 5.3 Further comparisons of the multi- and single-point methods.- 6 Adsorbate cross-sectional areas.- 6.1 Cross-sectional areas from the liquid molar volume.- 6.2 Nitrogen as the standard adsorbate.- 6.3 Some adsorbate cross-sectional areas.- 7 Other surface area methods.- 7.1 Harkins and Jura relative method.- 7.2 Harkins and Jura absolute method.- 7.3 Permeametry.- 8 Pore analysis by adsorption.- 8.1 The Kelvin equation.- 8.2 Adsorption hysteresis.- 8.3 Types of hysteresis.- 8.4 Total pore volume.- 8.5 Pore-size distributions.- 8.6 Modelless pore-size analysis.- 8.7 V?t curves.- 9 Microporosity.- 9.1 Introduction.- 9.2 Langmuir plots for microporous surface area.- 9.3 Extensions of Polanyi’s theory for micropore volume and area.- 9.4 The t-method.- 9.5 The MP method.- 9.6 Total micropore volume and surface area.- 10 Theory of wetting and capillarity for mercury porosimetry.- 10.1 Introduction.- 10.2 Young and Laplace equation.- 10.3 Wetting or contact angles.- 10.4 Capillarity.- 10.5 Washburn equation.- 11 Interpretation of mercury porosimetry data.- 11.1 Application of the Washburn equation.- 11.2 Intrusion—extrusion curves.- 11.3 Common features of porosimetry curves.- 11.4 Solid compressibility.- 11.5 Surface area from intrusion curves.- 11.6 Pore-size distribution.- 11.7 Volume In radius distribution function.- 11.8 Pore surface area distribution.- 11.9 Pore length distribution.- 11.10 Pore population.- 11.11 Plots of porosimetry functions.- 11.12 Comparisons of porosimetry and gas adsorption.- 12 Hysteresis, entrapment, and contact angle.- 12.1 Introduction.- 12.2 Contact angle changes.- 12.3 Porosimetric work.- 12.4 Theory of porosimetry hysteresis.- 12.5 Pore potential.- 12.6 Other hysteresis theories.- 12.7 Equivalency of mercury porosimetry and gas adsorption.- II Experimental.- 13 Adsorption measurements-Preliminaries.- 13.1 Reference standards.- 13.2 Other preliminary precautions.- 13.3 Representative samples.- 13.4 Sample conditioning.- 14 Vacuum volumetric measurements.- 14.1 Nitrogen adsorption.- 14.2 Deviation from ideality.- 14.3 Sample cells.- 14.4 Evacuation and outgassing.- 14.5 Temperature control.- 14.6 Isotherms.- 14.7 Low surface areas.- 14.8 Saturated vapor pressure, P0 of nitrogen.- 15 Dynamic methods.- 15.1 Influence of helium.- 15.2 Nelson and Eggertsen continuous flow method.- 15.3 Carrier gas and detector sensitivity.- 15.4 Design parameters for continuous flow apparatus.- 15.5 Signals and signal calibration.- 15.6 Adsorption and desorption isotherms by continuous flow.- 15.7 Low surface area measurements.- 15.8 Data reduction-continuous flow.- 15.9 Single-point method.- 16 Other flow methods.- 16.1 Pressure jump method.- 16.2 Continuous isotherms.- 16.3 Frontal analysis.- 17 Gravimetric method.- 17.1 Electronic microbalances.- 17.2 Buoyancy corrections.- 17.3 Thermal transpiration.- 17.4 Other gravimetric methods.- 18 Comparison of experimental adsorption methods.- 19 Chemisorption.- 19.1 Introduction.- 19.2 Chemisorption equilibrium and kinetics.- 19.3 Chemisorption isotherms.- 19.4 Surface titrations.- 20 Mercury porosimetry.- 20.1 Introduction.- 20.2 Pressure generators.- 20.3 Dilatometer.- 20.4 Continuous-scan porosimetry.- 20.5 Logarithmic signals from continuous—scan porosimetry.- 20.6 Low pressure intrusion-extrusion scans.- 20.7 Scanning porosimetry data reduction.- 20.8 Contact angle for mercury porosimetry.- 21 Density measurement.- 21.1 True density.- 21.2 Apparent density.- 21.3 Bulk density.- 21.4 Tap density.- 21.5 Effective density.- 21.6 Density by mercury porosimetry.- References.