Small-angle X-ray scattering studies of adsorption in Vycor glass.
Porous Vycor is examined by measuring CH(2)Br(2) adsorption in situ with small-angle X-ray scattering. When a class of pores fills with condensed vapors of this particular adsorbate it ceases to act as scatterer and only the remaining empty pores produce a measurable intensity. By determining a number of scattering curves at various relative pressure loadings details on the structure of the glass as well as on the adsorption/desorption mechanism are obtained. Pore chord length and specific surface area are estimated from Porod tangent analysis to 78 A and 108 m(2)/g. Comparison of the results with those reported for N(2) and Ar adsorption is also given. The role of network effects on the shape of the hysteresis loop is considered and the pore-blocking hypothesis is verified from the scattering spectra. The pore connectivity is calculated to 5.6. The X-ray data are further treated with the inverse Fourier transformation technique. Pore-size distributions are extracted and weighed against the prediction of the Kelvin equation.
Mitropoulos
A Ch
ACh
Department of Petroleum Technology, Cavala Institute of Technology, 65 404 St. Lucas, Cavala, Greece. amitrop@teikav.edu.gr
D000327:Adsorption; D015946:Ethylene Dibromide / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D016062:Porosity; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction / Q000379:methods*
D015946:Ethylene Dibromide