Characterization of porous solids using integrated nitrogen sorption and mercury porosimetry

Sean P Rigby, Robin S Fletcher, Sandra N Riley

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

The two different techniques of nitrogen sorption and mercury porosimetry, which are generally utilized completely sep., have been integrated into the same expt. to improve upon the information obtained from both methods. Nitrogen sorption isotherms have been run both before and after a mercury porosimetry expt. on the same sample. This expt. has revealed that for a particular type of sol-gel silica catalyst support the entrapped mercury is confined to only the very largest pores in the material. Light micrograph studies have shown that the spatial distribution of entrapped mercury is highly heterogeneous. These results suggest that mercury entrapment within the material is caused by a mechanism involving macroscopic (>0.1 mm) heterogeneities in the pore structure. These findings conflict with the usual assumptions generally made in simulations of porosimetry based on random pore bond network models. The new work has shown that, in conjunction with computer simulations involving the correct mercury retraction mechanism, mercury porosimetry and nitrogen sorption can be used to study the spatial distribution of all pore sizes within a mesoporous material. A percolation anal. of the nitrogen sorption data, obtained both before and after mercury entrapment, allowed broad features of the spatial disposition of variously sized pores to be detd. The results reported here also support the use of new, semi-empirical alternatives to the Washburn Equation to analyze raw mercury porosimetry data, rather than the traditional approach. [on SciFinder (R)]
Original languageEnglish
Pages (from-to)41-51
Number of pages11
JournalChemical Engineering Science
Volume59
Issue number1
Publication statusPublished - 2004

Keywords

  • effect of pore heterogeneity of porous silica on its property)
  • Adsorption (isotherm
  • Pore (mercury
  • porous solid silica heterogeneity nitrogen sorption mercury porosimetry
  • Pore size
  • Apparatus (characterization of porous silica solid using integrated nitrogen sorption and mercury porosimetry)
  • Heterogeneity (pore
  • Pore size distribution (of porous silica solid characterized using integrated nitrogen sorption and mercury porosimetry)
  • characterization of porous silica solid using integrated nitrogen sorption and mercury porosimetry)
  • nitrogen

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