Effect of the pore geometry in activated carbon characterization

J.P.TOSO; R.H. LÓPEZ; D.A. SOARES MAIA; J.C.A DE OLIVEIRA; V. CORNETTE; M. LUCENA; C.L. CALVALCANTE; D.C.S ACEVEDO

Simposio; Eighth International Symposium Effects of Surface Heterogeneity in Adsorption and Catalysis on Solids ISSHAC-8; 2012

The characterization  of activated carbons (AC) by using the independent pores model, with special emphasis on the question  of how the pore geometry can affect the resulting Pore Size Distribution (rPSD) is discussed. Using the alternative Mixed Geometry Model (MGM)[2] a virtual solid was built (representing  the ?experimental sample?). The model use a monopore adsorption isotherms kernel generated by  GCMC to different pore size and for two pore geometry: slit and triangular. The adsorption isotherms of a virtual MGM solids corresponding to a source Pore Size Distributions (sPSDs) whit different pore volume ratios slit/trian. Then are fitting with the traditional Slit Geometry Model (SGM) and the results analyzes. Finally it is shown experimental results obtained for two different groups of AC samples. For the first group, the MGM significantly improved the experimental isotherms fit over the SGM, coinciding with a MGM high triangular pore volume. For the other group, the fits were similar for both models, coinciding with near zero MGM triangular volume pore , and also resulting in virtually identical SGM rPSD and  MGM (slit) rPSD.  In conclusion, it appears that the recent MGM may be an acceptable extension of the traditional SGM.