PSD of Peach Stones Activated Carbons by the Heterogeneous Surface Mixed Model

D. A. SOARES MAIA.; J.C. ALEXANDRE DE OLIVEIRA; J. P. TOSO; K. SAPAG; RAÚL H. LÓPEZ; D.C.S. AZEVEDO

Granada

Simposio; The 10th International Symposium on the Characterization of Porous Solids (COPS-X); 2014

One of the key properties of activated carbons, directly related to its final application as an adsorbent, is the Pore Size Distribution (PSD). Any method for the determination of the PSD is based on the proposition of a model to represent the relevant geometric and structural characteristics of the porous material. It is important to stress the fact that such model is not intended to mimic the real porous structure, but it is rather an idealization intended to reproduce with a reasonable degree of accuracy the adsorptive properties of the material [1]. In this study, we have used a model that calculates the PSD taking into account the defects in the form of heterogeneous particles in the inner surface of each graphitic slit pore, called Heterogeneous Surface Mixed Model (HSMM) [2]. We particularly examined the effects of surface heterogeneity in the determination of the PSD for a controlled series of microporous carbons produced from peach stones as the precursor material, with different degrees of activation. The HSMM was used to obtain the PSDs of the samples based on Grand Canonical Monte Carlo (GCMC) simulated isotherms of N2 at 77K. It was found that our model is very flexible, allowing for the possibility to change the kind of heterogeneity of the particles and the coverage. The nice agreement between the simulated and experimental data is a positive step for further application of this model to study the adsorption process in other microporous solids.