Numerical Analysis of the Influence of Air Flow Rate on the Development of the Porous Structure of Activated Carbons Prepared from Macadamia Nut Shells

This paper presents the numerical analysis of the influence of air flow rate on the porous structure development of activated carbons prepared from macadamia nut shells. The analyses based on nitrogen and carbon dioxide isotherms were carried out by the new numerical clustering-based adsorption analysis method. Therefore, it was possible to evaluate the porous structure with high precision and reliability. In particular, the results obtained showed that activated carbon prepared at an air flow rate of 700 cm³/min has the highest adsorption capacity with respect to this adsorbate, but with surface heterogeneity. On the other hand, numerical analysis based on carbon dioxide adsorption isotherms showed that the activated carbon with the highest adsorption capacity towards carbon dioxide is the sample obtained at an air flow rate of 500 cm³/min. The analyses conducted have shown that too high an air flow rate causes a violent oxidation reaction, leading to uncontrolled burning of the carbonaceous substance and destruction of the structure of the smallest micropores.