Kinetics of caffeine adsorption from aqueous solutions on active charcoal AC-0-9

Abstract

The process of the kinetics of caffeine adsorption from aqueous solutions on activated carbon AC-0-9, obtained from apple wood, was studied. Analysis of nitrogen adsorption-desorption isotherms demonstrated that this carbon adsorbent is basically mesoporous. The pseudo-two model describes best the kinetic process, lighlighting the role of functional groups on the activated carbon surface. The pseudo-one model only initially describes the kinetic process of caffeine adsorption on this activated carbon. It was found that the kinetics of the adsorption process of caffeine on AC-0-9 activated carbon takes place in two stages. In the first stage, the speed of intraparticle diffusion is high, due to the adsorption of caffeine molecules in macro and mesopores, and in the second stage, the speed of intraparticle diffusion is low, given the fact that adsorption occurs in micro- and supermicropores.