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. The analyses of nitrogen adsorption-desorption isotherms demonstrated that this carbon adsorbent is basically mesoporous. The pseudo-two model describes best the kinetic process, highlighting 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 takes place in micro- and supermicropores.

Keywords

• adsorption kinetics
• activated carbon
• caffeine