Kinetics and thermodynamic studies of asphaltene adsorption onto Zeolite ZSM-5 nanoparticles

Asphaltene is one of the compounds in crude oil with the heaviest fraction, which causes it to settle and deposit on reservoir or extraction pipes. Various methods have been proposed for its severance or removal so far, as the adsorption of asphaltene using nanoparticles is one of the most efficient ones. The effects of parameters such as asphaltene concentration, temperature and the amount of adsorbent loaded (ZSM-5 zeolite) were investigated in order to optimize the adsorption process of asphaltenes. The physical and chemical properties of the adsorbents were also investigated by SEM, XRD and FTIR. SEM images showed that the ZSM-5 zeolite nanoparticles are highly efficient in adsorption of asphaltene and become agglomerated after adsorption. XRD and FT-IR analyzes also confirmed the presence of asphaltene in the ZSM-5 zeolite after the adsorption process. The equilibrium data were fitted with the Langmuir and Freundlich isotherms to know the adsorption isotherm. The results showed that the adsorption behavior of asphaltene on ZSM-5 zeolite can be well described using Langmuir isotherm. The kinetic results showed that the asphaltenes were rapidly adsorbed to the zeolite in less than 2 hours. By comparing the pseudo-first-order and pseudo-second-order kinetic models, it can be concluded that the pseudo-second-order kinetic model well predicts the kinetic behavior of asphaltene adsorption on ZSM-5 zeolite nanoparticles.