ZSM-5/Fe3O4 and ZSM-5/Fibrous Cellulose as Two Durable and Recyclable Adsorbents for Efficient Removal of Asphaltenes from Crude Oil

Asphaltenes are one of the heaviest fractions of crude oil, which causes it to settle and deposit into the reservoir rock or extraction and transfer pipes. So far, various methods have been proposed to separate or remove asphaltenes, and among them, the adsorption of asphaltenes using nanoparticles is one of the most efficient method. In this way, two strong, durable, and recyclable adsorbents towards adsorption of asphaltenes from crude oil were synthesized by incorporation of Fe3O4 and fibrous silica (KCC-1) nanoparticles (NPs) into ZSM-5 zeolite nanocrystals. Structural, physical and surface characteristic properties of the adsorbents were studied by FTIR, XRD, VSM, BET, FE-SEM, and TEM analyses. In order to optimize the asphaltenes adsorption process, the effect of some parameters such as asphaltenes concentration, temperature and the amounts of adsorbents was studied. The asphaltenes adsorption isotherms were suitably correlated to the Langmuir model for ZSM-5/Fe3O4 as well as ZSM-5/KCC-1 nanoparticles, which suggests the monolayer adsorption of asphaltenes onto the nanoparticles through a self-association as assumed in the literature. Kinetic results showed that asphaltenes is rapidly adsorbed by the nanoparticles within about 2 h. By comparing the quasi-first-order and quasi-second-order kinetic models, it was found that the quasi-second-order kinetic model well predicts the adsorption kinetic of the asphaltenes on each of the ZSM-5/Fe3O4 and ZSM-5/ KCC-1 nanoparticles.