Adsorption kinetics and catalytic oxidation of asphaltene on synthesized maghemite nanoparticles

• Maghemite nanoparticles were synthesized using a facile and cheap method.
• The synthesized maghemite nanoparticles were used to adsorb asphaltene.
• Adsorption kinetics and isotherm of asphaltene were studied.
• The results were analyzed using TEM, XRD, TGA and DTA analyses.
• Catalytic effect of maghemite on asphaltene oxidation was demonstrated.

ObjectiveThe purpose of this article is to assess adsorption kinetics and catalytic oxidation of asphaltene onto synthesized maghemite (γ-Fe2O3) nanoparticles.MethodsTo synthesize the maghemite nanoparticles (MNPs), the co-precipitation of ferric and ferrous ions method was used as a facile and cheap method. Morphology, crystalline and chemical structure of the synthesized MNPs were investigated by transmission electron microscope (TEM) and X-ray diffraction (XRD) analyses. The Lagergren pseudo-first- and second-order models were applied for determination of adsorption kinetics and its mechanism. Furthermore, thermogravimetry analysis (TGA) of both pure asphaltene and asphaltene–maghemite (MNPs with adsorbed asphaltene, MNP/Asph) was carried out.ResultsThe results of XRD and TEM analyses showed that the γ-Fe2O3 nanoparticles are crystalline and roughly spherical in shape with about 10 nm in size. It was found that the experimental kinetic data are in good agreement with the pseudo-second-order model; moreover, the Langmuir isotherm model fits well the adsorption data. Furthermore, TGA results showed that the onset temperature of asphaltene oxidation and temperature of the maximum rate of oxidation decrease by ~203 °C and ~123 °C, respectively. The same results were also obtained through analyzing heat flow curves of differential thermal analysis (DTA).ConclusionMaghemite nanoparticles (MNPs) were synthesized using an easy and low-cost method. Asphaltene adsorption kinetics on MNPs followed the pseudo-second-order Lagergren model. TGA and DTA analyses demonstrated the drastic catalytic effect of the MNPs.Practice/implicationsThe synthesized MNPs were used for the adsorption of asphaltene. Study on asphaltene adsorption kinetics and the catalytic effect of MNP on asphaltene is a very useful attempt in the control or elimination of asphaltene deposition in the petroleum industry.

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