Asphaltene adsorption on reservoir rock minerals causes wettability alteration and pore plugging which subsequently reduces crude oil production. Also, it has a negative effect on the efficiency of production and enhanced oil recovery operations. In this study, the adsorption of extracted asphaltenes of two samples of Iranian oil fields on dolomite, quartz, and magnetite was investigated in two- and three-phase systems in both static and dynamic flow modes. Mineral adsorbents were analyzed by Brunauer-Emmett-Teller and X-ray fluorescence methods. Also, several laboratory tests including elemental analysis, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy were carried out to characterize asphaltenes. The results showed that in addition to the effect of known parameters such as asphaltenes concentration and specific surface area of the solid phase, the water phase also affects the amount of asphaltenes adsorption. The adsorption amount of asphaltenes increases with increasing the specific surface area of adsorbent (decreasing particle size) and increasing the initial concentration of asphaltenes, and decreases with the addition of water to the two-phase system. The static adsorption amount of asphaltenes in a two-phase system can be up to 90% higher than the adsorption amount in a three-phase system. Doubling the fluid flow rate in dynamic adsorption significantly (by about 20%) reduces the asphaltenes adsorption, which could be a sign of physical adsorption of asphaltenes on adsorbents. The structure and elemental composition of asphaltenes also have a significant effect on asphaltenes adsorption. The asphaltene sample, which had a more aromatic nature and high nitrogen content, had higher adsorption on reservoir rock minerals. Finally, fitting the adsorption equilibrium models with experimental data reveals that the adsorption isotherm model depends on the type and particle size of the adsorbents and the concentration and type of asphaltenes.

Oil spills are a global concern by virtue of their distractive effects on the ecosystem. Many studies have examined the use of porous materials as sorbents for contaminants from different polluted waters. For example, hydrophobic metal organic frameworks, especially zeolitic imidazolate frameworks (ZIFs) with high porosity, have attracted lots of attention. ZIFs are a subclass of metal organic frameworks and display an excellent performance toward oil/water separation compared with other porous materials. Nevertheless, the performance of ZIFs toward oil spills cleanup has not been reviewed. Accordingly, this article overviews the different methods for ZIF preparation, their corresponding structure, and their various applications as sorbents and in particular, recent developments in cleaning up oil spills with meso and micro-porous ZIFs. The investigation of the literatures revealed that the effective parameters on the performance of porous ZIFs are specific surface area, pore diameters of ZIF, and the size of cavities due to interconnecting of ZIF particles. The ZIF-8 with a high surface area of 1408 m ${}^2$/g and 1384.2 m ${}^2$/g and adsorption capacity up to 3000 mg/g was studied more than the other ZIF structures. Models predications revealed the maximum adsorption capacity of 6633 mg/g for ZIF-8. Recently, investigations focused on carbonitride foam and melamine sponge as templates of ZIF powder. In comparison with synthesis methods, dip coating as a facial synthesis method was introduced for production and anchoring ZIF particles on the substrate. The recyclability of crude oil and the reusability of the ZIF sorbents are highlighted. Moreover, this article reviews recent developments of ZIFs synthesis, current challenges, and prospects for the use of ZIFs in oil/water separation. The findings of this study can help to better understand widespread applications of ZIFs, effective features of a sorbent, and methods to improve adsorption capacity. As cleaning up oil spills is known as an important issue, this is the first study on ZIFs in particular oil/water separation which provides a summary of researches in a simple form along with recent developments compared to published reviews.