Highly porous NiO/poly(DVB)HIPE nanocomposites for asphaltene removal: synthesis, kinetics, and thermodynamic studies

Abstract

Asphaltene precipitation is one of the most important problems of the petroleum industry. Asphaltene collapses during petroleum processing and extraction from the well, blocking the pipes and causing many problems. For this reason, asphaltene should be removed from heavy crude oils to improve the quality of oil and prevent asphaltene deposition. In this study, for the first time, highly porous new polyHIPE nanocomposites containing NiO nanoparticles (NPs) have been prepared for asphaltene removal. The open-celled new poly(DVB)HIPE nanocomposites were synthesized by the polymerization of monomers in the external phase of water-in-oil emulsions containing NiO NPs in the organic phase. The highest surface area was obtained at 5 wt% of NiO NP loading (367 m2/g). The adsorption of asphaltenes from toluene solutions onto NiO/poly(DVB)HIPE nanocomposite was investigated in detail. Maximum adsorption was obtained as 384.6 mg/g at a temperature of 298 K for NiO/poly(DVB)HIPE nanocomposite. The Freundlich, Langmuir, and Temkin isotherm models were used to correlate the adsorption data of asphaltenes on NiO/poly(DVB)HIPE nanocomposite and adsorption constants of these models were calculated. The Freundlich and Langmuir gave better results at different temperatures. The pseudo-second-order kinetic model provided the best correlation with the experimental data (R2 ≥ 0.997). The results of the thermodynamic experiments showed that the adsorption was spontaneous and exothermic. It is concluded that the polyHIPE nanocomposites are important for the oil industry owing to having potential use as an adsorbent.