Asphaltene adsorption of Co₃O₄ nanoparticles modified by SiO₂ film

Asphaltene precipitation could have several negative consequences, including production decline, wellbore plugging, and even severe safety concerns. Therefore, an effective strategy of asphaltene adsorption is highly significant. Nanoparticles possess a large surface area, showing a high adsorption potential for asphaltene. However, the self-aggregation property limits its adsorption capacity. In this work, the Co₃O₄ nanoparticles were ingeniously selected as an inhibitor of asphaltene precipitation, and a porous SiO₂ film was formed via the sol-gel method. The evaluation experiments indicated that the SiO₂ film significantly reduced the self-aggregation. Hence, the specific surface area of nanoparticles increased from 20.87 m²/g to 29.25 m²/g. Meanwhile, molecular dynamics simulations confirmed that the modified nanoparticles exhibited 1.6 times higher adsorption energy and a lower mean square displacement than the fundamental nanoparticles. With these improvements, the Co₃O₄-SiO₂ nanoparticles developed greater stability and dispersion, which raised the adsorption of the nanoparticles on asphaltene from 1.24 mg/m² to 1.53 mg/m², presenting a considerable adsorption capacity. This study broadens the selection of nanoparticles for asphaltene adsorption. It demonstrates the improvement of nanoparticles by porous SiO₂ film in various aspects, which can provide a solution for inhibiting asphaltene precipitation in oil fields as well as guidance for subsequent functionalization of nanoparticles.