Enhancing CO ₂ Storage in Deep Saline Aquifers Using Nanoparticles: A Review

Increasing atmospheric CO2 concentrations are a principal contributor to anthropogenic climate change, necessitating robust and scalable carbon mitigation strategies. Deep saline aquifers are considered a highly suitable place for large-scale CO2 storage due to their substantial storage capacity and favorable geochemical environments. However, conventional CO2 storage approaches in deep saline aquifers, such as continuous CO2 injections, water alternating gas (WAG), and alternate aquifer injections, etc., still have limitations, including difficulties in ensuring long-term storage security, controlling CO2 migration in heterogeneous formations, and trapping efficiency. Therefore, this study examines the fundamental challenges associated with CO2 storage and provides a comprehensive assessment of how nanoparticle-based (NPs) strategies can enhance the overall efficacy of CO2 storage. The first part of this article investigates the impact of heterogeneity, geochemical interactions, aquifer properties, wettability, and impurities on the stability of CO2 in aquifers. Reported improvements indicate that using NPs enhances CO2 storage by improving dispersion, wettability, foam stability, absorption, and retention while reducing migration and breakthrough. Consequently, the final section of this review synthesizes previous studies on NPs, with a particular emphasis on commercial and byproduct NPs derived from sources such as rice husk, fly ash, and waste tires, etc. Furthermore, the environmental and economic ramifications of employing NPs to illustrate their importance in addressing global emissions issues are discussed. The key findings of this review demonstrate that nanoparticles can enhance long-term CO2 storage by improving CO2 injection efficiency, reducing CO2 leakage, and strengthening adsorption mechanisms, thereby providing a more effective pathway for climate change mitigation. Nonetheless, it is recommended that future research investigate their performance under complex reservoir conditions, including elevated temperatures, pressures, and salinities.