Surface modification of nanoparticles to improve oil recovery Mechanisms: A critical review of the methods, influencing Parameters, advances and prospects

[Display omitted] •Surface modification of NPs can be classified as in-situ or post-synthesis. Both employ identical procedures.•Grafting-from increases grafting densities and polymer coverage of the NP surface than grafting-to.•Surface modifications can reduce particle hydrophilicity and thus particle retention on the rock surface.•In order to guide future research in this field, leading surface modification methods must be described in detail. The utilization of nanoparticles (NPs) in enhanced oil recovery (EOR) has a lot of benefits however, the usage of bare NPs still has a few drawbacks, including instability, agglomeration and aggregation, which can cause pore channel obstruction and quick sedimentation resulting in low oil recovery. Nonetheless, surface modification of NPs can circumvent these problems however, an account of leading approaches for surface modification and their effect on improving EOR effectiveness interconnected with NPs microscopic features, with the aim of providing a guide for future efforts in this area is essential. Here, a critical review on surface modification of NPs to improve oil recovery mechanisms is presented. Surface modification of NPs can be classified into two categories: in-situ surface modification and post-synthesis surface modification, both of which involve grafting, coupling, surfactant usage, and esterification to achieve the same results. Surface modifications can reduce particle hydrophilicity, reducing particle retention on rock surfaces. Depending on the NPs' surface nature, many techniques based on surface affinity for different chemical groups have been created. The study equally revealed that functionalized NPs have excellent mobility regulation, thermal stability and rheological properties, and they make oil droplets stable against coalescence. Moreover, the application of different surfaced modified NPs in EOR were reviewed. Finally, the challenges encountered were identified with proffered solutions, future trend and research opportunities were outlined. Since each modification type is tailored to the final application, there is no single best NPs surface modification technique. As a result, when it comes to specific goals, all techniques are equally weighted.