Stable Pickering emulsions comprising ZIF-8/MXene nanocomposites and chemical surfactant with effective H₂S scavenging performance

Hydrogen sulfide (H₂S) generation during oilfield operations presents significant safety, environmental, and operational challenges, necessitating effective in-situ scavenging solutions. In this context, Pickering emulsions stabilized by solid nanoparticles (NPs) at the oil–water interface offer a promising alternative to conventional systems by not only improving emulsion stability but also enabling multifunctional applications such as H₂S mitigation. Despite recent progress in emulsion and gas treatment technologies, emulsion formulations that are capable of effectively removing H₂S from sour gases are still lacking in the literature. Additionally, the integration of ZIF-8/MXene nanocomposites into Pickering emulsions for simultaneous stabilization and gas scavenging remains unexplored. Thus, this study aims to address this gap by designing a dual-functional Pickering emulsion system stabilized by ZIF-8/MXene nanocomposites in combination with Tween 40 surfactant, capable of both interfacial stabilization and H₂S removal. The nanocomposites were synthesized and characterized by XRD, SEM, and EDS. Oil-in-water (O/W) emulsions with varying concentrations (0.1–1.5 wt%) of the ZIF-8/MXene nanocomposites were systematically evaluated for rheological behavior, interfacial tension, kinetic stability, and structural integrity. Rheological analysis indicated a transition from Newtonian to shear-thinning behavior with increasing nanocomposite loading, suggesting the formation of internal networks. The emulsions maintained suitable flowability under elevated temperatures, and interfacial tension measurements showed significant reduction due to synergistic interactions between the nanocomposite and Tween 40. Stability assessments revealed minimal phase separation at lower nanocomposite concentrations, while higher loadings led to destabilization due to excess particle aggregation. H₂S removal experiments confirmed the system's scavenging functionality, with a breakthrough capacity of 1049.5 mg H₂S/L emulsion (76.54 mg H₂S/g nanocomposite). To the best of our knowledge, this is the first report on the formulation of ZIF-8/MXene-based Pickering emulsions and the demonstration of their excellent H₂S scavenging capability. The findings reported herein introduce a multifunctional platform that addresses both safety and operational challenges in oilfield applications.