Enhanced stability and H₂S scavenging performance of ZIF-8 nanoparticle-based Pickering emulsions

H₂S is a toxic and corrosive gas frequently encountered in oil and gas operations, necessitating effective removal strategies for safety and sustainability. While nanoemulsions have been explored, the development of Pickering emulsions with intrinsic H₂S scavenging capability remains largely unexamined. This study investigates diesel-in-water Pickering emulsions stabilized by ZIF-8 nanoparticles and Tween 40 surfactant, addressing both emulsion stability and H₂S mitigation. Pickering emulsions were prepared with ZIF-8 (0.1–1.5 wt%), Tween 40 (0.5 wt%), and antifoam (0.15 wt%) and evaluated using zeta potential, droplet size distribution, dynamic interfacial tension (IFT), and microscopy. Stability tests revealed that emulsions with lower ZIF-8 concentrations (0.1 and 0.5 wt%) exhibited enhanced stability, with minimal phase separation (22–28 %) over 50 days. Increasing Tween 40 content further improved stability, preventing demulsification for up to five months. H₂S scavenging tests showed that emulsions stabilized by 1.5 wt% ZIF-8 achieved a breakthrough capacity of 2598 mg/L and a scavenging efficiency of 189.5 g/kg, outperforming conventional scavengers. These findings highlight the dual functionality of ZIF-8 as both an emulsion stabilizer and an H₂S scavenger. To the best of our knowledge, this study represents the first application of ZIF-8-stabilized Pickering emulsions for simultaneous emulsion stabilization and H₂S mitigation.