Biomimetic catalysis of ZIF-90@floating microspheres accelerates interface reactions in lipid degradation

The global challenge of oil pollution and its treatment necessitates innovative solutions. Lipases offer an efficient and environmentally friendly method for oil degradation. However, lipases are only active at the oil-water interface and their effectiveness is hindered by poor stability and inactivation. This study introduces ZIF-90 as an alternative to traditional lipases. It is capable of activating H₂O to generate •OH and •H radicals for hydrolysis of lipids, thereby demonstrating enzymatic activity comparable to lipases. Floating microspheres were developed to address the limitations of lipase stability and interface activation. These were created by 3D printing low-density hollow microspheres containing ZIF-90, ensuring the optimal positioning of all ZIF-90 at the oil-water interface during the reaction. This allows the ZIF-90 within the microspheres to fully interact with both the oil substrate and water molecules at the interface, effectively catalyzing the oil pollution degradation without stirring and emulsifying in large aquatic areas. This innovative approach results in catalytic activity 6.61 times higher than free enzyme. Notably, treatments involving strong acids or high temperatures promote the activation of coordination between the imidazole and Zn²⁺ of ZIF-90, significantly enhancing oil pollution degradation by 1.45 to 3.7 times. This research provides valuable insights and methodologies for developing novel biomimetic enzymes, with potential applications in enhancing the efficiency of other catalysts at the oil-water interface for addressing floating lipid pollution.