(725h) High Yield Synthesis of ZIF-8 Nanoparticles Using Stoichiometric Reactants in a Jet-Mixing Reactor
Nanomaterials are increasingly important for many fields such as Zeolitic Imidazolate Frameworks for use in membrane and adsorption applications. A significant challenge for greater utilization of ZIFs is creating a continuous synthesis method to produce these materials with uniform, nanometer-scale particle size, and high surface areas while achieving high yields. Current continuous methods tend to produce low yields, particles larger than 100 nm, and/or low quality materials. We demonstrate a novel method to produce ZIF-8 nanoparticles with uniform diameters in the range of 60-80 nm involving a jet-mixing reactor. While many ZIF nanoparticle syntheses utilize excess ligand, the jet-mixing reactor can be operated at ambient conditions using preferred solvents and stoichiometric quantities of ligand and metal (i.e., ligand:metal of 2:1) to synthesize ZIF-8 with yields as high as 89%. The improved yield can be attributed to the homogeneous conditions created in the reaction volume as a result of the turbulent mixing generated by the high velocity flow through the jets. The jet-mixing reactor is studied to determine the effect of different synthesis parameters including ligand to metal ratio, base concentration, solvent, and mixing intensity. The particle properties including the size, morphology, and yield are affected most strongly by the base concentration. Further, we demonstrate that the jet-mixing method can be scaled to increase productivity by designing, constructing, and testing a larger reactor.