Oxygen Scavenging Hybrid Nanostructure: Localization of Different Iron Nanoparticles on Montmorillonite Clays Host

According to the great potential of zero-valent iron nanoparticle applications in the environmental, medical, chemical, packaging and many other industries, there is still a need to tailor their production methods. This study reports the production of a hybrid nanostructure based on iron nanoparticles (INPs) produced in/on montmorillonite (MMT) nanoclays as an oxygen scavenger and barrier additive in polymeric packaging materials of oxygen-sensitive products. INPs and MMT were demonstrated to have effective mutual interactions in which the MMT host played a chemophysical trapping role for iron particles, causing smaller particles around 10 nm with 6.2 g/m² higher specific surface area by limiting particle growth and agglomeration. In return, the embedding of primary iron cations in/on clays and growth of these particles during the reduction reaction pushed the clay layers out and helped further clay intercalation-exfoliation. Effective study of solvent and primary cation (Fe²⁺/Fe³⁺) types showed different preferences in interacting with natural and alkylammonium-modified MMT, resulting in the different site selection. Fe²⁺ cations preferred to migrate to the interlayer space, whereas Fe³⁺ cations tended to bond to the clay surface. The obtained results in this study suggest tailoring the ultimate oxygen scavenging capacity, shelf life, and migration properties of a hybrid nanoparticle according to the application requirements.