Topology-Dependent Antiviral Activity of H-Form Zeolites: Discovery of a Highly Active Natural Mordenite.

The global threat of viral infections highlights the urgent need for the development of effective antiviral solid materials. Proton-form zeolites have been recently reported to inactivate viruses such as influenza and M13 bacteriophage without relying on metal ion exchange, suggesting a promising approach for low-cost and nondiscoloring antiviral applications. However, these findings have so far been confined primarily to FAU-type zeolites, leaving the relationship between antiviral activity and the physicochemical properties of zeolites─such as framework topology and chemical composition─largely unexplored. Here, we conducted antiviral assays using both synthetic and natural zeolites against M13 bacteriophage as a model virus, aiming to establish design principles for metal-free antiviral zeolites. Natural mordenite (MOR-type) zeolites exhibited significantly higher antiviral activity than commercially available synthetic zeolites, underscoring their potential as environmentally benign and cost-effective antiviral materials. Among the synthetic H-form zeolites investigated in this study, MOR with a Si/Al ratio of 9.0 showed outstanding antiviral activity. Comprehensive characterization revealed a strong correlation between surface acid strength and antiviral performance, suggesting that the superior activity of MOR-type zeolites arises from their high intrinsic acidity associated with their framework structures.