Zeolites

Crystalline, hydrated alkali-aluminium silicates with a porous, cage-like structure that gives them remarkable molecular-sieve, ion-exchange, and catalytic properties. They are useful as catalysts for the production of invert sugar and in many other chemical processes, and their uniform pores make them standard drying agents and adsorbents. In food-related applications they serve as carriers, anti-caking aids, and filtration media, and in packaging research they are explored for moisture and ethylene scavenging to extend produce shelf life. Their ion-exchange capacity is exploited in water softening and in the removal of unwanted ions. Food-grade zeolites must meet purity specifications, since natural deposits can contain fibrous contaminants.