Desikants

Desikants, more commonly spelled desiccants, are substances that induce dryness by absorbing or adsorbing water vapor from the surrounding air. They are used to protect moisture-sensitive goods during storage and transport and are typically placed in small porous sachets or canisters inside packaging, containers, or storage environments.

The most common desiccants include silica gel, calcium chloride, molecular sieves (zeolites), and natural clay desiccants. Silica gel is widely used in consumer packaging due to its stability and high surface area. Calcium chloride is highly hygroscopic and effective in damp conditions but can liquefy as it becomes saturated. Molecular sieves offer precise humidity control and are favored in pharmaceuticals and electronics for stringent dryness. Clay desiccants are a low-cost option for general purposes. Some desiccants are indicating types that change color when saturated, signaling replacement; newer indicators aim to avoid toxic elements.

Desicants are employed in a variety of settings, including food and beverage packaging, electronics and battery housings, pharmaceuticals, archival and art storage, and leather or wood goods. They can be designed as single-use packs or as reusable systems. Reusable desiccants are typically regenerated by heating or vacuum drying to remove absorbed water; single-use variants are replaced after saturation.

Safety and handling considerations vary by material. Silica gel is generally inert and safe when used as intended, but ingestion should be avoided. Calcium chloride can be corrosive to skin and eyes and may cause irritation if mishandled. Some indicating desiccants use toxic indicators, though safer alternatives are increasingly common. Proper disposal and adherence to product guidelines are advised.