volatilization

Volatilization is the process by which a substance transitions from a condensed phase (solid or liquid) into a vapor. It includes evaporation, boiling, and sublimation and is governed by the substance's volatility, environmental conditions, and phase state.

In liquids, volatilization typically refers to evaporation, a surface process in which molecules escape into the gas phase at temperatures below the liquid's boiling point. The rate depends on vapor pressure, temperature, surface area, air flow, humidity, and the presence of other solvents or solutes that may alter volatility.

In solids, volatilization can occur by sublimation, where a solid converts directly to gas without passing through a liquid phase. Substances with appreciable vapor pressures at ambient or elevated temperatures can sublime under appropriate conditions.

Volatilization is an important pathway for the fate of chemicals in the environment and in industrial processes. In agriculture, ammonia and some pesticides can volatilize from soil or plant surfaces, leading to air emissions and reduced input efficiency. In manufacturing, solvents and additives may volatilize during drying, coating, or distillation, enabling recovery or requiring emission controls. In geochemistry and volcanology, volatilization accompanies degassing of magmas and the transport of volatile species.

Factors controlling volatilization include temperature and pressure, vapor pressure (or Henry's law constant), particle or surface area, mixing or wind speed, humidity, and chemical interactions with surrounding media. Volatilization rates can be estimated with mass-transfer models and constants that relate temperature and vapor pressure to flux.

Overall, volatilization describes a broad set of phase-change processes that transfer material from a condensed phase into the gas phase, affecting environmental fate, process design, and industrial safety.