Krypton (Kr) in Water Treatment

Quick Answer

Krypton (Kr) is a noble gas with atomic number 36. PubChem lists its standard state as gas and its relative atomic mass as 83.80.

Krypton is not normally a treatment target in water. If a dissolved noble gas must be controlled in a specialized process, gas-transfer operations such as aeration, vacuum degassing or membrane contactors are more relevant than particle filters.

Interesting Facts

• Krypton was discovered in the residue left after nearly all other components of liquid air had boiled away; its name comes from the Greek for “hidden.”
• Stable krypton is chemically inert, while radioactive krypton-85 is a specialised tracer and nuclear-monitoring concern.
• Because dissolved krypton is a gas rather than a particle or ordinary ion, gas transfer—not a sediment filter—is the relevant separation principle.

Water-treatment Design Implications

An element name alone is not enough to select treatment equipment. Confirm chemical form or speciation, total and dissolved concentration, pH, alkalinity, competing ions and the product-water target. Send the water-analysis results to Watermart to identify additional testing and shortlist processes before equipment is specified.

Summary Data Sources

• PubChem — Krypton
• IUPAC Periodic Table of Elements
• WHO chemical hazards in drinking-water

Krypton (Kr)

1. Basic Information

Atomic Number	36
Symbol	Kr
Atomic weight	83.80 g/mol
Category	Noble gas

2. Physical and Chemical Properties

Krypton is a colorless, odorless, and non-reactive noble gas. It has a melting point of -157°C and a boiling point of -153°C. Its density is about 3.73 g/L at 20°C. Krypton is very difficult to react chemically due to its stable electron structure, but can form some compounds such as krypton difluoride (KrF2) under certain conditions.

3. Presence in Water and Health Effects

Krypton is rarely found in natural water due to its inert nature and very low solubility. Its concentration in air is about 1 ppm. Krypton does not cause significant health effects in normal concentrations. However, in high concentrations it can cause asphyxia as it displaces oxygen.

4. Water Treatment Applications and Removal Methods

Since krypton is rarely present in water and is inert, its removal from water is rarely necessary. However, if required, some methods that may be used include:

• Gas stripping: Uses a gas stream to remove dissolved gases from water
• Membrane degassing: Using a hydrophobic membrane to separate gas from water

5. Industrial Use in Water Treatment

Krypton has no direct application in industrial water treatment. However, the radioactive isotope krypton-85 is sometimes used to detect leaks in closed pipe systems or sealed containers that may contain water or other liquids.

8. Environmental Impacts and Sustainability Considerations

Stable natural krypton is not a meaningful water pollutant. Krypton-85 releases are a specialised nuclear-monitoring issue; they should be discussed using measured activity and applicable radiological controls, without extrapolating unsupported weather or health claims.