Promethium (Pm) in Water Treatment
Quick Answer
Promethium (Pm) is a lanthanide with atomic number 61. PubChem lists its standard state as solid and its relative atomic mass as 144.91276.
Promethium has no stable isotope and is not an ordinary rare-earth constituent in natural water. It is relevant chiefly to controlled nuclear or research materials; any real water case requires isotope-specific radiochemistry and radiological oversight, not a generic rare-earth treatment recipe.
Interesting Facts
- Promethium is named after Prometheus, the figure in Greek mythology who stole fire for humanity.
- It is the only lanthanide with no stable isotope; traces can arise from nuclear fission and rare natural nuclear processes.
- Chemical separation may follow other trivalent lanthanides, but radioactivity determines sampling, shielding and residual management.
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
Prometium (Pm)
1. Basic Information
| Atomic Number | 61 |
| Symbol | Pm |
| Atomic Weight | 145 (most stable isotope) |
| Category | Rare earth metals, lanthanides |
2. Physical and Chemical Properties
Prometium is a radioactive metal element that is very rarely found in nature. Some of its physical and chemical properties include:
- Solid form at room temperature
- Melting point: 1168°C
- Boiling point: 2460°C
- Density: 7.26 g/cm3
- General oxidation number: +3
- Prometium salts are pink or red in color
- Emits pale blue-green light
3. Presence in Water and Health Effects
Prometium is practically absent in natural water due to its rarity and radioactive nature. If exposed, prometium can accumulate on the surface of bones and is difficult to remove. Long-term health effects are not fully understood due to its rarity, but exposure to beta radiation from prometium decay can be harmful.
4. Water Treatment Applications and Removal Methods
Although rarely encountered in conventional water treatment, if prometium needs to be removed from water, some methods that may be effective are:
- Ion exchange using specialized cation exchange resins
- Reverse osmosis
- Chemical precipitation
- Adsorption using activated carbon or other specialized media
The order of prometium selectivity in cation exchange resins is as follows: Lu3+ < Yb3+ < … < Pm3+ < … < La3+
5. Industrial Use in Water Treatment
Prometium has no specific use in the water treatment industry due to its scarcity.
8. Environmental Impact and Sustainability Considerations
Prometium does not pose a significant environmental threat due to its rarity in nature. However, handling and disposal of artificially generated prometium must be done with care due to its radioactive nature. Sustainability considerations include:
- Safe management of radioactive waste
- Minimization of worker and environmental exposure
- Development of improved detection and monitoring methods