Removal of dissolved 85Kr by vacuum degassing method

Area of Science:

• Radiochemistry
• Chemical Engineering
• Environmental Science

Background:

• Unsealed radioactive 85Kr gas is used as an internal radiation source in liquid-phase chemical reactions.
• Efficient removal of dissolved 85Kr from liquid reactants post-irradiation is essential for safety and process control.

Purpose of the Study:

• To investigate the effectiveness of vacuum degassing for removing dissolved 85Kr from a liquid reactant.
• To determine the influence of key parameters such as temperature, initial concentration, and stirring on the degassing efficiency.

Main Methods:

• Experiments were conducted using 500 ml of water as the liquid reactant with dissolved 85Kr.
• Vacuum degassing was employed, with variations in temperature, initial 85Kr concentration, and solution stirring.

Main Results:

• The removal efficiency of dissolved 85Kr significantly increased with higher degassing temperatures.
• Dissolved 85Kr concentration decreased exponentially with the reciprocal of degassing temperature.
• Solution stirring markedly enhanced the removal effect, while initial 85Kr concentration had no independent impact.
• A removal factor of 5 x 10^3 for dissolved 85Kr was achieved at 33 degrees C after 30 minutes.

Conclusions:

• Vacuum degassing is a viable method for removing dissolved 85Kr from liquid reactants.
• Optimizing degassing temperature and employing solution stirring are critical for maximizing removal efficiency.
• The method's independence from initial 85Kr concentration suggests broad applicability.