Desorption Rate of Adsorbed Tritiated Water from Molecular Sieve 5A by Exchange with Environmental Water Vapor

Abstract

The desorption rate of tritiated water from molecular sieve adsorbed HTO, by exchange with the environmental water vapor, was measured. The molecular sieve, packed in a column, was initially changed with tritiated water and then humidified Ar gas was made to flow through it and the tritium concentration of effluent gas was measured. The desorption rate of tritiated water increased linearly with the water vapor pressure in the gas at constant flow rate. In the case where both the flow rate and the vapor pressure were kept constant, the amount of tritium left adsorbed on the molecular sieve decreased exponentially with time. It should be noted that the desorption rate was rather rapid even at room temperature and nearly all the tritiated water adsorbed on the molecular sieve was recovered by the flowing humidified gas at room temperature within several hours.

KEYWORDS:

• tritium
• HTO
• molecular sieves
• adsorption
• desorption
• exchange reaction rate
• humidified carrier gas
• vapor pressure
• tritium recovery