Effect of Carbon Dioxide upon Partition Equilibrium of Iodine between Air and Aqueous Sodium Hydroxide Solutions

摘要

The effect of the presence of carbon dioxide on the partition equilibrium of iodine between air and aqueous sodium hydroxide solutions was investigated using a semiflow-and a batch-type experimental apparatus. The concentrations of all measurable chemical species were measured. The overall partition coefficient of iodine decreased significantly with the increase in the concentration of carbon dioxide in the gaseous phase. The concentration distributions of the participating iodine species in the aqueous phase varied significantly with the variation in the concentration of carbon dioxide. It was found that these experimental results are explained by considering the chemical reactions participated in the partition equilibrium and that the concentration dependency of overall partition coefficient is clarified with use of an approximate theoretical analysis.