Tritium separation from radioactive wastewater by hydrogen isotope‒selective exchange of hydrogen‒bonded fluorine (2023)

Hyojoo Kim, Bhupendra Kumar Singh, Wooyong Um

Journal of Industrial and Engineering Chemistry, Volume 121, 25 May 2023, Pages 264-274

DOI : https://doi.org/10.1016/j.jiec.2023.01.030

ABSTRACT

The separation of tritium (3H) from radioactive wastewater is a persistent challenging problem in the nuclear industry from an environmental perspective. This study provides new insight into the tritium separation by investigating hydrogen isotope-selective exchange reaction on hydrogen-bonded fluorine (F····H····O) site. In this study, fluorinated mesoporous silica, F-MCM-41_NCs were prepared as a novel tritium sorbent that showed a significantly enhanced tritium isotope separation factor (α) compared to the pristine MCM-41 (α = 1.2). The optimal α of 3.3 is achieved using 0.5F-MCM-41_NC prepared with 0.5 g of NH4F per gram of MCM-41. This optimal α is attributed to an excellent compromise between the amount and the stability of (NH4)2SiF6 on the pore channel with the integrity of the MCM-41 framework. Experimental, theoretical, and analytical characterization results consistently support chemical affinity quantum sieving effect at F····H····O hydrogen-bonding sites via the hydrogen isotope-selective exchange reaction as the dominant tritium separation mechanism.