Adsorption of radioactive iodine and krypton from off-gas stream using continuous flow adsorption column

Abstract

A novel Engelhard Titanosilicate – 10 (ETS-10) supported 10wt% hollow carbon nano-polyhedron (10wt% C@ETS-10) sorbent developed in our laboratory was investigated for adsorption of the radioactive iodine and krypton from off-gas stream using a continuous flow adsorption column. Adsorption experiments were performed to determine the capacity of 10wt% C@ETS-10 sorbent for iodine and krypton in multicomponent mixture system by varying operating parameters, such as inlet concentration of iodine (I2) and krypton (Kr), and adsorption column temperature. Pristine and used sorbents were characterized by scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy to identify the morphology, elemental and vibration analysis of the sorbent before and after the experiments. EDS and XPS spectra of the used samples clearly indicate the presence of iodine on the sorbent. Multicomponent sorption capacities of I2 and Kr of 10wt% C@ETS-10 sorbent calculated from the breakthrough curves at 20°C at 25ppm I2 and 70ppm Kr balanced with nitrogen were found to be 41.5 and 0.0323mgg−1, respectively. Sorption data was found to be best fitted by the Langmuir as well as Freundlich isotherm model. Experimental data were analyzed by Thomas, Yoon-Nelson, and Bohart-Adams sorption kinetics models to predict the breakthrough curves and calculate the characteristic parameters of the column that are useful for process design for the multicomponent system. Results show that 10wt% C@ETS-10 sorbent has potential sorbent for adsorption of multicomponent (I2 and Kr) from off-gas stream.