Gamma spectrometry technique application to the 60Co sorption onto IRN-77 resin from radioactive wastewater: Equilibrium, Kinetic and Thermodynamic investigations

Abstract

The performance of synthetic ion exchange resin IRN-77 have been studied in this work in order to use it as an adsorbent to remove radioactive isotope 60Co from nuclear wastewater by the sorption process, using the gamma spectrometry technique. The resin simple was identified using SEM and FTIR infrared spectrometry. The gamma radiation acquisition emitted from the fixed radioactive ⁶⁰Co onto IRN-77 solid samples was carried out using the gamma spectrometry chain, equipped with an HPGe semi-conductor detector with high-resolution. Various factors were considered for the sorption process study such as ⁶⁰Co concentration, contact time and temperature. The maximum adsorption capacity of the IRN-77 samples was determined by studying the adsorption isotherms; Kinetics models including thermodynamics were also studied and investigated. The experimental results showed that the adsorption reaction was adjustable to the pseudo-first-order and the Langmuir model was found to describe best the experimental results by obtaining a very important maximum adsorption quantity of 10.620 µCi of ⁶⁰Co per 1 gram of IRN-77 adsorbent. A dimensionless separation factor R_L was used to judge the favorable adsorption. The adsorption capacity of ⁶⁰Co ions onto IRN-77 particles increased with the increasing of temperature. The values of the thermodynamic parameters have shown that the ⁶⁰Co ions adsorption process was endothermic and favored at high temperatures with a positive value of the enthalpy ∆H° of 23,54 kJ/mol. The free energy’s values ∆G◦ are positive over the whole temperature range. The specific activities of the fixed ⁶⁰Co radionuclide allow evaluating the solid samples IRN-77 resin's sorption capacity.