Radiation effects on the dissolution kinetics of magnetite and hematite in EDTA- and NTA-based dilute chemical decontamination formulations

Ethylene diamine tetraacetic acid (EDTA)- and nitrilo triacetic acid (NTA)-based formulations such as citric acid (CA)/EDTA/ascorbic acid (AA), CA/EDTA/gallic acid (GA), CA/NTA/AA and CA/NTA/GA were used for dissolving magnetite and hematite under similar experimental conditions of temperature, amount of the oxide and the concentration of the formulations (close to stoichiometric conditions). In unirradiated solutions, EDTA-based formulations were more efficient in dissolving these oxides than NTA-based formulations. Similarly, formulations containing AA as reductant gave better results as compared to formulations containing GA as reductant in unirradiated solutions. However, in gamma-irradiated formulations, the efficiency of dissolution was affected to a much greater extent in EDTA and AA containing formulations as compared to NTA and GA containing formulations. Both NTA and GA were found to be less prone to radiation degradation as compared to EDTA and AA.