EDTA-functionalized mesoporous silica for the removal of corrosion products: Adsorption studies and performance evaluation under gamma irradiation

Abstract

Ethylenediaminetetraacetic acid functionalized mesoporous silica (EDTA-SBA-15) was synthesized and used to efficiently remove corrosion products like Co(II), Ni(II), and Cu(II) generated in nuclear reactor coolants. The mesoporosity, long range order, and functional group loadings were confirmed by N-2 adsorption/desorption, small angle x-ray scattering (SAXS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The improved loading of EDTA on the SBA-15 surface significantly increased its adsorption capacity (1.33-1.44 mmol/g) for the above-mentioned corrosion products. Additionally, the fast equilibrium adsorption kinetics (<20 min) was observed, and the experimental data fitted the pseudo second order model. Complete sequestration of Co(II), Ni(II), and Cu(II) from their equimolar mixture was achieved with the optimum adsorbent dose. EDTA-SBA-15 had good stability over a wide pH range from 1 to 6 as well as in concentrated ionic media and at temperatures up to 75 degrees C. This study further evaluated the performance of the EDTA-SBA-15 under gamma irradiation. The results suggest that it has potential for use in the decontamination of radioactive corrosion products from the primary coolant system of nuclear power plants. (C) 2017 Elsevier Inc. All rights reserved.