Radiation-Induced Processes in Commercially Available Samples of Activated Carbon Under the Influence of Gamma- and Beta-Radioactivity

Commercially available adsorbents, based on activated carbon, are often used to purify water solutions from organic pollutants, dyes, heavy metal ions, and radionuclides. Therefore, the investigations of radiation-induced processes in carbon adsorbents are relevant. This work investigates the effect of gamma- and beta-radiation on activated carbon's structure and adsorption properties. The commercially available activated carbon samples were irradiated by a linear accelerator, Halsyon Varian, and a 90Sr-90Y source, Sirius, in the air atmosphere and acidic and neutral water solutions. The adsorption characteristics of irradiated and non-irradiated carbon toward Na-EDTA molecules were studied. The Raman spectrometry was used to control the radiation-induced change in the carbon structure. The Raman spectra were fitted using fityk-1.3.1-setup.exe software. The maximum adsorption of Na-EDTA molecules by non-irradiated AC reaches 800 mg/g. Irradiation with beta- and gamma radioactivity in the air atmosphere does not affect the adsorption capacity of activated carbon, which is also capable of adsorbing the Na-EDTA complex with strontium ions. During irradiation of AC in the presence of water molecules on the surface, the –C–O–C– groups, aromatic rings, and carboxylic acid dimers form on the surface of AC, which lead to maxima of about 810 cm – 1, 990–1100 cm – 1, and 910–960 cm – 1 on the Raman spectrum of AC. Fitting spectrum using program fityk-1.3.1-setup.exe shows that these transformations of the activated carbon surface involve mainly sp3-hybridized atoms. Irradiation of activated carbon in this way negatively affects the adsorption capacity. However, this effect requires further research.