Synthetic and natural antibacterial carbon adsorbents for clinical nuclear waste management

Abstract

Patients undergoing high-dose radioiodine ablation (RAI) therapy in Nuclear Medicine Department need to be isolated in a special designed ward for a few days. Large amount of clinical radioactive wastewater from patient body is produced during high-activity RAI therapy. The radioactive wastewater needs to store in a delay tank until the radioactivity decayed below acceptable limit before being discharged and indirectly limit the patient admission and treatment. This study is to propose an alternative antibacterial adsorbent for I-131 extraction from clinical radioactive wastewater at the nuclear medicine department using graphene oxide silver (GOAg) and bamboo activated carbon (BAC). The synthesised adsorbents and their sediments (filtered sample) were analysed using field emission scanning electron microscopy (FESEM) for morphological analysis and analysed using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). XPS spectra for C 1s adsorbents show intensity peaks at 284.45 eV (C=C) and 285.3 eV (C–C) for GOAg and its sediments, and 284.35 eV (C–C), 287.00 eV (C=O), and 290.07 eV (π–π∗ transitions) for BAC and its sediments. FTIR spectra reveal various functional groups of adsorbents: C=C (1637.50772 cm−1), C=O (1340.48041 cm−1), and C–O–C (1031.88060 cm−1) for GOAg and its sediments, and C=C (1635.57897 cm−1), C–C (1257.54421 cm−1), and C–O (1188.10925 cm−1) for BAC and its sediments. XRD patterns exhibit peaks at 2θ = 27.82°, 29.39°, 32.24°, and 46.22°, which can be attributed to the (002) diffraction plane, (220) crystallographic plane, (111) plane of Ag2O, and (200) crystallographic plane, respectively, for GOAg and its sediments. Meanwhile, the peaks at 2θ = 26.56° and 42.41°, which correspond to (002) and (100) planes, respectively, for BAC and its sediments. The d-spacing and the crystallinity index of each adsorbent were also determined. The estimation of the remaining β− particles during the adsorption of I-131 was carried out using PHITS. The finding of this study is beneficial for alternative radionuclide extractions technique from clinical radioactive wastewater in nuclear medicine.

Keywords: Nuclear Medicine, Radioactivity, Adsorption, Morphological Changes, Structural analysis