Characterization of GO:I-131 for Radioactive Clinical Waste Water Management in Nuclear Medicine

Abstract

Iodine-131 (I-131) mostly used in nuclear medicine for radioiodine ablation (RAI) therapy and hyperthyroid treatment. Patient was orally ingested I-131 and warded within 3 to 4 days for RAI therapy, whereas outpatient for hyperthyroid treatment. Radioactive waste from patient’s body such as urine and feces were eliminated from the ward into delay tank. Delay tank is an underground system to reduce radioactivity of contaminated I-131 clinical waste water at certain level before will be discharged into ordinary sewage system. Delay tank indirectly restricted the number of patient admission due to its periodical clearance and small volume size. Thus, a new technique to extract I-131 radionuclide with contaminated mixtures in solid form from the delay tank has been proposed as an alternative for clinical waste water management in nuclear medicine. Radioactive clinical waste water samples from delay tank were mixed with Graphene Oxide (GO) with varies in concentrations before filtered using micro pore filter paper. After 15 – 30 minutes, the radioactivity of the water residue left beneath the filter paper were counted using well counter. The measurements were repeated on fourth, eighth, twelfth and sixteenth days, which is significant to the natural decay of I-131 radionuclide. The water residue radioactivity decreases over the concentration of GO throughout the experiment. The mixtures of GO:I-131 (sediment formed on the filter paper) were analyzed using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-rays (EDX) for morphology and elemental analysis. FESEM image revealed the maximum GO concentration produced high agglomeration morphology. EDX shows I-131 and other elements were attracted to GO layered sheets. The results showed that the GO had high sorption capacities in the removal of radionuclides, which was attributed to the large number of oxygen-containing functional groups on the surface or edge sites.