Study of hexacyanoferrate(II) nanodiamond adsorbent for the preconcentration of cesium and size categorization of radiocesium particles from contaminated soil

2021 Summer.Includes bibliographical references.High levels of radioactive cesium (RCs) were released into the environment as a result of the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Wide areas, including residential and farming spaces, were contaminated to varying degrees with 134Cs and 137Cs which has presented complications with soil and water utilization for personal use. The current decontamination efforts used to remove RCs from the topsoil have been costly and created new challenges in storing low-level radioactive waste. Meanwhile, determining low levels of radioactivity in the environment is a challenge in itself, since changes in sample composition and self-shielding coupled with the sample amount required to meet low minimum detection limits lead to inaccurate measurements. This project investigates the use of a hexacyanoferrate(II) nanodiamond adsorbent to preconcentrate dissolved Cs in contaminated solutions in order to improve the counting efficiency and accuracy for low activity samples. Also, the determination of the size of particle attached radiocesium from previous soil samples that have undergone sequential extraction was attempted in order to study how particle size affects migration and deposition behavior. The majority of the preconcentration studies yielded over 98% 137Cs adsorption. Further investigation into preconcentration studies is recommended to test adsorbent performance in more dynamic conditions. Meanwhile, activity measurement of 0.45 μm, 0.2 μm, and 0.1 μm filters for Cs-137 indicated that the vast majority of the extracted RCs in the fractions obtained by sequential extraction was in a dissolved form. Therefore, the RCs that was extracted from the soil is not present in the form of microparticles with an activity greater than 5 Bq. This research was supported by grant T42OH009229 funded by the National Institute for Occupational Safety and Health (NIOSH) from the Centers for Disease Control and Prevention (CDC). No known conflict of interest exists within this study