(175d) Low-Level Radionuclide Removal from Water Sources Using Waste-Derived Biochars Followed By Adsorbent Combustion

Low levels of heavy metals and radionuclides, such as uranium, can be the difference between a usable and an unusable water resource. Adsorption-based removal methods have the potential to be long-lasting for low-level metal concentrations over large volumes of water. The adsorption and removal of radionuclides from water using biochars derived from abundant and low-cost wastes has been seen as a promising alternative. In this study, the feedstocks (pecan wood, cattle manure, and hemp residue) were converted into biochars in a 5-L lab pyrolyzer at 400–500°C under nitrogen flow. Batch uranium adsorption studies were conducted for the effects of initial concentration, solution pH, contact time, and competing ions. Adsorption isotherms and kinetic models constructed from concentration measurements before and after adsorbate contact. After adsorption, loaded biochars were combusted in a tube furance and the fractionation of radionuclides tracked between the gas/vapor and ash fractions. Data on radionuclide fractionation during combustion wil be used to understand the potential of radionuclide adsorption and radioactive waste volume reduction without needing to regenerate the adsorbents.