Optimized activated carbon pellets for effective cobalt ion adsorption

Technologies for treating and removing the radioactive element cobalt, released during nuclear decommissioning, are necessary to address the health risks it poses to humans. A pelletized activated carbon material is considered the best option for effectively eliminating dissolved cobalt in water, addressing the physical constraints of traditional activated carbon. This study involved producing optimized activated carbon pellets by combining activated carbon with a polymer binder and a triethylenediamine (TEDA) attachment agent. The activated carbon pellets incorporating the TEDA attachment agent and polymer binder were used as adsorbents to observe the Co²⁺ adsorption characteristics based on attachment concentration, leading to the development of a combination of pellets with optimized adsorption capacity. It was confirmed that the C–N amine functional groups introduced by TEDA help to enhance interactions within the chemical adsorption environment with Co²⁺ ions. In experiments, the removal rates were 99.1% and 93.4% for AC@PU@0.2T with 20 wt% TEDA when treating Co²⁺ concentrations of 50 and 100 mg L⁻¹, respectively. It was confirmed that the pores inside the activated carbon were significantly reduced during the pelletization process, and high adsorption performance was maintained even after pelletization due to the chemical adsorption ability of TEDA added at the optimal ratio. It was identified that both physical and chemical adsorption mechanisms operate simultaneously, allowing effective adsorption of Co²⁺ ions while maintaining the physical properties of the pellets.