Engineered Activated Carbons for Multi-Radionuclide Removal from Real Low-Level Radioactive Wastewater

Low-level radioactive wastewater requires effective treatment to minimize risks to human health and the environment. This study evaluated the performance of activated carbons derived from regional biomass (Gurgurey, Pine, and Debregeasia woods) and Thar coal for the simultaneous removal of radionuclides (¹³⁷Cs, ¹³⁴Cs, ¹²⁴Sb, and ¹²²Sb) from real low-level radioactive wastewater. The activated carbons were characterized by proximate analysis and Fourier Transform Infrared Spectroscopy (FTIR), and their adsorption performance was investigated through batch experiments followed by kinetic and isotherm modeling. Among the investigated materials, activated carbons derived from Gurgurey wood, Pine wood, and Thar coal exhibited superior physicochemical properties, including low moisture (3.8-4.8%), low volatile matter (10.7-15.3%), high fixed carbon content (77.8-84.3%), and adsorption capacities ranging from 205.6 to 251.9 Bq g^-1. In contrast, Debregeasia-derived activated carbon showed the poorest performance owing to its high moisture, volatile matter, and ash contents, resulting in adsorption capacities of only 53.4-161.2 Bq g^-1. FTIR analysis confirmed the presence of phosphate-containing functional groups on all biomass-derived activated carbons except Thar coal. The adsorption data were best described by the pseudo-second-order kinetic model and the Langmuir isotherm, indicating that chemisorption and monolayer adsorption were the dominant removal mechanisms. These findings demonstrate that activated carbons derived from Gurgurey wood, Pine wood, and Thar coal are promising low-cost adsorbents for the simultaneous removal of multiple radionuclides from real low-level radioactive wastewater and provide a sustainable approach for radioactive wastewater treatment.