2025 AIChE Annual Meeting

Carbon Black As a Scalable Adsorbent for Uranium(IV) and Radionuclide Remediation

Carbon black is an abundant, inexpensive, and high surface-area material with strong potential for radionuclide adsorption and environmental cleanup. This study investigates the optimal concentration of carbon black for adsorbing tetravalent uranium (U(IV)) from aqueous media and evaluates its overall performance as an adsorbent. Varying masses of carbon black pearls (0.01-1.5 g) were mixed with a 15 mL, 10 ppm U(IV) solution prepared from uranyl nitrate and hydrogen peroxide, then agitated, centrifuged, and filtered to separate solid and liquid phases. The supernatant was partially evaporated and treated with 2% HNO₃ to ensure compatibility with ICP-OES measurement. Calibration standards (0.06-10 ppm U) were developed to quantify residual uranium, while leaching with concentrated HNO3 verified uranium retention in the solid phase. Preliminary results indicate that excessive carbon black concentrations (~0.1 g mL-1) reduce adsorption efficiency due to sludge formation, limiting U(IV) surface contact and suggesting an optimal range within the tested interval. Future work will examine the effects of pH, temperature, and mild activation on adsorption behavior, as well as applicability to other radionuclides. Ultimately, this research aims to establish optimized application conditions for carbon black as a low-cost, scalable adsorbent for radioactive waste remediation.