Nitrogen-Doped Hierarchically Porous Bio-scaffold with a Coordination-Active Interface for Superior Pertechnetate (TcO₄^-) Sequestration

Long-lived and highly mobile pertechnetate (TcO₄^-) poses a persistent challenge for radioactive-wastewater treatment, particularly in the presence of competing anions. Herein, a nitrogen-doped architected super-porous bio-scaffold (NASB) was prepared from Alocasia macrorrhiza stems. NASB exhibited a high TcO₄^- adsorption capacity, with rapid and spontaneous uptake that followed a pseudo-second-order kinetic model. It enabled preferential TcO₄^- uptake even in the presence of a 100-fold molar excess of NO₃^-. Spectroscopic analyses and theoretical calculations indicate that TcO₄^- sequestration mainly results from enhanced site accessibility. Nitrogen doping remodeled the interfacial electronic structure and strengthened TcO₄^- binding, with graphitic N showing the most favorable adsorption energy of -48.273 kJ/mol. These results demonstrate that combining biomass-derived porosity with nitrogen functionalization provides a carbon platform for TcO₄^- immobilization in complex radioactive wastewater.