Synthesis and characterization of a high-performance TiO ₂ -ZrO ₂ /PA/AC composite for radionuclide removal from aqueous environments

This study reports the synthesis and characterization of a novel composite material, TiO 2 -ZrO 2 /PA/AC (titanium dioxide, zirconium dioxide, phosphonic acid, and activated carbon), fabricated via the sol-gel method for radionuclide removal. Characterization (XRD, SEM, FTIR, EDX) confirmed the successful integration of components and a functional surface structure. The composite’s adsorption behavior toward Cs(I), Sr(II), Pu(IV), and U(VI) was investigated in aqueous solution. Adsorption efficiency was observed to increase with pH and temperature. Isotherm analysis revealed the Langmuir model as the best fit, suggesting monolayer coverage, with the maximum adsorption capacity (Q 0 ) being highest for Sr(II) (467.83 mg/g at 310 K). Kinetic analysis confirmed the process is governed by the pseudo-second-order model, indicating a dominant chemisorption mechanism. The diffusion coefficients were found to increase with temperature, reinforcing the endothermic nature of the process and suggesting faster intraparticle transport at elevated temperatures. Furthermore, desorption studies demonstrated the composite’s excellent reusability, maintaining approximately 80% recovery efficiency after four cycles with HNO 3 . These findings establish the TiO 2 -ZrO 2 /PA/AC composite as a highly promising, stable, and efficient adsorbent for practical application in nuclear waste management. The composite establishes an efficient, stable, and reusable adsorbent for practical nuclear waste management.