Layer-stacked network hybrid aerogels for the adsorption of U(VI): Concentration screening, efficient recovery, and cycle mechanism

Uranium contamination is a key issue in the sustainable development of nuclear energy. In this study, a cellulose/sericite hybrid aerogel with a layer-stacked network structure (MCC/AS-P) was prepared for uranium-contaminated wastewater treatment. Systematic characterization and multiple-batch static adsorption experiments were conducted to analyze the aerogel's preparation, adsorption, and desorption. The kinetics demonstrated a noticeable transition between mass transfer diffusion control and mass transfer control, approaching adsorption equilibrium within 8 min and 180 min, respectively, wherein polymer layers led to a more stable adsorption process. Adsorption isotherm and thermodynamic studies established that the theoretical adsorption capacity of MCC/AS-P for U(VI) at T = 298 K could reach 374.5 mg.g(-1). The adsorption behavior was endothermic and spontaneous, and the DFT calculations demonstrated that the adsorption energy of MCC/AS for UO22+ was 506.5 kcal/mol. Temperature, U(VI) concentration, and desorption can all lead to a transition of the dominant mechanism between chemisorption and physisorption. After six swelling-deswelling adsorption cycles, the adsorption efficiency remained above 80%, and the structure remained intact. Furthermore, the excellent performance in terms of interference resistance and chemical stability offers potential for practical application.