Wasp Nest as a Natural Cellulose–Protein Biocomposite Material: Integrated Investigation of Structural Properties, Microbiota and Uranium Adsorption Performance

Abstract This research explores the structural attributes, microbial composition, and potential application of wasp nest material (WN) as a natural biocomposite for uranium adsorption from aqueous solutions. The physicochemical properties of WN were characterized using FTIR, SEM, EDX, BET, and XPS methodologies. The study systematically assessed the impact of variables such as initial uranium concentration, pH, contact time, temperature, and adsorbent dosage on the adsorption efficiency. The adsorption isotherm adhered to the Langmuir model, demonstrating a maximum adsorption capacity of 1.169 mol kg–1. The Freundlich heterogeneity factor was calculated to be 0.43, while the D–R model indicated an adsorption energy of 10.4 kJ mol–1, pointing to chemisorption. Kinetic analysis revealed that the Elovich model best described the data, with an initial adsorption rate of 114.4 mol kg–1 min–1. The positive enthalpy values confirmed the endothermic nature of the adsorption, and the negative Gibbs free energy values suggested spontaneity. XPS analysis confirmed the adsorption of U(VI) on WN, with U 4f 7/2 and U 4f 5/2 peaks at 381.8 and 392.6 eV, respectively, indicative of uranyl species and their chemical interaction with oxygen-containing functional groups on the biocomposite surface. The microbial community within WN may influence the adsorbent’s performance by secreting extracellular polymeric substances (EPS), potentially enhancing uranium binding through enrichment of functional groups. These findings underscore the potential of wasp nest material, a natural and environmentally friendly cellulose-based protein-containing biocomposite, as a viable option for uranium removal from aqueous solutions.