Adenosine triphosphate-functionalized graphene oxide for selective recovery of Nd(iii) and Y(iii): synthesis,...

The development of bio-functionalized nanomaterials provides an effective pathway toward sustainable recovery of rare earth elements (REEs) from aqueous systems. In this work, adenosine triphosphate-functionalized graphene oxide (GO-ATP) was synthesized through covalent immobilization of ATP onto GO nanosheets, generating a multifunctional interfacial surface enriched with phosphate and hydroxyl donor groups. Comprehensive characterization using FTIR, SEM/EDX, BET, XRD, and TEM confirmed successful ATP grafting, increased surface heterogeneity, and the preservation of structural integrity. Batch adsorption experiments demonstrated high affinities toward Nd³⁺ and Y³⁺, with rapid equilibrium attainment and excellent correlation with the pseudo-second-order kinetic model, indicating chemisorption controlled uptake. The Langmuir isotherm adequately described the sorption behavior, suggesting monolayer adsorption, while thermodynamic parameters revealed a spontaneous and endothermic process. Mechanistic interpretation based on HSAB theory and surface complexation concepts showed that REE ions coordinate strongly with phosphate oxygen and nucleophilic nitrogen sites of ATP, forming stable inner-sphere complexes. The GO-ATP adsorbent also exhibited remarkable selectivity and reusability, maintaining >90% removal efficiency over repeated cycles. These findings highlight GO-ATP as a green, biocompatible, and highly selective platform for REE recovery and advanced water purification applications.