Green synthesis and advanced modeling of yttrium oxide nanoparticles for efficient antimony removal from contaminated water

Yttrium oxide nanoparticles (Y₂O₃ NPs) were synthesized via a green route using Pinus leaf extract and evaluated for Sb³⁺ removal from aqueous solutions. Structural characterization confirmed the formation of highly crystalline nanoparticles with an average size of approximately 16.4 nm. Batch adsorption experiments demonstrated a high maximum adsorption capacity of 228.54 mg/g. Equilibrium data were best described by the Langmuir isotherm, indicating monolayer adsorption, whereas kinetic data followed a pseudo-first-order model, indicating rapid Sb³⁺ uptake. Thermodynamic analysis showed that the adsorption process is spontaneous and exothermic (ΔG° < 0, ΔH° = −23.52 kJ/mol). Process optimization using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) showed excellent agreement with experimental results, with ANN providing superior predictive accuracy (R² > 0.99). Regeneration experiments demonstrated that the nanoparticles retained more than 62% of their adsorption capacity after eight reuse cycles, confirming their reusability. These results highlight the potential of green-synthesized Y₂O₃ nanoparticles as efficient, reusable adsorbents for removing Sb³⁺ from contaminated water.