Eco friendly obtained zirconium oxide crystals for efficient separation of rare earth elements from acidic media

This study examined synthesis of zirconium oxide (ZrO₂) using a straightforward green synthesis method and its application for preferential adsorption of La³⁺, Eu³⁺, and Sm³⁺, demonstrating a low-cost and environmentally friendly approach. Several analytical techniques were employed to characterize (ZrO₂) specifically, XRD, TGA-DTA, SEM-EDX, and FTIR. Through batch mode experiments, the effectiveness of ZrO₂ to adsorb Eu³⁺, La³⁺, and Sm³⁺ ions was rigorously evaluated. The ideal conditions for lanthanides removal were determined by carefully controlling and optimizing key adsorption factors, including reaction temperature, starting metal concentration, adsorbent mass, contact time, and solution pH. Furthermore, pH 3.5, contact duration of 240.0 min, adsorbent weight of 0.05 g, and starting concentration of 100 mg/L are the optimal conditions for removing La³⁺, Eu³⁺, and Sm³⁺ ions onto ZrO₂. Kinetic modeling revealed that the results were most accurately represented by the pseudo-second-order model, which provided the most accurate for characterizing the adsorption procedure. The obtained data exhibited a resilient correlation to Langmuir and Freundlih models. The thermodynamic analysis further showed that La³⁺, Eu³⁺, and Sm³⁺ adsorbed spontaneously and endothermically on ZrO₂. Reusability assessments demonstrated the adsorbent's efficacy over five regeneration cycles. Thus, the promising affinity of ZrO₂ for preferential adsorption of La³⁺, Eu³⁺ and Sm³⁺ ions from acidic media is useful.