The sustainable recovery of rare earth elements (REEs) from secondary resources is essential as demand rises and primary ores face economic and environmental constraints. Here, a tris-phosphorylated Schiff-base ligand (PTREN) is rationally constructed as a molecular adsorbent for highly selective uptake of Sm3+ from spent SmCo magnet leachates. The three phosphonic acid groups create a pre-organized, multidentate O-donor pocket tailored for inner-sphere Sm3+ coordination. PTREN was thoroughly characterized by FTIR, NMR, XPS, TGA, BET, and MALDI-TOF, confirming its discrete structure and stable phosphonate functionality. Batch experiments show fast kinetics (equilibrium in 45 min) and a high Langmuir capacity of 469.4 mg g-1 at pH 5.0. Isotherm, kinetic, and thermodynamic analyses collectively indicate monolayer chemisorption, a spontaneous and endothermic process, and increased interfacial disorder upon binding. Sm3+ is efficiently desorbed with 0.5 M HNO3 and converted to high-purity Sm2O3 nanoparticles, closing the material loop. PTREN maintains over 85% of its initial capacity after nine adsorption - desorption cycles, evidencing excellent structural robustness and regenerability. This work introduces a tunable phosphonate-based molecular platform that couples selective Sm recovery from complex waste streams with direct generation of value-added oxide products, advancing circular REE recycling. A full list of abbreviations and acronyms used throughout this manuscript is provided in Table S-1 of the Supporting Information.
Breast cancer treatment often involves the administration of paclitaxel (PTX), a chemotherapy drug. Recently, there has been growing interest in utilizing metal nanoparticles (NPs) to deliver PTX to cancerous cells. In this study, a novel chitosan-coated ZnO/MgO nanocarrier (ZnO/MgO-CS) was engineered for the efficient adsorptive separation and pH-responsive release of PTX. Thermogravimetric analysis indicated a coating of 85%, and the chitosan layer significantly enhanced the drug loading efficiency to 98.53%. The adsorption capacity of the nanocarrier reached 76.54 mg/g within 14 min, following the Ho and McKay adsorption kinetics (R-2 > 0.99), suggesting a chemisorption-driven separation mechanism. The impact of argon cold plasma treatment on adsorption performance was also assessed. Drug release studies revealed a biphasic release profile: an initial burst release followed by sustained release, with nearly 97% cumulative release after 24 hours. The release behavior conformed to Korsmeyer-Peppas and Peppas-Korsmeyer kinetic models, indicating diffusion-controlled separation. Morphological analysis confirmed a mesoporous structure with uniform pore distribution. Cytotoxicity evaluation via MTT assay demonstrated that the synthesized carrier maintained biocompatibility while enhancing the therapeutic impact of PTX against MCF-7 breast cancer cells. These results highlight the potential of ZnO/MgO-CS as a promising nanoplatform for selective separation and sustained release of anticancer agents.
