Yttrium oxide (Y₂O₃) nanocrystallites were synthesized by mean of a sol-gel method using two different precursors. Raw materials used were yttrium nitrate and yttrium chloride, in methanol. In order to promote oxygen vacancies, P-123 poloxamer was incorporated. Synthesized systems were heat-treated at temperatures from 700 °C to 900 °C. Systems at 900 °C were prepared in the presence and absence of P-123 using different molar ratios (P-123:Y = 1:1 and 2:1). Fourier transform infrared spectroscopy (FTIR) results revealed a characteristic absorption band of Y–O vibrations typical of Y₂O₃ matrix. The structural phase was analyzed by X-ray diffraction (XRD), showing the characteristic cubic phase in all systems. The diffraction peak that presented the major intensity corresponded to the sample prepared from yttrium chloride incorporating P-123 in a molar ratio of P-123:Y = 2:1 at 900 °C. Crystallites sizes were determined by Scherrer equation as between 21 nm and 32 nm. Antioxidant properties were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assays; the results are discussed.

A choline chloride/urea natural deep eutectic solvent (ChCl NADES) was prepared via a green chemistry method and used to leach Zn and Mn oxides from conventional Zn–C scrap batteries. FTIR and ¹H NMR spectroscopy were used to characterize the NADES. The leaching kinetics of the Zn and Mn oxides was monitored at isothermal conditions (80, 100, 125, and 150 °C) and at two solid/NADES ratios: 3.3 and 10 g dm⁻³. It was possible to dissolve Zn and Mn oxides under all of tested conditions, reaching more than a 95% recovery for both metals at 150 °C after 90 min, whereas, at 25 °C, it was possible to leach up to 90% of the Zn and 30% of the Mn after 4320 min (72 h). Furthermore, the leaching kinetics was controlled by the boundary layer, coincident with a shrinking core model. According to the Arrhenius plot, the activation energy for Zn ranges from 49.13 to 52.21 kJ mol⁻¹, and that for Mn ranges from 46.97 to 66.77 kJ mol⁻¹.