[Co–Al–Cl] layered double hydroxide (LDH) obtained by co-precipitation at constant pH 8 presented a single phase in a hexagonal unit cell parameters similar to the hydrotalcite (JCPDS 14-191) belonging to the rhombohedral crystal system and space group R(-3)m. The adsorption kinetics of 2,4-D onto [Co–Al–Cl] LDH was better described by the Pseudo Second-Order (best adjust R2 = 0.9998 for 60 mg L−1 2,4-D adsorption). Intra-particle diffusion model was not the sole rate-controlling factor, indicating the adsorption of 2,4-D by the [Co–Al–Cl] LDH is a complex process for the experimental conditions performed, involving both boundary layer and intra-particle diffusion. The adsorption isotherm adjusted better to the Freundlich model (R2 = 0.9845) and the ΔH° value of - 51.18 kJ mol−1 indicated the predominance of the physical adsorption. The FT-IR spectrum of LDH after adsorption presented 2,4-D bands together with those of LDH and XRD showed an increase in the interlamellar distance (d003) due to the intercalation of 2,4-D in the interlayer structure of the [Co–Al–Cl] LDH, corroborating inter and intra-particle adsorption data. Thus, [Co–Al–Cl] LDH, commonly used as electrodes in supercapacitors, can be effectively used as an adsorbent for the removal of 2,4-D from contaminated waters.

The composite LiFePO 4 /polyaniline was prepared by chemical synthesis to promote the intensification of the electrochemical properties for use as cathodes in lithium ion batteries. The X-ray diffraction (XRD) of LiFePO 4 synthesized by solvothermal method were indexed to the orthorhombic structure, according to the JCPDS 40-1499. The spectra Raman and FTIR showed a high degree of ordering of LiFePO 4 with interaction between LiFePO 4 surface with structure conjugate of conducting polymers. The cyclic voltammogram of the composite synthesized chemically showed a significant reduction in the value of ΔE p (ΔE p = 0.20 V) when compared to LiFePO 4 (ΔE p = 0.41 V), with lower charge transfer resistance values, indicating favoring electron transfer rate in the composite. Thus, the alternative synthesis route of the LiFePO 4 / PAni composite was easy to handle and allowed an increase in the electrochemical properties of the LiFePO 4 , compared to the traditional methods that require additional thermal treatments.

The aim of this paper was the recovering of the cathodic material from discarded lithium ion batteries for obtainment of the lamellar double hydroxides (LDHs) by the co-precipitation method at variable pH in HCl and H 2 O 2 1:1 (v/v) acid solution containing Co and Al (extracted from cathodic material composed of LiCoO 2 and aluminum foil). These metals were precipitated in LiOH at pH 9 or 11, or NH 4 OH at pH 9 and submitted to the hydrothermal treatment (HT) to improve the structural organization of the LDHs lamellae. After precipitation, the resulting solids were structurally characterized by XRD for phase identification and calculation of the unit cell parameter, thermally by TGA for the identification of the mass loss and morphologically by SEM. The sample obtained by precipitation with LiOH at pH 11 / hydrothermal treatment showed diffraction peaks similar to hydrotalcite, morphological and thermal characteristics similar to the pattern Co-Al-Cl LDH obtained by co-precipitation at constant pH 8. Keywords: lithium ion batteries, LiCoO 2 and aluminum foil recovering, reprocessing of cellular phone battery and lamellar double hydroxides

) were prepared by Pechini synthesis using lithium and manganese acetates, citric acid, ethylene glycol, and the respective oxide or acetate of the doping ions in molar ratios of 2.00 (Mn 1.98 + M 0.02 ) to 1.05 Li. The TGA/DTA of the precursor gels showed weight loss/energy relative to crystallization below 450 ºC. From the XRD, a single cubic phase (F D3M ) was identified for the all-doped or undoped oxides after only 2 h calcination. The unit cell parameters a for both aluminum-and gallium-doped oxides calcined at 750 °C for 2 h (8.212 Å and 8.210 Å, respectively) were higher than that for the undoped oxide (8.199 Å). The crystallite sizes ranged from ~ 20 nm to 70 nm, conferring nanometric character. The specific capacities decreased in order: C discharge (Li

In this work nanostructured Li 1.05 Mn 2 O 4 oxide was obtained by Solution Combustion Synthesis (SCS) using three different fuel agents in order to obtain a unique phase with a crystalline cubic structure belonging to the F d3m spatial group. The phase of interest could be obtained, following the order: glycine (at 600 °C for 2 h) < urea (at 750 °C for 2 h) < maleic anhydride (at 750 °C for 4 h), with crystallite size in the range from 4.6 to 9.7 nm (nanometric character) and the unit cell parameter of the calcined samples at 750 °C for 2 h were similar to the JCPDS 35-0782 with cubic structure (a = 8.247 Å). Charge and discharge tests from the samples obtained by glycine fuel (at 750 °C for 4 h) presented the highest experimental specific capacities of 115 mA h g -1 and 92% of retention after 10 cycles.