NiAlCe mixed oxides obtained from layered double hydroxides applied to anisole hydrodeoxygenation

Ce4+-Substituted Ni-Al mixed oxide: fluoride adsorption performance and reusability

In this study, Ce4+-doped Ni-Al mixed oxides (NACO) were synthesized and comprehensively characterized for their potential application in fluoride adsorption. NACOs were examined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM), revealing a sheet-like morphology with a nodular appearance. X-ray diffraction (XRD) analysis confirmed the formation of mixed oxides of cubic crystal structure, with characteristic planes (111), (200), and (220) at 2θ values of 37.63°, 43.61°, and 63.64°, respectively. Further investigations using X-ray Photoelectron Spectroscopy (XPS) identified the presence of elements such as Ni, Al, Ce, and O with oxidation states +2, +3, +4, and -2, respectively. The Brunauer-Emmett-Teller (BET) analysis indicated that NACO followed a type IV physisorption isotherm, suggesting favorable surface adsorption characteristics. The adsorption kinetics was studied, and the experimental data exhibited a good suit to both pseudo-first order and pseudo-second order, as indicated by high R2 values. Moreover, the Freundlich isotherm model demonstrated a good fit to the experimental data. The result also revealed that NACO has a maximum capacity for adsorption (qmax) of 132 mg g-1. Thermodynamic studies showed that fluoride adsorption onto NACO was feasible and spontaneous. Additionally, NACO exhibited excellent regeneration capabilities, as evidenced by a remarkable 75.71% removal efficiency at the sixth regeneration stage, indicating sustained adsorption capacity even after multiple regeneration cycles. Overall, NACOs displayed promising characteristics for fluoride adsorption, making them potential candidates for efficient and sustainable water treatment technologies.

Layered Double Hydroxides Containing Rare Earth Cations: Synthesis and Applications

In this mini-review, we describe the currently available literature concerning synthesis and applications of layered double hydroxides (LDHs) containing rare earth cations (RE-LDHs), focusing on the catalytic activity of those compounds. The lack of studies of some rare earth elements (REE) and the insufficient knowledge of their catalytic activity in the structure of LDHs indicate the need for further research.