Green and Efficient Al-Doped LaFe_xAl_1–xO₃ Perovskite Oxide for Enhanced Phosphate Adsorption with Creation of Oxygen Vacancies

Abstract

La-based metal oxide materials are environmentally friendly and show promise for phosphate adsorption. A series of Al-doped perovskite oxides, such as LaFe x Al 1−x O 3 , were prepared using a facile citric acid-assisted sol−gel method. The characterization results demonstrated that with optimized Al doping, there was a significant increase in the specific surface area and increased defect content of perovskite oxide LaFe x Al 1−x O 3 . Adsorption experiments showed that the performance of phosphate removal by LaFe x Al 1−x O 3 was largely enhanced due to the improved adsorption capacity, which is maximum eight times higher compared with control perovskites prepared under neutral conditions. The mass transfer rate for adsorption was considerably boosted with phosphate removal within the initial 15 min. Spectroscopy analysis and density functional theory calculation results showed that the process of phosphate removal by the Al-doped perovskite oxides LaFe x Al 1−x O 3 involved electrostatic interactions, an inner-sphere complex, and surface oxygen vacancies, among which the creation of oxygen vacancies caused by the Al doping was the predominant mechanism for reducing the bonding barrier during adsorption and generating adsorption sites. The results enable the development of a green and efficient perovskite adsorbent with a La-based perovskite material for phosphorus removal.

Accelerating Charge Separation and CO2 Photoreduction in Aqueous Phase under Visible Light with Ru Nanoparticles Loaded on Ga-Doped NiTiO3 in a Batch Photoreactor

“…In the EPR analysis, we observed a prominent peak of increasing intensity for the GNTO samples at g factor = 2.004, corresponding to the oxygen vacancies in the octahedral sites of the lattice. 43 This observation is consistent with the XRD result in Figure 3a, which indicates that oxygen vacancies were created when Ga 3+ ions replaced Ti 4+ ions. The Ga ions inserted near the surface of the NTO particles form surface oxygen vacancies (V OS ), which Yu et al 45 reported for other systems to facilitate the adsorption of reactant gases and thus enhance catalyst performance.…”

“…Previous studies have proposed that oxygen vacancies can be induced in perovskite oxides by doping cations with a lower oxidation state than the host ions. , We looked for evidence of oxygen defects in GNTO and Ru-GNTOs lattice structures using EPR analysis (Figure b). In the EPR analysis, we observed a prominent peak of increasing intensity for the GNTO samples at g factor = 2.004, corresponding to the oxygen vacancies in the octahedral sites of the lattice . This observation is consistent with the XRD result in Figure a, which indicates that oxygen vacancies were created when Ga 3+ ions replaced Ti 4+ ions.…”

Composites hybridized with Ca(OH)2 and LaMnO3 synergistically improve phosphate adsorption properties

“…To the best of our knowledge, as a new adsorbent material, only three existing studies are available on the phosphate adsorption of perovskites. 9,10 These studies reported that phosphate adsorption is greatly affected by the pH of water due to La-based perovskites Lewis acidic properties and OH − competition under alkaline conditions. The phosphate adsorption performance is excellent under acidic conditions, and the phosphate adsorption performance usually decreases under alkaline conditions.…”