A new perovskite-type NdFeO ₃ adsorbent: synthesis, characterization, and As(V) adsorption

Abstract

Nanocrystalline NdFeO3 perovskite oxide was prepared by the combustion method using polyvinyl alcohol (PVA) and corresponding metal nitrate precursors under optimum process conditions, using a solution with a pH of 2, a metal/PVA molar ratio of 1:3, and a calcination temperature of 600 °C, and was characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller nitrogen adsorption and desorption, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, laser Raman spectroscopy, and thermogravimetric and differential thermal analysis. The synthesized perovskite NdFeO3, which had an average size of 20 nm and a relatively high surface area of 20 m2 g−1, was investigated for adsorbing hazardous arsenate from aqueous solution. Arsenate adsorption by perovskite NdFeO3 is a pH-dependent process with a high adsorption capacity at pH levels between 4 and 7 and a maximum As(V) adsorption capacity of 126.58 mg g−1, higher than most arsenate adsorbents reported in the literature. Kinetic and equilibrium data of reaction under the experimental conditions are best described by a pseudo-second-order and the Langmuir isotherm equation. The values of enthalpy, Gibbs free energy and entropy changes (ΔH0 = +63.916 kJ mol−1, ΔG0 = −6.551 kJ mol−1 to −14.021 kJ mol−1 at T = 283−313 K, ΔS0 = +0.249 kJ mol−1 K−1) suggested that the reaction was endothermic, spontaneous, and took place with increasing entropy.

Simple Synthesis of NdFeO3 Nanoparticles By the Co-Precipitation Method Based on a Study of Thermal Behaviors of Fe (III) and Nd (III) Hydroxides

“…The TGA/DSC results of the precipitate containing Nd (III) are shown in Figure 2. The TGA curve shows the total weight loss (∼27%) from around 60 to ∼750 • C. Assuming that the formula of the precipitate containing Nd (III) was Nd(OH) 3 , it can consequently be stated according to Reaction (8), with a theoretical weight-loss of 13.8%:…”

“…Moreover, the nano-sized crystalline perovskite materials can be applied in several advanced technologies such as solid oxide fuel cells, catalysts, chemical sensors, and electrode materials. [8][9][10][11]. Among these applications, the NdFeO 3 nanoscale materials, known as orthorhombically distorted perovskites [12,13], have significant potential applications in As (V) adsorption [8] and the fabrication of electrical and magneto-optic devices [12][13][14][15].…”

“…Nanosized NdFeO 3 materials have been synthesized by various methods, including high-temperature ceramic fabrication [12,13,16,17], sol-gel [8,14], combustion [18], ultrasound, and co-precipitation techniques that includes octanoic acid as an organic surfactant [19,20]. However, it is challenging to create single-phase nano-crystalline NdFeO 3 particles without impurity phases such as Fe 3 O 4 , NdFe 2 O 4 , or Nd 3 Fe 5 O 12 , because many factors, including the heating temperature, retention time, pH, and stoichiometric ratio between the components, have to be well controlled [16,21].…”

Structural, 57Fe Mössbauer and XPS studies of mechanosynthesized nanocrystalline Nd0.33Eu0.67Fe1-Cr O3 particles

“…Figure 5 shows the FT-IR spectra recorded for all Nd0.33Eu0.67CrxFe1-xO3 samples to have two broad cation (M) -anion (O) vibrational bands that are characteristics of perovskite-related materials in the 800-400 cm -1 wavenumber range. These bands arise from the overlapping of the Eu/Nd-O stretching and Fe/Cr-O stretching and deformation of the FeO6 vibrational modes [30][31][32][33][34]. In the spectrum of the sample with x = 0.0 (Nd0.33Eu0.67FeO3) the first band at ⁓564 cm -1 is similar to but slightly higher than those ascribed to Fe-O in both EuFeO3 (560 cm -1 ) and NdFeO3 (550 cm -1 ) [30,33-35,].…”

The Sorption Performance of Cetyl Trimethyl Ammonium Bromide-Capped La0.9Sr0.1FeO3 Perovskite for Organic Pollutants from Industrial Processes

“…Perovskites are interesting materials because a wide range of properties can result from a large number of possible metal ion combinations that can form the perovskite structure [21,22]. Perovskites have several important applications, for example in catalysis, sensors [23][24][25], and as sorbents for water decontamination [26][27][28]. Organic dyes constitute a major source of pollution in wastewater produced from many industries, which poses a threat to the water quality and the life of living beings [29].…”