A new perovskite-type NdFeO3 adsorbent: synthesis, characterization, and As(V) adsorption

Minh Dai Luu, Ngoc Nhiem Dao, Duc Van Nguyen, Ngoc Chuc Pham, The Ninh Vu and Trung Dung Doan

  • ANSN Editor
Keywords: nano


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

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