Removal of methylene blue from aqueous solution by nano LaFeO₃ particles

Article type: Research Article

Authors: Hashemian, Saeedeh | Monshizadeh, Majeed

Affiliations: Chemistry Department, Islamic Azad University, Yazd Branch, Yazd, Iran

Note: [] Corresponding author: Saeedeh Hashemian, Chemistry Department, Islamic Azad University, Yazd Branch, Yazd, Iran. Tel.: +98 9133514909; Fax: +98 3516240020; E-mail: [email protected]

Abstract: LaFeO3 was prepared by the sol-gel method and characterized by XRD, SEM and FT-IR. The XRD results showed that LaFeO3 is a perovskite oxide with an orthorhombic unit cell. The average crystalline size for nano crystalline LaFeO3 is 32–65 nm. Methylene blue adsorption experiments were carried out under different conditions of contact time, solution pH from 2–12 and LaFeO3 dose. The equilibrium data were fitted to Langmuir and Freundlich isotherms and the equilibrium adsorption was best described by the Langmuir isotherm model. Adsorption data were modeled using pseudo-first-order and pseudo-second order kinetics equations. The pseudo-second-order kinetic equation best described the adsorption kinetics. Thermodynamic activation parameters such as Gibbs free energy, enthalpy and entropy were calculated. The adsorption process of methylene blue on LaFeO3 was found to be spontaneous and endothermic.

Keywords: Adsorption, methylene blue, kinetics, isotherm, Perovskite–type oxide $LaFeO_{3}$

DOI: 10.3233/MGC-130094

Journal: Main Group Chemistry, vol. 12, no. 2, pp. 113-124, 2013