Germany Journal

Document Type : Original Article

Authors

Department of Chemistry, Semnan University, Semnan, 35195-363, Iran.

Abstract

Background and purpose:  In this study, LaMnO3 nanoparticles were used as a suitable adsorbent for malachite green (MG) removal from aqueous solutions. Adsorption values were investigated by changing the parameters of contact time, pH, temperature, adsorbent dosage, and initial dye concentration. The isotherm of Langmuir, Freundlich, Dubinin-Radushkevich, and Tempkin were studied. The sequels showed that the MG adsorption process follows the Langmuir and Freundlich isotherms. Maximum adsorption capacity was 27.027 mg.g-1 for 0.007 g of LaMnO3. Various kinetic models were used to describe the kinetic data and the first kinetic model was consistent with the results. The thermodynamic parameters of the LaMnO3 adsorption process such as Gibbs free energy (ΔG0), standard enthalpy change (ΔH0) and standard entropy change (ΔS0) were calculated. 
Materials and Methods:  All the chemicals were analytical grade and were used without further purification. For LaMnO3, the following materials were used: H2O, La (NO3)3, MnCl2, KMnO4 and prepared via hydrothermal method. The synthesized adsorbent was detected by FTIR, XRD, FESEM, and TEM analyze.
Results:  The resultants showed that due to the negative Gibbs free energy and the positive integrity of the enthalpy, the process is spontaneous and endothermic.
Conclusion:  The adsorbent performance of removing dyes from the aqueous medium has shown that it can be used as an effective and inexpensive adsorbent in the process of treating a variety of colored sewage.

Keywords