Removal of Various Textile Dyes Using LaMn(Fe)O3 and LaFeMn0.5O3 Nanoperovskites; RSM Optimization, Isotherms and Kinetics Studies

Abstract

Nano-perovskites of La with Mn or Fe cations were prepared by the Pechini method. The products were characterized by FT-IR, TGA/DTA, XRD, FESEM, BET, and AFM analysis. The degradation efficiency of an acidic solution of anionic, cationic and neutral azo or anthraquinone dyes was investigated in the presence of LaMn(Fe)O3 and LaFeMn0.5O3 nanoperovskites without any external reagents under dark. The results reveal that degradation efficiency follows the order of LaMnO3.125 > LaFeMn0.5O3 > LaFeO3. Compared with pure LaFeO3, the LaFeMn0.5O3 sample exhibits an enhanced adsorption capability and consequently catalytic performance. The key parameters such as catalyst type, dye initial concentration and reaction time on the degradation efficiency were optimized using response surface methodology (RSM) based on historical data design. The R2, F-value, and p-value of the fitted quadratic model were obtained 0.9822, 315.51, and smaller than 0.0001, respectively; showing the significance and adequacy of the model. The Langmuir and Freundlich isotherms were utilized to fit the experimental data. The kinetic of degradation have been investigated with the use of pseudo-first-order and -second-order models. The isotherm and kinetic results reveal that each type of dye adsorb differently and need to study separately. Finally, the proposed catalysts outperformed similar catalysts in the degradation of organic dyes.