Hydrothermal synthesis of LaFeO₃ nanoparticles adsorbent: Characterization and application of error functions for...

The adsorption of fluoride from aqueous solution by lanthanum ferrite nanoparticles (LaFeO₃ NPs) synthesized by the hydrothermal method has been investigated. This experimental study was conducted on a laboratory scale. The effects of various operating parameters such as pH (3-11), LaFeO₃ NPs dosage (0.1-1.0 g/L), contact time (15-120 min), temperature (303-318 K), and initial concentration of fluoride (15-40 mg/L) on fluoride adsorption were studied. The results showed that under optimal conditions of fluoride concentration of 20 mg/L, pH of 5, LaFeO₃ NPs dosage of 0.9 g/L, temperature of 308 K, and contact time of 60 min, maximum percentage removal of 94.75 % was obtained. The process of fluoride adsorption on LaFeO₃ NPs was found to depend on the Freundlich adsorption and Koble-Corrigan isotherm models. The monolayer adsorption capacity of LaFeO₃ NPs was 2.575 mg/g. The kinetic data fitted best into the pseudo-second-order model considering the values of the regression coefficients (r²) and error functions used. The thermodynamics study indicated that the adsorption process was exothermic (ΔH°< 0) and spontaneous (ΔG°< 0) in nature. It could be concluded that the synthesized LaFeO₃NPs can be used as an effective adsorbent for fluoride ions removal from aqueous solutions.