Synthesis, characterization and sorption studies of nano lanthanum oxide

In this study, utilization of green synthesized nano La2O3 for adsorptive removal of Congo red from aqueous solution was investigated. Crystalline character, particle size, stability, formation and morphology of nano La2O3 were investigated from XRD, FT-IR, TG/DTG, SEM and TEM techniques. The pH impact, sorption kinetics, isotherms and thermodynamics of Congo red adsorption on La2O3 were investigated. The adsorption isotherm data gave better fit to the Freundlich isotherm model, with a maximum Congo red adsorption capacity of 185.64 mg g−1. Kinetic data correlated well with the pseudo-first-order kinetic model. Electrostatic force of attraction and H-bonding were conceived as the main adsorption mechanism. 1:1 mixture of NaOH and acetone was an effective desorption agent for desorption of nano La2O3 loaded by Congo red.