Calcium Ferrite Nanoparticles: A Simple Synthesis Approach for the Effective Disposal of Congo Red Dye from Aqueous Environments

Congo red dye is classified as a toxic chemical and can be harmful if ingested, inhaled, or in contact with the skin or eyes. It can cause irritation, allergic reactions, and skin sensitization in some individuals. Thus, in this paper, CaFe2O4 nanoparticles were produced by a simple Pechini sol-gel approach and used as an adsorbent material for the efficient disposal of Congo red dye from aqueous solutions. The maximum adsorption capacity of the CaFe2O4 towards Congo red dye is 318.47 mg/g. Furthermore, the synthesized CaFe2O4 nanoparticles exhibit an average crystal size of 24.34 nm. Scanning electron microscopy (SEM) examination showed that the CaFe2O4 nanoparticles are basically ball-like particles with a mean grain size of 540.54 nm. Moreover, transmission electron microscopy (TEM) examination showed that the CaFe2O4 sample revealed aggregated spherical particles with a mean diameter of 27.48 nm. The Energy-dispersive X-ray spectroscopy (EDS) pattern reveals that the produced CaFe2O4 nanoparticles are composed of Ca, Fe, and O elements, with an atomic ratio of 1:2:4 of these elements, respectively. The disposal of Congo red dye by the synthesized CaFe2O4 nanoparticles is chemical, spontaneous, exothermic, perfectly aligned with the pseudo-second-order kinetic model, and exhibited excellent conformity with the Langmuir equilibrium isotherm.