Simple Synthesis and Characterization of Cobalt Ferrite Nanoparticles for the Successful Adsorption of Indigo Carmine Dye from Aqueous Media

Indigo carmine dye falls into the category of toxic chemicals, potentially leading to irritation and allergic reactions in certain individuals. Thus, this study employed the Pechini sol-gel strategy to easily produce CoFe2O4 nanoparticles, which serve as an effective adsorbent for the disposal of indigo carmine dye from aqueous solutions. The maximum adsorption capacity of CoFe2O4 for indigo carmine dye was determined to be 421.94 mg/g. The synthesized CoFe2O4 nanoparticles exhibited an average crystallite size of 18.75 nm. SEM analysis revealed that these nanoparticles were nearly spherical, with an average grain size of 198.32 nm. Additionally, TEM analysis indicated a fully agglomerated spherical morphology for the CoFe2O4 sample, with an average diameter of 15.37 nm. The EDS spectrum confirmed that the synthesized CoFe2O4 nanoparticles consisted of Co, Fe, and O elements, with respective weight percentages of 17.82%, 49.46%, and 32.72%. The removal of indigo carmine dye by the synthesized CoFe2O4 is spontaneous, chemical, exothermic, closely fitting the pseudo-second-order kinetic model, and demonstrating a strong concordance with the Langmuir equilibrium isotherm.