Iris barnumiae extract-coated Fe3O4 nanoparticles for the removal of Congo red dye in aqueous solution

In this work, coated Fe3O4 nanoparticles were prepared using Iris barnumiae extract. The coated Fe3O4 nanoparticles were characterised using FESEM, FT-IR, and BET techniques. The coated Fe3O4 nanoparticles were applied as an adsorbent for the removal of Congo red in an aqueous solution at 25 degrees C while varying time, pH level, and dosage of adsorbent. The coated Fe3O4 nanoparticles demonstrated high efficiency for the removal of Congo red in an aqueous solution under the following conditions: time, 60 min; pH 2; dosage, 0.02 g. We also determined that the Langmuir isotherm model is a better model for describing the adsorption of Congo red onto coated Fe3O4 nanoparticles than the Freundlich isotherm model. The maximum Congo red adsorption capacity for coated Fe3O4 nanoparticles at 25 degrees C was determined to be 50 mg/g. Thermodynamic analysis of the adsorption of Congo red onto coated Fe3O4 nanoparticles revealed the process to be spontaneous. Kinetic studies of the adsorption of Congo red onto coated Fe3O4 nanoparticles were performed, where in the data demonstrated a good fit with the pseudo-second-order model, revealing that the adsorption capacity conformed to a second-order kinetic model.