Calculation from Spectrophotometric Data of Binding Parameters of Magnetic Iron Oxide Nanoparticles with Dyes

The possibility of using magnetic nanoparticles as an adsorbent for the effective removal of anionic dyes from aqueous solutions was investigated. The binding of eosin, tartrazine, and fast green with superparamagnetic Fe3O4 nanoparticles was studied using visible spectroscopy. The binding constant and site were obtained from spectrophotometric titration data using the Langmuir model for equilibrium binding. The high binding constants (~105 M–1) indicated that the magnetic nanoparticles held promise for removing anionic dyes from polluted waters.