Kinetics and Adsorption Isotherms of Amine-Functionalized Magnesium Ferrite Produced Using Sol-Gel Method for...

This study is focused on the kinetics and adsorption isotherms of amine-functionalized magnesium ferrite (MgFe₂O₄) for treating the heavy metals in wastewater. A sol-gel route was adopted to produce MgFe₂O₄ nanoparticles. The surfaces of the MgFe₂O₄ nanoparticles were functionalized using primary amine (ethanolamine). The surface morphology, phase formation, and functionality of the MgFe₂O₄ nano-adsorbents were studied using the SEM, UV-visible, FTIR, and TGA techniques. The characterized nanoparticles were tested on their ability to adsorb the Pb²⁺, Cu²⁺, and Zn²⁺ ions from the wastewater. The kinetic parameters and adsorption isotherms for the adsorption of the metal ions by the amine-functionalized MgFe₂O₄ were obtained using the pseudo-first-order, pseudo-second-order, Langmuir, and Freundlich models. The pseudo-second order and Langmuir models best described the adsorption kinetics and isotherms, implying strong chemisorption via the formation of coordinative bonds between the amine groups and metal ions. The Langmuir equation revealed the highest adsorption capacity of 0.7 mmol/g for the amine-functionalized MgFe₂O₄ nano-adsorbents. The adsorption capacity of the nanoadsorbent also changed with the calcination temperature. The MgFe₂O₄ sample, calcined at 500 °C, removed the most of the Pb²⁺ (73%), Cu²⁺ (59%), and Zn²⁺ (62%) ions from the water.