Unveiling the Synergistic Effect of Magnetite and ZrPO₄ for Highly Selective Removal of Anionic Azo Dyes via an Ion-Exchange Process

Abstract

This work represents a facile process based on ion exchange for the efficient removal of toxic and carcinogenic anionic azo dyes from industrial effluents. Azo dyes pose significant environmental challenges due to their high solubility and stability in water bodies. For this purpose, a magnetically retrievable nanocomposite Fe 3 O 4 /ZrPO 4 (FZ) has been designed. The FZ nanocomposite, consisting of nano zirconium phosphate (ZrPO 4 ) supported on magnetite nanoparticles (Fe 3 O 4 NPs), demonstrates synergistic interaction between the ion-exchange properties of ZrPO 4 and the magnetic properties of Fe 3 O 4 , leading to improved selectivity and recyclability for the removal of anionic azo dye. Characterization of the synthesized FZ nanocomposites was carried out by using X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The removal efficiency of FZ has been verified by taking reactive azo dyes including congo red (CR), reactive blue 1 (RB-1), reactive orange 16 (RO-16), and reactive violet 5 (RV-5). The reported nanocatalyst exhibits impressive adsorption capabilities, removing around 99% for CR and RB-1, 97% for RO-16, and 78% for RV-5 within 5 min in an acidic medium. The nanocomposite's magnetic property allows efficient separation from reaction mixtures, and the ion-exchange property enables its reusability for more than 15 catalytic cycles. Further, optimization of the pH of the reaction medium resulted in faster, cost-effective, more efficient separation and regeneration of the nanocomposites. The industrial applicability of this nanocomposite has been verified by treatment with synthetic wastewater. The findings hold promise for addressing environmental concerns associated with azo dye contamination in industrial effluents.