Efficient removal of fluoride from aqueous solutions using 3D flower-like hierarchical zinc-magnesium-aluminum ternary oxide microspheres

Herein, novel 3D hierarchical flower-like zinc-magnesium-aluminum ternary metal oxide (CZMA) microspheres were successfully prepared for the first time by a simple-green hydrothermal strategy without any surfactant or template combined with a calcination process and were employed as an adsorbent for adsorptive removal of excess fluoride. The adsorbent was characterized by diverse microscopic, spectroscopic, diffractometric, and thermal analysis techniques. The flower-like microspheres with a mean diameter of 8.74 mu m were assembled by nanosheets with thicknesses of approximately 100 nm. The adsorption property for fluoride on the ZMA and the CZMA were analyzed by batch experiments. The results showed that the fluoride uptake behavior of the samples could precisely be fitted by the Langmuir isothermal model and the maximum adsorption capacity reached up to 84.24 mg/g at 298 K under neutral conditions. The pseudo-second-order model accurately described the adsorption kinetics data. Moreover, the regeneration experiment revealed that the samples have excellent reusability. XPS, FT-IR and zeta potential results indicated that the underlying fluoride adsorption mechanism of the samples can be ascribed to ion exchange and electrostatic interactions. Real water tests demonstrated that the CZMA is an efficient and rapid adsorbent candidate for water purification in environmental remediation.