Magnetic MnFe2O4/ZnFe-LDH for Enhanced Phosphate and Cr (VI) Removal from Water.

Due to the layered structure and recycling characteristics, magnetic MnFe2O4/ZnFe-LDH was prepared by co-precipitation. In this study, we intensively explored MnFe2O4/ZnFe-LDH for water purification compared with the ZnFe-LDH. The morphological and structural characteristics of the obtained products were systematically characterized. MnFe2O4/ZnFe-LDH exhibits the maximum adsorption capacity of 94.52 mg/g for phosphate and 49.03 mg/g for Cr (VI), respectively, which is superior to that of the ZnFe-LDH, indicating that the magnetic MnFe2O4 effectively enhanced adsorption performance. Meanwhile, the mechanism of adsorption of phosphate and Cr (VI) was briefly studied, where the metal center ion in MnFe2O4/ZnFe-LDH and between layers of SO42- serves as capture sites for phosphate and Cr (VI) removal. Furthermore, the MnFe2O4/ZnFe-LDH can be used for magnetic recycled and still maintained excellent removal efficiency (70%) for phosphate and Cr (VI) after five adsorption-desorption cycles. This work could open a new vista of designing magnetic novel adsorbents in environmental remediation.