Phosphate removal from river water using a highly efficient magnetically recyclable Fe3O4/La(OH)3 nanocomposite

Abstract

Lanthanum based nanocomposites have attracted much attention for their efficiency and capacity in removing phosphate from water. This study developed a Fe3O4/La(OH)3 nanocomposite through a precipitation route at room temperature and used the nanocomposite to remove phosphate from river water. Performance of the Fe3O4/La(OH)3 nanocomposite was evaluated in terms of sorption kinetics, sorption isotherms, different solution pH values, competing ions, and regenerative ability. The Fe3O4/La(OH)3 nanocomposite showed a nanosphere-like morphology with 97% magnetic separation efficiency, excellent phosphate removal capacity of 253.83 mg/g, 99% phosphate selectivity in the presence of chloride, nitrate, sulfate, fluoride, and calcium as competing ions and excellent reusability in ten cycles. Based on these findings, the Fe3O4/La(OH)3 nanocomposite was used to remove phosphate from river water. It was found that, in 60 min, a 0.1 g/L dosage of the nanocomposite was able to reduce the phosphate in the water from 0.087 mg/L to 0.002 mg/L. Moreover, studying of the removal mechanism of the nanocomposite revealed that surface complexation and the electrostatic interaction between phosphate species and lanthanum hydroxide played a prominent role in the sorption of phosphate.