Rapid removal and mechanism investigation of low-concentration phosphate from wastewater by CuFe2O4/MIL-101(Fe) composite

Developing easily separable materials for efficient treatment of low-concentration phosphate which causes eutrophication of water bodies are full of challenges. A magnetic CuFe2O4/MIL-101(Fe) composite composed of hollow spheres CuFe2O4 and octahedrons MIL-101(Fe) was first fabricated via a facile solvothermal approach. CuFe2O4/MIL-101(Fe) (1.0 g·L−1) exhibited above 88.4% adsorption efficiency for low-concentration phosphate (5.0 mg·L−1) removal, over a wide pH ranging 2–12 at 293 K. Phosphate adsorption was a spontaneous endothermic process, in good association with Langmuir and pseudo-second-order kinetic model. The XPS and FT-IR analysis elucidated that electrostatic interaction and coordination exchange were main mechanisms. In addition, after four cycles, CuFe2O4/MIL-101(Fe) displayed 75.0% adsorption of phosphate, by treatment with external magnetic field separated and 0.1 mol·L–1 NaOH desorbed. Therefore, CuFe2O4/MIL-101(Fe) exhibited high selectivity and recycling for removing phosphate from wastewater.