Synthesis of SrHPO4/Fe3O4 magnetic nanocomposite and its application on Pb2+ removal from aqueous solutions

Strontium hydrogen phosphate/Fe3O4 magnetic nanocomposite (M-SrHPO4) was successfully synthesized using a facile method of solution growing and applied to immobilize lead ions (Pb2+) from acidic aqueous solutions. M-SrHPO4 was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Brunauer Emmett Teller (BET) and physical property measurement system (PPMS). The resulting M-SrHPO4 possessed desirable magnetic property (25.214 emu·g−1), which contributed to the separation of solids from solutions after the immobilization process. The equilibrium removal capacity was 1215.5 mg·g−1 for Pb2+ at PH = 4.5 within 150 min. The selective immobilization of Pb2+ was slightly affected by some competing cations such as Cr3+, Cd2+, Co2+ and Cu2+. It is revealed that the immobilization mechanism of Pb2+ was based on dissolution-precipitation theory. All of the experimental data indicated that M-SrHPO4 was promising for Pb2+ removal from acidic aqueous solutions.