Magnetic Separation of Phosphate and Heavy Metal Ions Using Ferrimagnetic Particles for Water Purification

• Published in: Journal of Japan Society on Water Environment Vol. 25; no. 1; pp. 33 - 38
• Main Authors: GOKON, Nobuyuki, SHIMADA, Ayano, MATSUOKA, Takahito, KANEKO, Hiroshi, TAMAURA, Yutaka, OHARA, Takeshi
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Society on Water Environment 01.01.2002
• Subjects: ferrimagnetic fine particles; magnetic coagulation; magnetic separation; phosphate and heavy metal ions removal
• ISSN: 0916-8958; 1881-3690
• DOI: 10.2965/jswe.25.33

To develop a practical environmental protection technology for purification of lakes, ponds and arm of the sea, an efficient magnetic separation system for phosphate and heavy metal ions removal was studied using ferrimagnetic fine particles (FMFP), which can be prepared from Fe2+ and Fe3+ ions in the alkali aqueous solution. With the Fe3+ ions of 15 mg·l-1 (without addition of FMFP), the phosphate ion recovery decreased from 80% to 20% with decreasing the magnetic field from H=8T to 0.8T. By addition of the FMFP of 5 mg·l-1 along with the Fe3+ ions of 15 mg·l-1, above 95% recovery was achieved in a wide range of the magnitude of magnetic field (H=0.8-8T). In case of using cadmium ion instead of the phosphate ion, addition of the FMFP of 5 mg·l-1 together with the Fe3+ ions of 20 mg·l-1 enhanced recovery of the Cd2+ ion. We demonstrated that in the presence of the FMFP all of the heavy metal ions were recovered 80% yields or more. These would come from a high magnetic gradient characteristically generated on the surface of FMFP, which results in the enhancement of the magnetic coagulation of the complex with the phosphate or the heavy metal ions and the Fe3+ ions.