4Petrovie M,Kastelan M, Horvat A J M. Interactive sorp- tion of metal ions and hunic acids onto particles[J3. Water Air and Soil Pollution, 1998,12:41-45.
5XU Yu-ping. Sorption of Zn and Cd on hydroxyapatite surfaceEJ3. Environ Sci Technol, 1994,28 : 1427-1480.