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Ind. Eng. Chem. Res. 2000, 39, 3034-3037
Kinetics and Isotherms for Aqueous Lead Adsorption by Natural Minerals M. Prasad,* S. Saxena, S. S. Amritphale, and Navin Chandra Regional Research Laboratory (C.S.I.R.), Hoshangabad Road, Near Habibganj Naka, BHOPAL 462 026, India
The low grade (30% P2O5) rock phosphates have also been utilized2 for the removal of different heavy metal ions from aqueous solutions and have been found to be effective in the separation of lead ranging from 38.8 to 100%, depending on its initial concentration. In recent years, clays and related minerals (such as pyrophyllite) have also been explored as sorbents not only for organic species7-9 but also for heavy metal ions.10-13 The severe limitation of these processes, however, lies in the high cost of the substrate material and difficulty in regeneration/recyclability. The high grade rock phosphates already find major applications in phosphoric acid and fertilizer manufacture. Hydroxyapatite is too costly to be commercially used. However, the low grade (
