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MANGANESE DIOXIDE COATED FILTERS FOR REMOVING RADIUM FROM DRINKING WATER
Citation:
Menetrez, M., D. Anderson, AND E. Stahel. MANGANESE DIOXIDE COATED FILTERS FOR REMOVING RADIUM FROM DRINKING WATER. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-88/057.
Description:
Research was performed using manganese dioxide (MnO2) to demonstrate that above pH3 cations are adsorbed from solution in the order of their affinity, and that the interaction is characterized by the pH dependence of the metal. The relationship of the zero point charge of pH and the solution ionic strength effects on interfacial surface potential and adsorption have been addressed. Characteristics of MnO2 behavior, structure, and stability found in research investigation were reviewed. Most of the study was on the use of MnO2 coated filters for the removal of radium. A few comparison tests on radium removal with ion exchange were also made. Specifically, these tests have shown that acrylic fiber filters coated with MnO2 will remove radium from water. For a high hardness water with pH = 7.4, total radium removal was 14,200 pCi/g MnO2 before the MCL of 5 pCi/L was exceeded, and for a low hardness water with pH = 4.5, total radium removal was 5000 pCi/g MnO2 before the MCL of 5 pCi/L was exceeded. Hardness passed through the MnO2 filters with little change and therefore radium was highly preferred over hardness. A step by step process for the preparation of acrylic fiber filters coated with MnO2 was designed and operated successfully.