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REMOVING BARIUM AND RADIUM THROUGH CALCIUM CATION EXCHANGE
Citation:
Myers, A., V. Snoeyink, AND D. Snyder. REMOVING BARIUM AND RADIUM THROUGH CALCIUM CATION EXCHANGE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-85/070.
Description:
The removal of barium (Ba) and radium (Ra), which are found in many groundwater sources, was achieved in laboratory studies with an ion exchange process. In the studies, a strong acid resin in the calcium form effectively removed Ba(+2) and Ra (+2) to meet standards. The resin was regenerated with reclaimed brine, which would reduce disposal problems in actual practice. Total hardness, alkalinity, pH, and other water quality parameters remained unchanged. Additional research is needed, however, to refine the process and establish the costs. The process uses a calcium (Ca)-form strong acid ion exchange resin column in parallel with a conventional sodium (Na)-form strong acid resin column. The divalent Ra(+2), Ba(+2), Ca(+2), and magnesium (Mg)+2) ions are exchanged for Na(+1) in the portion of the flow that passes through the Na-form column. If present, Ba(+2) and Ra(+2) are exchanged for Ca(+2) in the fraction of water passing through the Ca-form column, and the total hardness in this fraction is essentially unchanged. Calcium chloride brine (CaCl(+2)) is used to regenerate the Ca-form column, and the spent brine can be reused after precipitating and removing the Ba and Ra.