Radium Removal from Water by Manganese Dioxide Adsorption and Diatomaceous Earth Filtration

摘要

The study reveals that radium adsorption onto precipitated MnO2 followed by diatomaceous earth (DE) filtration is a very effective treatment process for radium-contaminated water. Radium removals in the range of 80% to 97% were observed for performed MnO2 feed concentrations of 0.63 and 1.26 mg/L as Mn in groundwaters with hardness in the range of 100 to 245 mg/L as CaCO3. Radium removal increased slightly with increasing pH whereas it decreased slightly with increasing hardness and iron (II) concentrations. Pilot studies were performed in Lemont, IL using DE filtration on a groundwater containing 12 pCi/L226Ra and 6 pCi/L228. Radium removals for both the pilot plants ranged from 90% to 97% at a MnO2 feed concentration of 1.26 mg/L as Mn, a total hardness of 245 mg/L as CaCO3, and a pH of 6.5. The costs of water treatment by MnO2 adsorption and DE filtration were estimated at $0.71 per 1000 gal for 280,000 gpd plants and $0.47 for 1 Mgd plants.