Evaluation of organic and inorganic adsorbents for the removal of uranium and plutonium from process streams

Mound Laboratory is evaluating macroporous, ion exchange resins for the removal of plutonium, uranium, and various colloids from process waste treatment effluents. A number of organic ion exchange resins were evaluated for removal of 238Pu(IV), 238Pu(VI), and 233U(VI) from water using batch isotherm tests. The capacity and equilibrium distribution coefficients were compared with each other and with bone char, an inorganic adsorbent consisting of hydroxyapatite (HAP). The various types of adsorbents showed that the extent of removal and the equilibrium coefficients (K/sub d/) were functions of pH. For removal of polymeric plutonium, 238Pu(IV), the best results were achieved using the inorganic adsorbent, bone char (hydroxyapatite), at pH 7. However, macroporous, weak base, anion exchange resins also showed reasonable K/sub d/ values at pH 7. The best removal of polymeric plutonium can be achieved using chemisorption or weak base anionic exchange, indicating strongly ionized anions. Excellent results for removal of 238Pu(VI) were achieved using macroporous, strong base, anion exchange resins and macroporous, strong acid, cation exchange resins. For removal of ionic 233U(VI), the strongly acidic cation exchangers gave the better results; the K/sub d/ values were on the order of 102 better than bone char. Again, performance was strongly dependent upon pH. Adsorbent resins which remove constituents by physical adsorption did not perform well for uranium removal