Issue
Korean Journal of Chemical Engineering,
Vol.21, No.2, 419-424, 2004
Adsorption Behavior of Aqueous Europium on Kaolinite under Various Disposal Conditions
This work investigated the adsorption behavior of europium on kaolinite under various disposal conditions. Batch-wise adsorption and precipitation experiments and equilibrium model calculations were performed over a pH range of 4-10 and CO2 concentration range of 0%, 0.03%, and 10%. Experimental precipitation behaviors are in agreement with the results of equilibrium model calculations using the geochemical code MINTEQA2. Aqueous species of Eu3+ exists mainly at pH 5 or below and solid phases of Eu(OH)3(s), Eu(OH)CO3(s), and Eu2(CO3)3·3H2O(s) are formed at higher pH ranges. Adsorption behavior of Eu on kaolinite in the low pH range can be explained by interlayer ion-exchange reaction. The significant increase in adsorbed amount at pH 5-6 is due to the surface complexation at the edge site of kaolinite. In the high pH range, precipitation of Eu contributes mainly to the adsorption quantity. The rapid decrease in adsorbed amount above pH 7 under 10% CO2 condition occurs by the formation of anionic europium species of Eu(CO3)-2. The adsorption of Eu on kaolinite could be well interpreted by the Freundlich adsorption isotherm. The data except for the highest equilibrium concentration ranges were also explained by Langmuir isotherm and the maximum adsorbed quantity of Eu on kaolinite, b, is 1.2 mg/g.
[References]
  1. Allison JD, Brown DS, Novo-Gradac KJ, "MINTEQA2/PRODEFA2, A Geochemical Assessment Model for Environmental Systems: Version 3.0 User's Manual," EPA/600/3-91/021, U.S. EPA, 1991
  2. Bodek I, Lyman WJ, Reehl WF, Rosenblatt DH, "Environmental Inorganic Chemistry: Properties, Processes, and Estimation Methods," Pergamon Press, 1988
  3. Choppin GR, Pizkalla EN, "Handbook of the Physics and Chemistry of Rare Earths," Gshneidner, K.A., Jr. and Eyring, L., eds., North-Holland, Publ., 1994
  4. Dzombak DA, Morel FMM, "Surface Complexation Modeling: Hydrous Ferric Oxide," John Wiley & Sons, 1990
  5. Hyun SP, Cho YH, Kim SJ, Hahn PS, J. Colloid Interface Sci., 222(2), 254, 2000
  6. Jung J, Cho YH, Hahn PS, Bull. Korean Chem. Soc., 19, 3, 1998
  7. Kang MJ, Han BE, Hahn PS, Environ. Eng. Res., 7(3), 149, 2002
  8. Kim JI, "Chemical Behavior of Transuranic Elements in Natural Aquatic Systems, Handbook on the Physics and Chemistry of the Actinides," Freeman, A.J. and Keller, C., eds., Elsevier Science Publishers, B.V., 1986
  9. Kim SJ, Kim TY, Kim SJ, Cho SY, Korean J. Chem. Eng., 19(6), 1050, 2002
  10. Kohler M, Honeyman BD, Leckie JO, Radiochim. Acta, 85, 33, 1999
  11. Lee DK, Kim HT, Kang MJ, Hahn PS, Chun KS, HWAHAK KONGHAK, 38(5), 753, 2000
  12. Ledin A, Karlsson S, Duker A, Allard B, Radiochim. Acta, 66-67, 213, 1994
  13. Lieser KH, Radiochim. Acta, 70-71, 355, 1995
  14. Ma C, Eggleton RA, Clays Clay Miner., 47(2), 174, 1999
  15. Nitsche H, Radiochim. Acta, 52-53, 3, 1991
  16. Park CK, Ryu BH, Hahn PS, Korean J. Chem. Eng., 19(5), 765, 2002
  17. Patrick VB, Randall TC, Kathryn LN, "Surface Charge and Metal Sorption to Kaolinite, Adsorption of Metals by Geomedia," Academic Press, 1998
  18. Silva RJ, Nitsche H, Radiochim. Acta, 70-71, 377, 1995
  19. Spahiu K, Bruno J, "A Selected Thermodynamic Database for REE to Be Used in HLNW Performance Assessment Exercises," SKB TR 95-35, 1995
  20. Sposito G, "The Chemistry of Soils," Oxford Univ., Press, 1989
  21. Stumn W, "Part 1. The Solid-Solution Interface, Aquatic Surface Chemistry," John Wiley & Sons, 1987
  22. Stumn W, "Chemistry of the Solid-Water Interface: Processes at the Mineral-Water and Particle-Water Interface in Natural Systems," John Wiley & Sons, 1992
  23. Stumm W, Morgan JJ, "Aquatic Surface Chemistry: Chemical Equilibria and Rates in Natural Waters," John Wiley & Sons, 1996
  24. vanOlphen H, "Chap. 5 Clay Mineralogy, An Introduction to Clay Colloid Chemistry," John Wiley & Sons, 1977