Economic and Environmental Geology (자원환경지질)

The Korean Society of Economic and Environmental Geology (대한자원환경지질학회)
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Optimum Condition of Soil Dispersion for Remediating Heavy Metal-Contaminated Soils using Wet Magnetic Separation

중금속 오염 토양 정화를 위한 습식자력선별법 사용 시 최적 토양분산 조건

  • Chon, Chul-Min (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Park, Jeong-Sik (Korea Mine Reclamation Corporation) ;
  • Park, Sook-Hyun (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Jae-Gon (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Nam, In-Hyun (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources)
  • 전철민 (한국지질자원연구원 지구환경연구본부) ;
  • 박정식 (한국광해관리공단) ;
  • 박숙현 (한국지질자원연구원 지구환경연구본부) ;
  • 김재곤 (한국지질자원연구원 지구환경연구본부) ;
  • 남인현 (한국지질자원연구원 지구환경연구본부)
  • Received : 2012.03.10
  • Accepted : 2012.04.24
  • Published : 2012.04.28
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Abstract

Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.

본 연구에서는 자력선별 토양정화기술 공정에 적합한 토양의 최적 분산 조건을 도출하기 위하여 토성이 다른 중금속 오염토양 2종의 시료(US, JIK)를 대상으로 분산특성 및 중금속 용출 특성을 파악하였다. 분산제로는 인산염(pyrophosphate, hexametaphosphate, orthophosphate), 계면활성제(sodium dodecyl sulfate, SDS)가 사용되었으며, pH = 9~12와 농도변화(1~200 mM)에 따른 토양입단의 분산특성 및 중금속 함량을 파악하고, 효율적인 분산조건을 도출하였다. 분산용액의 pH변화에 따른 토양분산 특성은 입도변화 결과를 통하여 파악할 수 있는데, 분산용액의 pH가 12에 가까워질수록 현탁액의 점토함량이 증가하였다. 이는 pH가 상승함에 따라 PZC(point of zero charge)이상의 pH가 유지되면서 점토입자들이 분산된 상태로 유지된 것으로 여겨진다. 농도변화에 따른 토양분산 실험 결과, 농도가 증가함에 따라서 높은 점토함량을 나타내었는데, 이는 산화철, 산화망간의 PZC보다 높은 분산용액의 pH조건과 분산제의 흡착에 기인한 것으로 판단된다. 토양입자의 분산에 따른 중금속 용출은 pyrophosphate, hexametaphosphate, orthophosphate는 50 mM 이상의 농도에서, SDS의 경우 100 mM이상의 농도에서 비소 용출량이 일정하게 나타났다. 또한, 분산용액의 pH가 증가함에 따라 비소 용출량도 증가하였다. 인산염은 비소와 유사한 화학구조를 지니고 있어 토양입자표면에서 흡착경쟁을 하여 비소의 탈착을 유발하고, 계면활성제는 토양입자표면에 흡착하여 비소가 탈착되는 것으로 파악된다. 분산용액에 따른 분산효과는 pyrophosphate > hexametaphosphate > SDS > orthophosphate의 순으로 나타났다. 결과적으로 분산효율 및 비소용출량을 고려한 최적의 토양분산용액 조건은 pH 11, 10 mM pyrophosphate로 판단된다. 이러한 결과들은 고구배 자력선별 기술을 이용한 토양정화 공정을 최적화하는데 활용될 수 있을 것으로 기대된다.

Keywords

References

  1. Alhammadi, M.S. and Miller, D.M. (2006) Effect of ionic strength and sodium adsorption ratio on the flocculation/ dispersion of two surface soils from eastern arkansas. Soil Science, v.171, p.960-967. https://doi.org/10.1097/01.ss.0000227578.89446.1f
  2. Arduino, E., Barberis, E. and Boero, V. (1989) Iron oxides and particle aggregation in B horizons of some Italian soils. Geoderma, v.45, p.319-329 https://doi.org/10.1016/0016-7061(89)90014-1
  3. Bartoli, F., Burtin, G. and Herbillon, A.J. (1991) Disaggregation and clay dispersion of oxisols: Na resin, a recommended methodology. Geoderma, v.49, p.301-317. https://doi.org/10.1016/0016-7061(91)90082-5
  4. Bradl, H.B. (2004) Adsorption of heavy metal ions on soils and soils constituents. Journal of Colloid and Interface Science, v.277, p.1-18. https://doi.org/10.1016/j.jcis.2004.04.005
  5. Bronick, C.J. and Lal R. (2005) Soil structure and management: a review. Geoderma, v.124, p.3-22. https://doi.org/10.1016/j.geoderma.2004.03.005
  6. Chon, C.-H., Park, J.S., Kim, J.G. and Lee, Y.S. (2010) Relationship between physicochemical properties, heavy metal contents and magnetic susceptibility of soils. Jourmal of the Mineralogical Society of Korea, v.23, p.281-295.
  7. Chon, C.-M., Kim, J.G., Lee, G.H. and Kim, T.H. (2008) Influence of extractable soil manganese on oxidation capacity of different soils in Korea. Environmental Geology, v.55, p.763-773. https://doi.org/10.1007/s00254-007-1029-7
  8. Colombo, C. and Torrent, J. (1991) Relationships between aggregation and iron oxides in terra rossa soils from southern Italy. Catena, v.18, p.51-59. https://doi.org/10.1016/0341-8162(91)90006-J
  9. Castellini, E., Lusvardi, G., Malavasi, G. and Menabue, L. (2005) Thermodynamic aspects of the adsorption of hexametaphosphate on kaolinite. J. Colloid Interface Sci., v.15, p.322-329.
  10. Gunister, E., Isci, S., Alemdar, A. and Gungor, N. (2004) Effect of sodium dodecyl sulfate on flow and electrokinetic properties of Na-activated bentonite dispersions. Bull. Mater. Sci., v.27, p.317-322. https://doi.org/10.1007/BF02708522
  11. Hazel, F. (1942) The effect of small concentrations of hexametaphosphate on iron oxide surfaces. Journal of Physical Chemistry, v.46, p.516-524 https://doi.org/10.1021/j150418a011
  12. Jackson, M.L. (1956) Soil chemical analysis-advanced course. Pub. by the author, Dept. of Soils, Univ. of Wisconsin, Madison, WI, USA.
  13. Jang, M., Hwang, J.S. and Choi, S.I. (2007) Sequential soil washing techniques using hydrochloric acid and sodium hydroxide for remediating arsenic-contaminated soils in abandoned iron-ore mines. Chemosphere, v.66, p.8-17. https://doi.org/10.1016/j.chemosphere.2006.05.056
  14. Kim, K.H., Kim, K.Y., Kim, J.G., Sa, T.M., Suh, J.S., Sohn, B.K., Yang, J.E., Eom, K.C., Lee, S.E., Jung, K.Y., Chung, D.Y., Jeong, Y.T., Chung, J.B. and Hyun, H.N. (2006) Soil Science. Hyangmunsa, 471p.
  15. Lagaly, G. (1989) Principles of flow of kaolin and bentonite dispersions. Applied Clay Science, v.4, p.105-123. https://doi.org/10.1016/0169-1317(89)90003-3
  16. Lee, S.E., Hong, C.W., Kim, Y.H., Park, C.W., Seo, M.C., Ok, Y.S., Zhang, Y.S., Jung, W.K., Jeong, C.Y., Hyun, S.H. and Hong, S.G. (2006) Soil chemistry. Korea J. Soil Sci. Fert., v.42, p.53-101.
  17. Mehra, O.P. and Jackson, M.L. (1960) Iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate. Clays Clay Miner. v.7, p.317-327.
  18. Ministry of Environment (2002) Report of detailed survey for soil contamination. Korea.
  19. Nguyen, M. N., Dultz, S., Kasbohm, J. and Le, D. (2009) Clay dispersion and its relation to surface charge in a paddy soil of the red river delta, Vietnam. J. Plant Nutr. Soil Sci., v.172, p.477-486. https://doi.org/10.1002/jpln.200700217
  20. NIAST (2005) Establishment of operating system for agricultural and environmental information network. National Institute of Agricultural Science and Technology, RDA, Suwon, Korea.
  21. NIAST (2007) Methods of soil chemical analysis. National Institute of Agricultural Science and Technology, RDA, Suwon, Korea.
  22. Pinheiro-Dick, D. and Schwertmann, U. (1996) Microaggregates from oxisols and Inceptisols: dispersion through selective dissolutions and physicochemical treatments. Geoderma, v.74, p.49-63. https://doi.org/10.1016/S0016-7061(96)00047-X
  23. Schott, H. and Kazella, I. J. (1967) Interaction of an anionic surfactant with hydrous ferric oxide sol. Journal of the American Oil Chemists Society, v.44, p.416- 419. https://doi.org/10.1007/BF02666782
  24. Sparks, D.L. (2003) Environmental soil chemistry. Elsevier Science, California, 370p.
  25. Subramaniam, K., Vithayaveroj, V., Yiacoumi, S. and Tsouris C. (2003) Copper uptake by silica and iron oxide under high surface coverage conditions: surface charge and sorption equilibrium modeling. Journal of Colloid and Interface Science, v.268, p.12-22. https://doi.org/10.1016/j.jcis.2003.07.012
  26. Teo, J., Liew, W.K., and Leong, Y.K. (2009) Clay, phosphate adsorption, dispersion, and rheology. Water Air Soil Pollut, v.9, p.403-407. https://doi.org/10.1007/s11267-009-9229-7
  27. Ward, P.A.III. and Carter, B.J. (2004) Dispersion of saline and non-saline natric mollisols and alfisols. Soil Science, v.169, p.554-566. https://doi.org/10.1097/01.ss.0000138415.92050.95