Role of Electrode Reaction of Electrolyte in Electrokinetic-Fenton Process for Phenanthrene Removal

동전기-펜턴 공정에서 전해질의 전극반응이 처리효율에 미치는 영향

  • Park Ji-Yeon (Korea Institute of Energy Research) ;
  • Kim Sang-Joon (Department of Chemical & Biomolecular Engineering, KAIST) ;
  • Lee You-Jin (Department of Chemical & Biomolecular Engineering, KAIST) ;
  • Yang Ji-Won (Department of Chemical & Biomolecular Engineering, KAIST)
  • 박지연 (한국에너지기술연구원) ;
  • 김상준 (한국과학기술원 생명화학공학과) ;
  • 이유진 (한국과학기술원 생명화학공학과) ;
  • 양지원 (한국과학기술원 생명화학공학과)
  • Published : 2006.02.01

Abstract

The effects of electrolytes were investigated on the removal efficiency when several different electrolytes were used to change the electrode reaction in an electrokinetic (EK)-Fenton process to remediate phenanthrene-contaminated soil. Electrical potential gradient decreased initially due to the ion entrance into soil and then increased due to the ion extraction from soil under the electric field. Accumulated electroosmotic flow was $NaCl>KH_2PO_4>MgSO_4$ at the same concentration because the ionic strength of $MgSO_4$ was the highest and $Mg(OH)_2$ formed near the cathode reservoir plugged up soil pore to inhibit water flow. When hydrogen peroxide was contained in electrolyte solution, removal efficiency increased by Fenton reaction. When NaCl was used as an electrolyte compound, chlorine ($Cl_2$) was generated at the anode and dissolved to form hypochlorous acid (HClO), which increased phenanthrene removal. Therefore, the electrode reaction of electrolyte in the anode reservoir as well as its transport into soil should be considered to improve removal efficiency of EK-Fenton process.

Phenanthrene 오염토양 정화를 위한 동전기-펜턴 공정에서, 전해질의 종류와 전극반응에 따른 전기삼투유량의 변화와 오염물의 분해율을 관찰하였다. 전압경사는 초기에 감소하였다가 다시 증가하였는데, 이는 전류가 공급됨에 따라 이 온이 토양 내로 유입되어 전도도가 증가하였다가, 전기삼투 및 전기이동 현상에 의해 이온이 유출수를 통하여 빠져 나가 토양 내의 이온 농도가 다시 감소하여 전도도가 감소하였기 때문이다 총 전기삼투유량은 $NaCl>KH_2PO_4>MgSO_4$의 순서로 나타났는데, 이는 같은 몰농도(M)에서 $MgSO_4$의 이온세기가 다른 전해질보다 높았기 때문이다. 과산화수소를 첨가했을 경우는, 첨가하지 않은 경우보다 펜턴 반응에 의한 산화분해로 제거율이 향상되었다. NaCl의 경우, 양극 전극조에서 전극 반응에 의해 생성된 염소 가스($Cl_2$)가 산성조건에서 용해되어 형성된 하이포아염소산 (HClO)이 오염물의 산화분해를 증가시켜 다른 전해질보다 높은 제거율을 나타내었다. 따라서 동전기-펜턴 공정에서 제거율을 향상시키기 위해서는, 전해질이 토양 내에서 동전기적 이동 메커니즘에 미치는 영향과 더불어 양극 전극조에서의 전극 반응에 의한 생성물의 특성 또한 고려되어야 한다.

Keywords

References

  1. 박지연, 김상준, 이유진, 양지원, 2004, 3차원 토양 실험장치에서 phenanthrene 오염토양 정화를 위한 동전기-펜턴 공정, J. of KSEE, 26(6), 697-702
  2. 양운진, 1991, 수질화학, 신광문화사, 서울, 69-157
  3. 염익태, Ghosh, M.M., 안규홍, 1997, 계면활성제를 이용한 오염된 토양으로부터의 Polycyclic Aromatic Hydrocarbon(PAH)의 세척, J. of KSEE, 19(9), 1111-1124
  4. 이현호, 백기태, 양지원, 1999, 동전기 정화기술을 이용한 kaolinite-white O에서의 납 제거, J. of KSEE, 21(9), 1751-1760
  5. Acar, Y.B. and Alshawabkeh, A.N., 1993, Principles of electrokinetic remediation, Environ. Sci. Technol., 27(13), 2638-2647 https://doi.org/10.1021/es00049a002
  6. Acar, Y.B., Gale, R.J., Alshawabkeh, A.N., and Marks, R.E., 1995, Electrokinetic remediation: Basics and technology status, J. of Hazardous Materials, 40, 117-137 https://doi.org/10.1016/0304-3894(94)00066-P
  7. Acar, Y.B., Gale, R.J., Putnam, G.A., Hamed, J., Wong, R.L., 1990, Electrochemical processing of soils: Theory of pH gradient development by diffusion, migration, and linear convection, J. of Environ. Sci. Health, A25(6), 687-714
  8. Hamed, J., Acar, Y.B., Gale, R.J., 1991, Pb(II) removal from kaolinite by electrokinetics, J. of Geotech. Eng., 117(2), 241-271 https://doi.org/10.1061/(ASCE)0733-9410(1991)117:2(241)
  9. Ho, S.V., Athmer, C., Sheridan, P.W., Hughes, B.M., Orth, R., 1999, The Lasagna technology for in situ soil remediation. 1. Small field test, Environ. Sci. Technol, 33, 1086-1091 https://doi.org/10.1021/es980332s
  10. Ho, S.V., Athmer, C., Sheridan, P.W., Hughes, B.M., Orth, R., 1999, The Lasagna technology for in situ soil remediation. 2. Large field test, Environ. Sci. Technol, 33, 1092-1099 https://doi.org/10.1021/es980414g
  11. Ko, S.O., Schlautman, M.A., and Carraway, E.R., 2000, Cyclodextrin-enhanced electrokinetic removal of phenanthrene from a model clay soil, Environ. Sci. Technol., 34, 1535-1541 https://doi.org/10.1021/es990223t
  12. Lageman, R., 1993, Electroreclamation, Environ. Sci. Technol., 27(13), 2648-2650 https://doi.org/10.1021/es00049a003
  13. Lee, H.H. and Yang, J.W., 2000, A new methode to control electrolytes pH by circulation system in electrokinetic soil remediation, J. of Hazardous Materials, B77, 227-240
  14. Shapiro, A.P., Renaud, P.C., and Probstein, R.F., 1989, Preliminary studies on the removal of chemical species from saturated porous media by electroosmosis, Physicochemical Hydrodynamics, 11(5), 785-802
  15. Stoner, G.E. and Cahen, G.L., 1982, The mechanism of low frequency a.c. electrochemical disinfection, Bioelectrochemistry and Bioenergetics, 9, 229-243 https://doi.org/10.1016/0302-4598(82)80013-5
  16. Szpyrkowicz, L., Juzzolino, C., and Kaul, S.N., 2001, A comparative study on oxidation of dispersed dyes by electrochemical process, ozone, hypochlorite and Fenton reagent, Wat. Res., 35(9), 2129-2136 https://doi.org/10.1016/S0043-1354(00)00487-5
  17. Szymczyk, A., Fievet, P., Mullet, M., Reggiani, J.C., and Pagetti, J., 1998, Comparison of two electrokinetic methods-electroosmosis and streaming potential-to determine the zeta-potential of plane ceramic membranes, J. of Membrane Science, 143, 189-195
  18. Teel, A.L., Warberg, C.R., Atkinson, D.A., and Watts, R.J., 2001, Comparison of mineral and soluble iron Fenton's catalysts for the treatment of trichloroethylene, War. Res., 35(4), 977-984 https://doi.org/10.1016/S0043-1354(00)00332-8
  19. Watts, R.J. and Dilly, S.E., 1996, Evaluation of iron catalysts for the Fenton-like remediation of diesel-contaminated soils, J. of Hazardous Materials, 51, 209-224 https://doi.org/10.1016/S0304-3894(96)01827-4
  20. Wu, R.C. and Papadopoulos, K.D., 2000, Electroosmotic flow through porous media: cylindrical and annular models, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 161, 469-476 https://doi.org/10.1016/S0927-7757(99)00209-5
  21. Yang, G.C.C. and Liu, C.Y., 2001, Remediation of TCE contaminated soils by in-situ EK-Fenton process, J. of Hazardous Materials, B85, 317-331
  22. Yang, G.C.C. and Long, Y.W., 1999, Removal and degradation of phenol in a saturated flow by in-situ electrokinetic remediation and Fenton-like process, J. of Hazardous Materials, B69, 259-271