Effects of Immobilized Bipolar Interface Formed by Multivalent and Large Molecular Ions on Electrodialytic Water Splitting at Cation-Exchange Membrane Surface

양이온교환막 표면의 전기투석 물분해에서 다가의 큰 이온성분자에 의해 형성된 고정층 바이폴라 계면의 영향

  • Seung-Hyeon Moon (Department of Environmental Science and Engineering, Kwangju Institute of Science & Technology (K-JIST)) ;
  • Moon-Sung Kang (Department of Environmental Science and Engineering, Kwangju Institute of Science & Technology (K-JIST)) ;
  • Yong-Jin Choi (Department of Environmental Science and Engineering, Kwangju Institute of Science & Technology (K-JIST))
  • Published : 2003.09.01

Abstract

The effects of bipolar interface formed on the surface of cation-exchange membrane on water splitting phenomena were investigated. Results showed that the formation of immobilized bipolar interface resulted in significant water splitting during electrodialysis. In particular, the immobilized bipolar interface was easily created on the cation-exchange membrane surface in the electrodialytic systems where multivalent cations served as an electrolyte. Multivalent cations with low solubility product resulted in violent water splitting because they were easily precipitated on the membrane surface in hydroxide form. Therefore, the bipolar interface consisting of H- and OH-affinity groups were formed on the membrane-solution interface. Apparently, water splitting was largely activated with the help of strong electric fields generated between the metal hydroxide layer and fixed charge groups on the membrane surface. Likewise, the accumulation of large molecular counter ions on the membrane surface led to the formation of a fixed bipolar structure that could cause significant water splitting in the over-limiting current region. Therefore, the prevention of the immobilization of bipolar interface on the membrane surface is very essential in improving the process efficiency in a high-current operation.

본 연구에서는 양이온교환막 표면에 형성된 바이폴라 계면이 물분해 현상에 미치는 영향을 조사하였다. 실험결과, 전기투석 중 막표면에 형성된 고정화된 바이폴라 계면이 심각한 물분해를 유발함을 알 수 있었다. 특히, 고정화된 바이폴라 계면은 다가 양이온이 전해질로 이용되는 전기투석 시스템에서 양이온교환막 표면에 쉽게 형성됨을 알 수 있었다. 낮은 용해도적 상수를 갖는 다가 양이온들은 급격한 물분해를 유발하였는데 이는 이들이 막표면에서 쉽게 수산화물의 형태로 침적되며 따라서 수소-친화 그룹과 수산화-친화 그룹으로 구성된 바이폴라 계면이 막-용액 계면에 형성됨을 알 수 있었다. 따라서 물분해는 막 표면의 금속수산화물 층과 막의 고정전하 그룹간에 발생되는 강한 전기장에 의해 크게 활성화됨을 알수 있다. 또한 이와 유사하게 분자량이 큰 유기 상대이온들이 막표면에 누적되는 경우에도 고정화된 바이폴라 계면이 형성되어 한계전류밀도 이상에서 심각한 물분해를 유발하였다. 따라서 전기투석의 고전류 운전시 효율 향상을 위해서는 막표면에 유발되는 고정화된 바이폴라 계면의 형성을 억제하는 것이 매우 중요함을 알 수 있다.

Keywords

References

  1. FIL-IDF Bulletin v.212 Electrodialysis applications in whey processing Batchelder,B.T.
  2. Desalination v.32 Electrodialytic recovery process of metal-finishing waste-water Itoi,S.;I.Nakamura;T.Kawahara https://doi.org/10.1016/S0011-9164(00)86038-5
  3. J. Appl. Electrochem. v.27 Lactic acid production by electrodialysis Part 1: Experimental tests Boniardi,N.;R.Rota;G.Nano;B.Mazza https://doi.org/10.1023/A:1018439604632
  4. J. Membr. Sci. v.108 Behavior of citric acid during electrodialysis Novalic,S.;F.Jagschits;J.Okwor;K.D.Kulbe https://doi.org/10.1016/0376-7388(95)00159-X
  5. J. Membr. Sci. v.145 Lactic acid recovery using two-stage electrodialysis and its modeling Lee,E.G.;Moon,S.H.;Chang,Y.K.;Yoo,I.K.;Chang,H.N. https://doi.org/10.1016/S0376-7388(98)00065-9
  6. J. Chem. Technol.and Biotechnol. v.176 Lactic Acid Recovery from Fermentation Broth Using One-stage Electrodialysis Kim,Y.H.;Moon;S.H.
  7. Ph.D thesis, K-JIST Transport phenomena in ion-exchange membranes at under- and over-limiting current regions Choi,J.H.
  8. Trans IChemE v.60 Electrodialysis at high current density using a laboratory stack Makai,A.J.;J.C.R.Turner
  9. Russian J. Electrochem v.30 no.12 Water dissociation rate at cartion-exchange membrane: Influence of insoluble metal hydroxides Shel'desov,N.V.;Zabolotskii,V.I.;Ganych,V.V.
  10. Ph.D thesis, K-JIST Water-Splitting Phenomena and Applications in Ion-Exchange Membranes Kang,M.S.
  11. J. Member. Sci. v.207 no.2 Water-swollen cation-exchange membranes prepared using PVA(polyvinyl alcohol)/PSSA-MA(plolystyrene sulfonic acid-co-maleic acid) Kang,M.S.;Choi,Y.J.;Moon,S.H. https://doi.org/10.1016/S0376-7388(02)00172-2
  12. J. Colloid & Interf. Sci. v.241 Heterogeneity of ion-exchange membranes: The effects of membrane heterogeneity on transport properties Choi,J.H.;Kim,S.H.;Moon,S.H. https://doi.org/10.1006/jcis.2001.7710
  13. Water chemistry Snoeyink,V.L.;Jenkins,D.
  14. J. Membr. Sci. v.147 Membrane catalytic deprotonation effects Jialin,L.;Yazhen,W.;Changying,Y.;Guangdou,L;Hong,S. https://doi.org/10.1016/S0376-7388(98)00126-4
  15. Electrochim. Acta v.30 no.3 Water splitting in ion exchange membranes Simons,R. https://doi.org/10.1016/0013-4686(85)80184-5
  16. J. Membr. Sci. v.78 Preparation of a high performance bipolar membrane Simons,R. https://doi.org/10.1016/0376-7388(93)85243-P
  17. US Patent 5,221,455 Bipolar membrane and method for its production Hanada,F.;Hirayama,K.;Ohmura,N;Tanaka,S.
  18. Korean J. Chem. Eng. v.19 no.1 Effects of Interface Hydrophilicity and Metallic Compounds on Water-Splitting Efficiency in Bipolar Membranes Kang,M.S.;Tanioka,A.;Moon,S.H. https://doi.org/10.1007/BF02706881
  19. Principles and Applications of Electro-chemistry(4$^{th}$ Ed.) Crow,D.R.
  20. J. Electrochem. Soc. v.145 no.6 Current distribution on a rotating disk electrode below the mass-transfer-limited current Durbha,M.;Orazem,M.E. https://doi.org/10.1149/1.1838579
  21. J. Electrochem. Soc. v.142 no.6 Coulometry of a mass-transfer limited reaction with a membrane-covered rotating disk electrode Fedkiw,P.S.;Song,S.;Sharma,S.;Ye,J.H. https://doi.org/10.1149/1.2044213
  22. Fundamentals of Electrochemistry Bagotzky,V.S.
  23. J. Power Sources v.83 Impedance characteristics of a rotating disk electrode coated with a sulfonated polysulfone cation-exchange membrane Park,S.Y.;Lee,J.W.;Jang,S.H.;Kim,L.H.;Choi,D.K.;Joe,Y.I. https://doi.org/10.1016/S0378-7753(99)00305-5
  24. Electrochim. Acta v.44 Influence of surface phenomena on the impedance response of a rotating disk electrode Orazem,M.E.;Durbha,M.;Deslouis,C.;Takenouti,H.;Tribollet,B. https://doi.org/10.1016/S0013-4686(99)00156-5
  25. Surface Chemistry and Electrochemistry of Membranes Srensen,T.S.(ed.)
  26. The Physical Chemistry of Membranes Starzak,M.E.
  27. J. Membr. Sci. v.191 Pore size characterization of cation-exchange membranes by chrono-potentiometry using homologous amine ions Choi,J.H.;Moon,S.H. https://doi.org/10.1016/S0376-7388(01)00513-0