Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Comparison of Selective Removal of Nitrate Ion in Constant Voltage and Constant Current Operation in Capacitive Deionization

축전식 탈염에서 정전압과 정전류 운전에 따른 질산 이온의 선택적 제거율 비교

  • Choi, Jae-Hwan (Department of Chemical Engineering, Kongju National University) ;
  • Kim, Hyun-Ki (Department of Chemical Engineering, Kongju National University)
  • Received : 2014.07.21
  • Accepted : 2014.09.04
  • Published : 2015.06.01
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Abstract

The adsorption characteristics of ions were evaluated for the nitrate-selective carbon electrode (NSCE) in accordance with power supply methods. The NSCE was fabricated by coating the surface of a carbon electrode with anion-exchange resin powders with high selectivity for the nitrate ion. Capacitive deionization (CDI) experiments were performed on a mixed solution of nitrate and chloride ion in constant voltage (CV) and constant current (CC) modes. The number of total adsorbed ions in CV mode was 15% greater than that in CC mode. The mole fraction of adsorbed nitrate ion showed the maximum 58%, though the mole fraction was 26% in the mixed solution. This indicates that the fabricated NSCE is highly effective for the selective adsorption of nitrate ions. The mole fraction of adsorbed nitrate was nearly constant value of 55-58% during the adsorption period in CC mode. In the case of CV mode, however, the values increased from the initial 30% to 58% at the end of adsorption. We confirmed that the current supplied to cell is important factor to determine the selective removal of nitrate.

질산이온 선택성 탄소전극(NSCE, nitrate-selective carbon electrode)에서 전원공급 방식에 따른 이온들의 흡착특성을 분석하였다. 질산이온에 선택성이 높은 음이온수지 분말을 탄소전극에 코팅하여 NSCE를 제조하였다. 질산과 염소이온의 혼합용액에 대해 정전압(CV, constant voltage)과 정전류(CC, constant current) 모드에서 축전식 탈염(CDI, capacitive deionization)을 실시하였다. 이온들의 총 흡착량은 CV 모드로 운전한 경우 CC 모드에 비해 약 15% 증가하였다. 혼합용액에서 질산이온의 비율은 26%로 낮았지만 흡착된 질산이온의 몰비율은 최대 58%로 나타나 NSCE가 질산이온을 선택적으로 제거하는데 효과적임을 확인하였다. CC 모드에서 운전한 경우 흡착된 질산이온의 몰비율은 흡착기간 동안 55~58%로 일정하였다. 반면 CV 모드에서는 30~58%로 큰 차이를 보였다. 이를 통해 셀에 공급되는 전류가 질산이온의 선택적 제거율을 결정하는데 중요한 인자임을 알 수 있었다.

Keywords

References

  1. Porada, S., Zhao, R., van der Wal, A., Presser, V. and Biesheuvel, P. M., "Review on the Science and Technology of Desalination by Capacitive Deionization," Prog. Mater. Sci., 58, 1388-1442(2013). https://doi.org/10.1016/j.pmatsci.2013.03.005
  2. Oren, Y., "Capacitive Deionization (CDI) for Desalination and Water Treatment-Past, Present and Future (a Review)," Desalination, 228, 10-29(2008). https://doi.org/10.1016/j.desal.2007.08.005
  3. Son, W. K., Kim, T. I., Han, H. J. and Kang, K. S., "The Study of Capacitive Deionization Technology by the Analysis of Patents and Papers," Korean Chem. Eng. Res., 49, 697-703(2011). https://doi.org/10.9713/kcer.2011.49.6.697
  4. Anderson, M. A., Cudero, A. L. and Palma, J., "Capacitive Deionization as an Electrochemical Means of Saving Energy and Delivering Clean Water. Comparison to Present Desalination Practices: Will it Compete?," Electrochim. Acta, 55, 3845-3856(2010). https://doi.org/10.1016/j.electacta.2010.02.012
  5. Zhao, R., Biesheuvel, P. M., Miedema, H., Bruning, H. and van der Wal, A., "Charge Efficiency: a Functional Tool to Prove the Double-layer Structure Inside of Porous Electrodes and Application in the Modeling of Capacitive Deionization," J. Phys. Chem. Lett., 1, 205-210(2010). https://doi.org/10.1021/jz900154h
  6. Welgemoed, T. J. and Schutte, C. F., "Capacitive Deionization TechnologyTM : An Alternative Desalination Solution," Desalination, 183, 327-340(2005). https://doi.org/10.1016/j.desal.2005.02.054
  7. Park, B. H. and Choi, J. H., "Improvement in the Capacitance of a Carbon Electrode Prepared Using Water-soluble Polymer Binder for a Capacitive Deionization Application," Electrochim. Acta, 55, 2888-2893(2010). https://doi.org/10.1016/j.electacta.2009.12.084
  8. Lee, J. H., Bae, W. S. and Choi, J. H., "Electrode Reactions and Adsorption/Desorption Performance Related to the Applied Potential in a Capacitive Deionization Process," Desalination, 258, 159-163(2010). https://doi.org/10.1016/j.desal.2010.03.020
  9. Ryoo, M. W. and Seo, G., "Improvement in Capacitive Deionization Function of Activated Carbon Cloth by Titania Modification," Water. Res., 37, 1527-1534(2003). https://doi.org/10.1016/S0043-1354(02)00531-6
  10. Zou, L., Morris, G. and Qi, D., "Using Activated Carbon Electrode in Electrosorptive Deionization of Brackish Water," Desalination, 225, 329-340(2008). https://doi.org/10.1016/j.desal.2007.07.014
  11. Xu, P., Drewes, J. E., Heil, D. and Wang, G., "Treatment of Brackish Produced Water Using Carbon Aerogel-based Capacitive Deionization Technology," Water. Res., 42, 2605-2617(2008). https://doi.org/10.1016/j.watres.2008.01.011
  12. Pan, L., Wang, X., Gao, Y., Zhang, Y., Chen, Y. and Sun, Z., "Electrosorption of Anions with Carbon Nanotube and Nanofibre Composite Film Electrodes," Desalination, 244, 139-143(2009). https://doi.org/10.1016/j.desal.2008.05.019
  13. Li, H., Zou, L., Pan, L. and Sun, Z., "Novel Graphene-like Electrodes for Capacitive Deionization," Environ. Sci. Technol., 44, 8692-8697(2010). https://doi.org/10.1021/es101888j
  14. Li, H., Pan, L., Lu, Y., Zhan, Y., Nie, C. and Sun, Z., "A Comparative Study on Electrosorptive Behavior of Carbon Nanotubes and Graphene for Capacitive Deionization," J. Electroanal. Chem., 653, 40-44(2011). https://doi.org/10.1016/j.jelechem.2011.01.012
  15. Andelman, M. D., "Charge Barrier Flow-through Capacitor," CA Patent NO. 2,444,390(2002).
  16. Kim, Y. J. and Choi, J. H., "Improvement of Desalination Efficiency in Capacitive Deionization Using a Carbon Electrode Coated with an Ion-exchange Polymer," Water. Res., 44 (2010) 990-996. https://doi.org/10.1016/j.watres.2009.10.017
  17. Kim, Y. J. and Choi, J. H., "Selective Removal of Nitrate Ion Using a Novel Composite Carbon Electrode in Capacitive Deionization," Water Res., 46, 6033-6039(2012). https://doi.org/10.1016/j.watres.2012.08.031
  18. Yeo, J. H. and Choi, J. H., "Enhancement of Nitrate Removal from a Solution of Mixed Nitrate, Chloride and Sulfate Ions Using a Nitrate-selective Carbon Electrode," Desalination, 320, 10-16(2013). https://doi.org/10.1016/j.desal.2013.04.013
  19. Zhao, R., Biesheuvel, P. M. and van der Wal, A., "Energy Consumption and Constant Current Operation in Membrane Capacitive Deionization," Energy Environ. Sci., 5, 9520-9527(2012). https://doi.org/10.1039/c2ee21737f
  20. Jande, Y. A. C. and Kim, W. S., "Desalination Using Capacitive Deionization at Constant Current," Desalination, 329, 29-34(2013). https://doi.org/10.1016/j.desal.2013.08.023
  21. Zhao, R., Satpradit, O., Rijnaarts, H. H. M., Biesheuvel, P. M. and van der Wal, A., "Optimization of Salt Adsorption Rate in Membrane Capacitive Deionization," Water Res., 47, 1941-1952(2013). https://doi.org/10.1016/j.watres.2013.01.025
  22. Helfferrich, F., Ion Exchange, Dover Publications, New York, NY(1962).
  23. Zhao, R., Porada, S., Biesheuvel, P. M., van der Wal, A., "Energy Consumption in Membrane Capacitive Deionization for Different Water Recoveries and Flow Rates, and Comparison with Reverse Osmosis," Desalination, 330, 35-41(2013). https://doi.org/10.1016/j.desal.2013.08.017
  24. Choi, J. H., "Determination of the Electrode Potential Causing Faradaic Reactions in Membrane Capacitive Deionization," Desalination, 347, 224-229(2014). https://doi.org/10.1016/j.desal.2014.06.004
  25. Strathmann, H., Ion-Exchange Membrane Separation Processes, Elsevier B. V., Amsterdam(2004).