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


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.


Supported by : 한국환경산업기술원


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