화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Applied Chemistry for Engineering, Vol.30, No.4, 472-478, August, 2019
DOI10.14478/ace.2019.1042  Export Citation
축전식 탈염 시스템에서 전하량 제어를 통한 경도물질의 안정적인 탈염
Stable Desalination of Hardness Substances through Charge Control in a Capacitive Deionization System
김윤태, 최재환†
  • 공주대학교 화학공학부
Yoon-Tae Kim, and Jae-Hwan Choi†
  • Department of Chemical Engineering, Kongju National University, 1223-24, Cheonan-daero, Seobuk-gu, Cheonan, Chungnam 31080, South Korea
E-mail:
초록
막 축전식 탈염(MCDI) 셀에 공급하는 총 전하(TC)를 조절하여 경도물질(Ca2+)을 안정하게 탈염할 수 있는 방법을 연구하였다. 흡착과정에서 TC를 변화시키면서 흡착(1.5 V)과 탈착(0.0 V)을 30회 반복하였다. 탈염과정에서 유출수의 농도와 pH, 흡착 및 탈착량, 전류밀도와 셀 전위의 변화를 분석하였다. MCDI 셀에 사용된 탄소전극의 최대허용전하 (MAC)는 46 C/g로 측정되었다. MAC 이하의 TC (40 C/g)에서 운전한 결과 전극반응이 일어나지 않아 장기간 운전에서도 안정적인 탈염특성을 얻을 수 있었다. 반면, MAC 이상의 TC (50, 60 C/g)에서 운전한 경우 유출수의 농도와 pH가 크게 변하였다. 또한 전극반응으로 인해 전극표면에 스케일이 생성되어 셀의 전기저항이 점차 증가하였다. 이를 통해 흡착과정에서 MCDI 셀에 공급하는 전하를 제어함으로써 전극반응 없이 경도물질을 안정하게 제거할 수 있음을 확인 하였다.
A stable desalination method of the hardness substance such as Ca2+ by controlling the total charge (TC) supplied to the membrane capacitive deionization (MCDI) cell was studied. The adsorption (1.5 V) and desorption (0.0 V) were repeated 30 times while varying the TC in the adsorption process. The concentration and pH of effluent, adsorption and desorption amounts, current densities and cell potentials were analyzed in the desalination process. The maximum allowable charge (MAC) of the carbon electrode used in MCDI cell was measured to be 46 C/g. As a result of operation at TC (40 C/g) below the MAC value, electrode reactions did not occur, resulted in the stable desalination characteristics for a long-term operation. When operating at TCs (50, 60 C/g) above the MAC value, however, the concentration and pH of effluent varied greatly. Also, the scale was formed on the electrode surface due to electrode reactions, and the electric resistance of the cell gradually increased. It was thus concluded that it is possible to remove stably the hardness substance without any electrode reactions by controlling the charge supplied to MCDI cell during the adsorption process.
Keywords:Capacitive deionization;Maximum allowable charge;Electrode reactions;Electrode potential;Cell potential
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