아염소산나트륨(NaClO2)의 무격막 전기분해(un-divided electrolysis)에 의한 이산화염소(chlorine dioxide; ClO2) 제조에서 양전극(anode) 재질에 따른 이산화염소수 발생특성을 조사하였다. 양전극으로는 IrO2-coated Ti, RuO2-coated Ti, DSA(dimensionally stable anode) 전극을 사용하였으며, 음전극으로는 Pt-coated Ti 전극을 사용하였다. 다양한 양전극을 사용한 무격막 전해셀(un-divided electrochemical cell) 시스템에서 이산화염소의 전구체인 아염소산나트륨(NaClO2) 농도, 전해질로 사용된 염화나트륨(NaCl) 농도 그리고 전구체 용액의 전해셀 체류시간(cell residence time; tR), 전구체 용액의 초기 pH 그리고 무격막 전해셀에 공급된 전류(current; A)와 같은 운전 파라미터가 이산화염소수 발생에 미치는 영향을 조사하고 최적 운전조건을 도출하였다. IrO2-coated Ti, RuO2-coated Ti 그리고 DSA 양전극 시스템에서 최적 전해셀 체류시간은 각각 약 2.27, 1.52, 1.52 s, 전구체 용액의 초기 pH는 약 2.3, 최적 아염소산나트륨 농도는 IrO2-coated Ti와 RuO2-coated Ti 양전극 시스템이 약 0.43 g/L, DSA 양전극 시스템이 약 0.32 g/L 그리고 최적전해질 농도는 약 5.85 g/L로 나타났으며 무격막 전해셀에 공급된 최적 전류는 약 0.6 A로 나타났다. 산출된 최적 무격막 전해셀 조건에서 이산화염소수 발생을 위한 IrO2-coated Ti, RuO2-coated Ti 그리고 DSA 양전극 시스템의 전류효율(current efficiency; C.E.%)과 에너지 소모율(energy consumption; E.C. W·hr/g-ClO2)은 각각 약 79.80, 114.70, 70.99%_x000D_ 그리고 1.38, 1.03, 1.61 W·hr/g-ClO2로 나타났다.

A characteristic study of aqueous chlorine dioxide generation from sodium chlorite(NaClO2) by an undivided electrochemical cell with different anode materials were performed. IrO2-coated Ti, RuO2-coated Ti and DSA were used as anode materials and Pt-coated Ti electrode was used as cathode. Various electrochemical cell operating parameters such as cell residence time(tR), initial feed solution pH, sodium chlorite and sodium chloride(NaCl) concentration and applied current for the generation of chlorine dioxide in an un-divided cell were investigated and optimized. Estimated optimal cell residence times in IrO2-coated Ti, RuO2-coated Ti and DSA anode material systems were around 2.27, 1.52 and 1.52 sec, respectively. Observed optimum initial feed solution pH was around 2.3 in all anode material systems. Optimum sodium chlorite concentrations in IrO2-coated Ti, RuO2-coated Ti and DSA anode systems were around 0.43, 0.43 and 0.32 g/L, respectively. Optimum electrolyte concentration and applied current were around 5.85 g/L and 0.6 A in all anode systems. Current efficiencies of IrO2-coated Ti, RuO2-coated Ti and DSA anode systems under optimum conditions were 79.80, 114.70 and 70.99%, respectively. Obtained energy consumptions for the optimum generation of chlorine dioxide were 1.38, 1.03 and 1.61 W·hr/g-ClO2, respectively.

Chlorine Dioxide Un-Divided cell IrO2-Coated Ti RuO2-Coated Ti DSA

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