이산화납 전극 제조 시 전기화학적 증착인자가 수산화라디칼 발생에 미치는 영향 = Effects of Electrodeposition Parameters on Electrochemical Hydroxyl Radical Evolution of PbO₂ Electrode

국문 초록 (Abstract)

Lead dioxide (PbO₂)는 전기화학적 고도산화공정(electrochemical advanced oxidation process, EAOP)에서 hydroxyl radical (˙OH) 발생에 기반한 유기오염물 분해에 효과적인 전극물질이다. PbO₂ 전극의 대표적인 제조방법인 전기화학적 증착법(electrodeposition)의 주요 인자로는 전류/전압세기, 온도, 반응시간, Pb(II)의 농도, 전해질 종류 및 농도가 있다. 본 연구에서는 Ti/PbO₂ 산화전극을 전기화학적 증착법을 통해 전류인가 시간, 전류밀도, 온도, HNO₃3 전해질 농도를 각각 조절하여 제조하였고, ˙OH 검출물질인 p-Nitrosodimethylaniline (RNO)의 전기화학적 탈색 측면에서 ˙OH 발생에 대한 PbO₂ 증착인자의 영향을 조사하였다. 주요 결과로, PbO₂의 ˙OH 발생 성능은 PbO₂ 증착과정에서 대체로 전류인가 시간이 길어질수록(1-90 min), 전류밀도가 감소할수록(0.5-50 ㎃/㎠), 증착온도가 증가할수록(5-65℃), HNO3 전해질 농도(0.01-1.0 M)가 감소할수록 향상되었다. 특히, 0.01 M의 낮은 HNO₃3 농도 상에서 20 ㎃/㎠ 전류를 10분 이상 인가하여 증착시킨 PbO₂에서 ˙OH 발생이 가장 촉진되었다. RNO 탈색속도 측면에서 가장 성능이 좋은 PbO₂와 저조한 PbO₂ 사이에 최대 41% 정도 차이가 나타났다. PbO의 ˙OH 발생 성능을 결정짓는 특성으로 PbO₂ 층 전도도, Ti 기판 산화, PbO₂ 결정크기를 고려한 결과, PbO₂ 층의 전도도 및 Ti 기판의 산화가 ˙OH 발생에 주요하게 영향을 미치는 것으로 확인되었다. PbO₂ 층의 전도도 향상과 Ti 표면 산화 억제로 인한 Ti/PbO₂ 계면에서 전도도 향상이 ˙OH 발생을 촉진시키는 효과를 가져왔다. 그리고 일부 전극에서는 표면에서 PbO₂ 결정 크기 증가가 ˙OH 발생을 저감시키는 역할을 하였다.

다국어 초록 (Multilingual Abstract)

Lead dioxide (PbO₂) is an electrode material that is effective for organic pollutant degradation based on hydroxyl radical (˙OH) attack. Representative parameters for PbO₂ electrodeposition are summarized to current, temperature, reaction time, concentration of Pb(II) and electrolyte agent. In this study, Ti/PbO₂ electrodes were fabricated by electrodeposition method under controlled reaction time, current density, temperature, concentration of HNO₃ electrolyte. Effects of deposition parameters on ˙OH evolution were investigated in terms of electrochemical bleaching of p-Nitrosodimethylaniline (RNO). As major results, the ˙OH evolution was promoted at the PbO₂ that was deposited in longer reaction time (1-90 min), lower current density (0.5-50 ㎃/㎠), higher temperature (5-65℃) and lower HNO₃ concentration (0.01-1.0 M). Especially, the PbO₂ which was deposited in 0.01 M of lowest HNO₃ concentration by applying 20 ㎃/㎠ for above 10 min was most effective on ˙OH evolution. The performance gap between PbO₂s that was best and worst in ˙OH evolution was about 41%. Among the properties of PbO₂ related on ˙OH evolution performance, conductivity of Ti/PbO₂ significantly influenced on ˙OH evolution. The increase in conductivity promoted ˙OH evolution. In addition, the increase in crystal size of PbO₂ interfered ˙OH evolution at surface of some PbO₂ deposits.

목차 (Table of Contents)

• Abstract
• 요약
• 1. 서론
• 2. 실험방법
• 3. 결과 및 고찰
• 4. 결론
• References

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