본 연구에서는 암모니아의 질소화 전해 특성을 알기 위하여 IrO₂ 전극을 사용하여 pH에 따른 암모니아의 전극 흡착 특성, 전해 반응 특성, 질소화 분해 반응 속도 및 반응 생성물의 변화, 염소, 이온의 암모니아 전해 반응에 대한 영향 등이 조사되었으며, 또한 암모니아의 분해 반응 기구가 제시되었다. 알칼리 영역에서 존재하는 암모니아는 전극의 흡착과정을 통하여 대부분 질소로 분해되며 이때 산소 발생은 거의 일어나지 않았다. 중성 및 산성에서 존재하는 암모늄 이온은 직접적인 전극 반응에 의한 분해가 아닌 산소 발생 영역에서 생성되는 OH 라디칼에 의한 간접 산화반응에 의해서 분해가 되었고 그 분해 속도는 알칼리 영역의 흡착에 의한 전극 분해 반응 속도보다 크게 낮았다. 전해 반응에 의해 발생되는 차아염소산 이온에 의한 암모니아와 암모늄 이온의 질소화 분해는 매우 효과적이었으며, 중성 영역에서는 질소로의 분해 외에 NOx로도 일부 분해 되었다.

In order to know the electrolytic decomposition characteristics of ammonia to nitrogen, this work has studied an adsorption and a electrolytic reaction of ammonia at an IrO₂ anode with a change of pH, and has evaluated the decomposition rate to nitrogen, the change of byproducts, and the effect of chloride ion on the decomposition reaction. Also, an electrolytic decomposition mechanism of ammonia was suggested. The ammonia in the basic solution was oxidized mainly to nitrogen gas through a direct electrolytic reaction accompanying adsorption at the electrode where the oxygen evolution hardly occurred. The ammonium ion in the neutral and acid solution could be partly decomposed to nitrogen by the OH radicals generated in the condition of oxygen evolution, not by the direct electrode reaction. However, the decomposition rate in the neutral or acid solution was much lower than that in the basic condition. The hypochlorite ion generated from chloride ion by the electrode was very effective for the decomposition of ammonia and ammonium ion to nitrogen. The ammonium ion by hypochlorite in neutral condition was partly changed to NOx gas as well as to nitrogen gas.

Electrolysis Ammonia Oxidation IrO₂ Catalytic Oxide Electrode DSA

Feng C, Sugiura N, Shimada S, Maekawa T, Journal of Hazardous Materials, B103, 65 (1992)
Bae SK, Park SC, J. of Kor. Soc. Env. Engs., 6(1), 44 (1984)
Lin SH, Wu CL, Water Res., 30(3), 715 (1996) 
Bouwer EJ, Crowe PB, J AWWA, 80(9), 82 (1988)
Grimm J, Bessarabov D, Sanderson R, Desalination, 115(3), 285 (1998) 
Trasatti S, Electrochim. Acta, 36(2), 225 (1991) 
Trasatti S, Electrode of Conductive Metallic Oxides, Part A, Elsevier Sci. Pub. Co., Amsterdam (1980)
Kim KW, Lee EH, Kim JS, Shin KH, Kim KH, Electrochim. Acta, 46(6), 915 (2001) 
Kim KW, Lee EH, Kim JS, Shin KH, Jung BI, Electrochim. Acta, 47(15), 2525 (2002) 
Kim KW, Lee EH, Kim JS, Shin KH, Jung BI, J. Electrochem. Soc., 149(12), D187 (2002) 
Echigo S, Yamada H, Matsui S, Kawanishi S, Shishida K, Water Sci. Technol., 34, 81 (1996)
Floyd RA, Soong LM, Biochem. Biophys. Res. Commun., 74(1), 79 (1977) 
Vooys ACA, Santen RA, Veen JAR, J. Mol. Catal. A-Chem., 154, 203 (2000) 
Pintar A, Batista J, Levec J, Kajiuchi T, Appl. Catal. B: Environ., 11(1), 81 (1996) 
Bryabt EA, Fulton GP, Budd GC, Disinfection Alternatives for Safe Drinking Water, Van Nostrand Reinhold, N.Y (1992)
Plieth WJ, Bard AJ, Encyclopedia of Electrochemistry of the Elements, Marcel Dekker, Vol VIII, Ch.5(1978)
Bockris JO, Kim J, J. Appl. Electrochem., 27(6), 623 (1997) 
Sasaki K, Hisatomi Y, J. Eectrochem. Soc., 117(6), 758 (1970)
Comninellis C, Electrochim. Acta, 39(11-12), 1857 (1994) 
Kim KW, Lee EH, Kim YJ, Lee MH, Kim KH, Shin DW, J. Photochem. Photobiol. A-Chem., 159, 301 (2003)