HWAHAK KONGHAK, Vol.32, No.3, 385-392, June, 1994
질소를 함유한 방향족 유기화합물의 초임계수산화
Supercritical Water Oxidation of Nitrogen Containing Aromatic Compounds
초록
질소를 함유한 대표적인 유기오염물로서 aniline, pyridine, nitrobenzene을 선정하여 초임계수산화에 의한 분해율과 분해 후의 부산물의 확인(identification) 및 질소의 거동에 대해 조사하고자 하였으며 비교를 위하여 benzene, toluene, phenol 등에 대한 조사도 병행하였다. 본 연구에서 조사된 질소함유 방향족 화합물은 질소를 함유하지 않은 방향족 화합물보다 초임계수에서의 산화반응이 느리게 진행되며 분해속도를 느린 것부터 빠른 것의 차례로 나열하면 pyridine<aniline <nitrobenzene<phenol<benzene, toluene으로 된다. 이들은 실험조건에서 방향족 고리구조를 가지는 여러 종류의 안덩한 최종부산물을 형성시킨다. 분해된 화합물의 질소는 pyridine의 경우 80-100%가, aniline의 경우 약 50-70%가 암모니아로 전환된 반면, nitrobenzene의 경우에는 암모니아의 발생은 10%미만에 그쳤다. 어떤 경우이든 NO2-나 NO3-의 형성은 매우 미미하였으며 질소의 나머지 부분은 최종유기부산물에 포함된 것을 제외하면 N2로 전환된 것으로 판단된다. 이들 화합물들을 초임계수산화에 의해 완벽하게 처리하기 위해서는 반응온도를 500℃보다 훨씬 높이거나 촉매가 사용되어야 할 필요가 있을 것으로 보인다.
The performance of supercritical water oxidation(SCWO) was investigated for the destruction of pyridine, aniline, nitrobenzene. Three aromatic compounds including benzene, toluene, and phenol were also tested under similar conditions for the comparison of destruction performance of SCWO. Pyridine was the most difficult to destroy, nitrobenzene being the easiest among the three compounds with nitrogen. The destruction rates of the three aromatic compounds with nitrogen were slower than the other three without nitrogen. All the major organic by-products from the three nitrogen containing compounds were identified as having the aromatic ring structures. Virtually all(80-100%) of nitrogen from the destruction of pyridine was converted to ammonia. Less portion(50-70%)of nitrogen was converted to ammonia in SCWO of aniline. The ammonia yield was less than 10% of nitrogen from the destruction of nitrobenzene. Neither nitrite ion nor nitrate ion were formed in appreciable quantities. Significant portion of nitrogen from the SCWO of aniline and nitrobezene is expected to be converted to nitrogen gas(N2). It appears that reaction temperatures substantially higher than 500℃ and/or catalysts are required for the faster and complete destruction of these nitrogen containing aromatic compounds by SCWO.
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