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유전체장벽방전 플라즈마 반응기를 이용한 항생제의 분해특성에 관한 연구

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Abstract
The objective of this work is to investigate the degration characteristics of antibiotics, such as sulfonamides (sulfathiazole (STZ), sulfamethazine (SMT)
and sulfamethoxazole (SMZ)) and fluoroquinolones (ciprofloxacin (CIP) and enro floxacin (ENR)) using dielectric barrier discharge(DBD) plasma reactor. For this purpose, the effects of operating conditions, such as working gas type (dry air and pure oxygen), gas flow rate, applied voltage and initial antibiotic
concentration on their degradation are examined. Moreover, their possible degradation pathways are proposed by identification of the intermediates formed
during their degradation by means of LC?TOF-MS. The results obtained are summarized as follows. Ozone concentration and its generation rate increase with increasing applied voltage. With increasing gas flow rate, ozone concentration decreases, regardless of gas type, and its generation rate increases when a pure oxygen as a working gas is used, and increases below a fixed gas flow rate and decreases above the flow rate due to the scavenging effect of ozone by nitrogenous compounds formed, when a dry air is used. When a dry air as a working gas is used, the degradation rate of STZ increases in the range of flow rate of 0.1 ~ 0.5 L/min but above the flow rate, decreases because of the decrease of active species formed and a short contact time between active species and STZ. With increasing applied voltage, its degradation rate increases sharply in a early stage and slowly after the stage. The degradation rate of antibiotics is higher for a pure oxygen than for a dry air as a working gas, is generally higher for sulfonamides than fluoroquinolones, decreases in the order of SMT > STZ > ENR, SMZ > CIP among the antibiotics, and decreases with increasing initial antibiotic concentration. With increasing the treatment time of DBD plasma, the absorbance at λmax of each antibiotics gradually decreases, indicating that its original compound is degraded into mineralization; the pH of the solution changes more greatly for a pure oxygen than a dry gas, as a working gas, and for fluoroquinolones than for sulfonamides among the antibiotics; the conductivity increases nearly linearly for a dry gas and for a pure oxygen, it increases rapidly in an early stage and slowly after the stage, and increases more rapidly for sulfonamides than for fluoroquinolones; the removal efficiency of TOC is higher for a pure oxygen than for a dry air and for fluoroquinolones than sulfonamides. From the mineralization of antibiotics by plasma treatment, ions (SO42-, NO3-and NH4+) and organic acids (acetate, formate and oxalate) for sulfonamides, and ions (F-, NO3- and NH4+) and organic acids (acetate, formate and oxalate)for fluoroquilnolones, are formed. The above ions and organic acids increase with increasing the treatment time, and increase more rapidly and their concentrations are higher for a pure gas than for a dry air, as a working gas. After 60 min treatment time of DBD plasma using a pure oxygen as a working gas, the transformed ratio of sulfonamides into SO42- is in the range of 66.9 ~ 86.4%, and decreases in the order of STZ > SMZ > SMT among the sulfonamides, and the transformed ratio of fluoroquilnolones into F- is in the range of 91.0 ~ 97.4%, and decreases in the order of ENR > CIP among the fluoroquilnolones. And the transformed ratio of antibiotics into NH4+ plus NO3- is in the range of 15.7 ~ 33.2%, showing a lower transformed ratio, compared
with that into SO42- or F-, and is higher for sulfonamides than for fluoroquilnolones. It can be found that the nitrogen contained in sulfonamides trandforms into NH4+ than NO3- but he nitrogen contained in fluoroquilnolones trandforms into NO3- than NH4+. The concentration of organic acids formed from the degradation of antibiotics decreases in the order of formate > oxalate > acetate for STZ, ENR and CIP
and in the order of formate > acetate > oxalate for SMT and SMZ, indicating that the concentration of organic acids formed varies depending on the antibiotics. And it can be found that with the treatment time up to 60 min of DBD plasma, the concentration of acetate and formate reaches to a maximum and then decreases slowly, and the concentration of oxalate increases continuously. The possible degradation pathways of antibiotics are proposed by identification of the intermediates formed during their degradation by means of LC?TOF-MS. From these results, it is considered most intermediates may be
the products formed by the reaction of hydroxylation or oxidation.
Author(s)
김길성
Issued Date
2013
Awarded Date
2013. 8
Type
Dissertation
URI
http://dcoll.jejunu.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000006502
Alternative Author(s)
Kim, Kil Seong
Affiliation
제주대학교 대학원
Department
대학원 환경공학과
Advisor
Sang-Kyu Kam
Table Of Contents
I. 서 론 1
II. 이론적 고찰 4
1. 플라즈마 4
1) 플라즈마의 정의 및 종류 4
2) 플라즈마 생성 및 방전에 의한 활성종 생성기구 7
3) 활성종의 특성 9
4) 플라즈마 장치를 이용한 수처리기술 15
2. 항생제 16
1) 항생제의 종류 16
2) 항생제 사용량 20
3) 환경 중 노출실태 25
4) 항생제의 처리기술 29
III. 실험장치 및 방법 30
1. DBD 플라즈마 반응기 30
2. 실험재료 32
3. 분석방법 34
1) 항생제 및 분해산물의 분석 34
2) 음?양이온 및 유기산의 분석 37
3) 오존, 전기전도도, 수소이온농도, 총유기탄소 등의 분석 37
4. 분해특성에 대한 실험 방법 39
1) DBD 플라즈마 반응기 특성 39
2) 처리효율 39
3) 분해특성 40
4) 분해경로 40
IV. 결과 및 고찰 42
1. DBD 플라즈마 반응기 특성 42
1) 방전전력 42
2) 오존생성 특성 46
2. DBD 반응기의 운전조건에 따른 처리 효율 50
1) 가스의 유량변화에 따른 처리효율 50
2) 인가전압의 변화에 따른 처리효율 56
3) 유입가스의 종류에 따른 처리효율 64
4) 초기농도 변화에 따른 처리효율 71
3. 항생제의 분해특성 78
1) 분광학적 특성 78
2) pH의 변화 81
3) 전기전도도의 변화 85
4) TOC 변화 87
5) 분해산물의 생성 90
4. 항생제 분해경로 111
1) Sulfonamide계 111
2) Fluoroquinolone계 129
V. 결 론 142
VI. 참고문헌 145
Degree
Doctor
Publisher
제주대학교 대학원
Citation
김길성. (2013). 유전체장벽방전 플라즈마 반응기를 이용한 항생제의 분해특성에 관한 연구
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