• 산업기술연구
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• 제22권B호
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• pp.117-124
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• 2002

We prepared the nano-sized $TiO_2$ particles by the diffusion flame reactor and investigated the effects of several process variables on the generation and transport properties of $TiO_2$ particle. As the length from the tip of diffusion flame reactor increases, the size of $TiO_2$ particle increases by the coagulation between particles. The structure of $TiO_2$ particles prepared is almost found to be anatase. It was found that the $TiO_2$ particle size depends more largely on the change of reactor temperature than on the change of inlet $TiCl_4$ concentration. By the photo-degradation experiment of phenol and toluene with the prepared $TiO_2$ particles, we found that the photo-degradation efficiencies of phenol and toluene change, depending on the process variables such as size of $TiO_2$ photocatlysts, concentration of phenol or toluene. Degradation efficiencies of phenol and toluene was above 90% in our experiments in 60 minutes.

• 한국물환경학회지
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• 제24권1호
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• pp.118-122
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• 2008

Degradations of phenol and chlorinated compounds mixtures were studied with ultrasound of 20 kHz and 0.57, 1.14 W/mL. In presence of carbon tetrachloride (CT), degradation rate of phenol is faster than chloroform (CF), dichloromethane (DCM) and phenol solution. It is due to that CT generates of free chlorine (HOCl and $OCl^-$) from the sonochemical degradation and plays a role of hydrogen atom scavenger. CF and DCM are react with free chlorine, so amount of free chlorine is smaller than CT solution. The degradation rates of chlorinated compounds decreased with co-presence of phenol in the solution due to the distribution ultrasonic energy to both compounds. The measured chloride ion was lower than the theoretical concentration assuming complete degradation. This means not all the contaminants destructed went through complete degradation.

• 한국환경과학회지
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• 제25권7호
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• pp.905-916
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• 2016

The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.

• 한국환경과학회지
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• 제22권7호
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• pp.915-923
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• 2013

Decomposition of non-biodegradable contaminants such as phenol contained in water was investigated using a dielectric barrier discharge (DBD) plasma reactor in the aqueous solutions with continuous oxygen bubbling. Effects of various parameters on the removal of phenol in aqueous solution with high-voltage streamer discharge plasma are studied. In order to choose plasma gas, gas of three types (argon, air, oxygen) were investigated. After the selection of gas, effects of 1st voltage (80 ~ 220 V), oxygen flow rate (2 ~ 7 L/min), pH (3 ~ 11), and initial phenol concentration (12.5 ~ 100.0 mg/L) on phenol degradation and change of $UV_{254}$ absorbance were investigated. Absorbance of $UV_{254}$ can be used as an indirect indicator of phenol degradation and the generation and disappearance of the non-biodegradable organic compounds. Removal of phenol and COD were found to follow pseudo first-order kinetics. The removal rate constants for phenol and COD of phenol were $5.204{\times}10^{-1}min^{-1}$ and $3.26{\times}10^{-2}min^{-1}$, respectively.

• 산업기술연구
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• 제21권A호
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• pp.273-278
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• 2001

In this study, we prepared nano-sized $TiO_2$ particles for various process variables by the diffusion flame reactor and we collected $TiO_2$ particles by thermophoresis. It is found that the size of $TiO_2$ particles increases, as the flame temperature or the inlet $TiCl_4$ concentration increase or the total gas flow rate decreases. We investigated the photo-degradation of phenol wish the prepared $TiO_2$ particles. We found the optimum amounts of $TiO_2$ photocatalysts for our experimental apparatus and investigated the photo-degradation efficiencies of phenol, changing the process variables such as size of $TiO_2$ photocatlysts, phase ratio of rutile/anatase, concentration of phenol, input ratio of $O_2$. Degradation efficiencies of phenol were almost 95% in 15 minutes for the standard conditions of our experiments.

• 대한환경공학회지
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• 제32권3호
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• pp.241-247
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• 2010

오존 접촉 반응기에서 용존 오존 농도 및 페놀 제거에 미치는 운전변수의 영향에 대해 실험실 규모 실험을 수행하였다. 반응기로 가스상 오존이 공급되고 일정한 시간이 경과한 후에 용존 오존 농도는 포화 농도에 도달하였으며 포화 농도의 크기는 운전 변수에 의해 영향을 받는 것으로 나타났다. 수용액내의 오존은 높은 pH 조건에서 불안정하므로 용존 오존 농도는 용액의 초기 pH값이 증가함에 따라 감소하였다. 일정한 유량의 기체가 반응기로 공급되는 조건에서 가스상 오존 농도의 크기는 용존 오존의 포화농도에 중요한 영향을 미치며 일정한 농도의 가스상 오존이 공급될 때 가스 유량은 용존 오존이 포화되는 속도에 영향을 주는 것으로 관찰되었다. 페놀 제거에 미치는 운전변수의 영향은 각 운전변수가 용존 오존 농도에 미치는 영향과 밀접하게 관련되어 있는 것으로 나타났다. 용존 오존은 높은 pH 조건에서 빠르게 분해되어 페놀과의 반응성이 높은 자유라디칼을 생성시키므로 pH가 증가함에 따라 페놀 제거가 향상되었다. 동일한 pH 조건에서 가스상 오존 농도 및 가스 공급량의 증가는 용존 오존을 증가시킴으로써 페놀 분해를 증진시키는 것으로 나타났다. 메탄올의 주입은 OH 라디칼을 소비시켜 페놀 분해를 방해하는 것으로 관찰되었다.

• 대한환경공학회지
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• 제32권7호
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• pp.649-655
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• 2010

본 연구에서는 난분해성 물질인 페놀을 초음파와 자외선 광선(UV-C)을 이용하여 분해를 알아본 연구이다. 초음파, 자외선, 그리고 초음파와 자외선의 결합반응에서 주파수, 온도, 용액의 pH, 아르곤 가스 purging, 그리고 자외선 세기의 효과를 조사하였다. 초음파 단독 반응의 경우 pH 4, $5^{\circ}C$, 35kHz에서 360분 동안 30%의 페놀의 최적 분해효율을 보였다. 자외선(UV-C) 단독 반응의 경우 $19.3\;mW/cm^2$의 자외선 세기와 pH 4, $5^{\circ}C$에서 60분에 100%의 페놀 분해 효율을 보였다. 이에 반하여 초음파와 자외선의 결합반응에서는 동일 조건에서 45분 동안 페놀이 모두 제거되었다. 초음파와 자외선의 결합 반응에서 페놀은 자외선 강도가 $7.6\;mW/cm^2$일 때 360분 안에 $19.3\;mW/cm^2$일 때는 45분 안에 완전히 분해되었고, 각각의 분해 속도 상수는 $17.3{\times}10^{-3}\;min^{-1}$와 $138.1{\times}10^{-3}\;min^{-1}$이었다. 페놀의 분해반응에서 OH 라디칼의 scavenger로 작용하는 메탄올을 첨가하는 실험을 한 결과 초음파와 자외선 광선의 조합반응에서 페놀 분해의 주요인자는 OH 라디칼이라는 것을 확인할 수 있었다. 페놀 분해의 반응효율 비교는 초음파 + 광반응 조합반응 > 자외선 광선 단독 반응 > 초음파 단독 반응과 같이 확인되었다.

• 유기물자원화
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• 제11권4호
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• pp.130-137
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• 2003

본 연구에서는 페놀에 적응된 미생물을 순수 분리하여 다고리 방향족 탄화수소(PAH)분해에 이용 하고자 하였으며, PAH분해하는 과정에서 나타나는 특성을 파악하고자 하였다. 분리된 미생물은 Stenotrophomonas maltophilia로 동정되었으며, 페놀의 분해경향은 낮은 농도에서 빠른 분해속도 상수값을 가지며, 미생물의 성장률은 0.1447mg cell/mg phenol로 나타났다. 나프탈렌과 페놀의 공존 시 페놀의 분해를 선호하고, 나프탈렌 및 페난스렌을 성장기질로 이용하는 특성을 가지고 있으나, 파이렌과 같이 4개 이상의 고리구조를 가진 PAH의 분해는 이루어지지 않았다. PAH 분해경로는 dioxygenation에 의한 두개의 hydroxy group이 C-1과 C-2에 첨가된 상태에서 ortho cleavage가 일어나고 순차적으로 Decarboxylation이 일어나는 것으로 판단되었다.

• Journal of Microbiology and Biotechnology
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• 제7권1호
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• pp.43-48
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• 1997

Three strains capable of degrading a chlorophenol were isolated by selective enrichment from soils contaminated with industrial wastewater. A Pseudomonas solanacearum TCP114 could use 2,4,6-trichlorophenol (TCP) as sole carbon and energy source, while two strains of Pseudomonas testosteroni CPW301 and Arthrobacter ureafaciens CPR706 could use 4-CP. All isolates also grew well on phenol. The degradation of one component by a pure strain was strongly affected by the presence of other compounds in the medium, CPW301 and CPR706 entirely lost the ability to degrade 4-CP and phenol in the presence of TCP. TCP114 also lost the ability to degrade phenol when 4-CP was added to the culture medium. These restrictions on the degradability could be overcome by employing defined mixed cultures (TCP114 and one strain of 4-CP degrading strains). All three components were successfully degraded by defined mixed cultures through their cooperative activities. It was also demonstrated that defined mixed cultures could be immobilized by using calcium alginate for the semi-continuous degradation of the three component mixture. Immobilization could not only accelerate the degradation rate, but also allowed the reuse of the cell mass several times without loss of the cells' degrading capabilities.

• 한국환경과학회지
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• 제10권5호
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• pp.359-364
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• 2001

Pseudomanas sp. EL-04J was previously isolated from phenol-acclimated activated sludge. This bacterium was capable of degrading phenol and cometabolizing trichloroethylene (TCE). After precultivation in the mineral salts medium containing phenol as a sole carbon source, Pseudomonas EL-04J degraded 90% of TCE $25 \mu\textrm{M}$ within 20 hours. Thus, phenol-induced Pseudomonas sp. EL-04J cells can bdegrade TCE. Followsing a transient lag period, Pseudomonas sp. EL-04J cells degraded TCE at concentrations of at least $250 \mu\textrm{M}$ with no apparent retardation in rate, but the transformance capacity of such cells was limited and depended on the cell concentration. The degradation rate of TCE followed the Michaelis-Menten kinetic model. The maximum degradation ratio ($V_{max}$) and saturation constant ($K_{m}$) were $7nmo {\ell}/min{\cdot}mg$ cell protein and $11 \mu\textrm{M}$, respectively. Cometabolism of TCE by phenol fed experiment was evaluated in $50m {\ell}$ serum vial that contained $10m {\ell}$ of meneral sals medium supplemented with $10 \mu\textrm{M}$ TCE degradation was inhibited in the initial period of 1 mM phenol addition, but after that time Pseudomonas sp. EL-04J cells degraded TCE and showed cell growth.