• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.184-187
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• 2004

고급산화법 중 하나인 광촉매인 TiO$_2$를 이용한 시스템은 300~400nm 파장의 UV영역에서 비교적 적은 에너지로 유기 오염 물질을 $CO_2$와 $H_2O$로 산화시킨다[1]. 따라서 폐수용액 중 오염물질을 제거한 경우에도 슬러리로 인한 2차 오염의 문제가 없다. 최근에는 난분해성 물질이나 독성을 가진 물질을 포함된 폐수처리 시설의 고도처리를 위하여 분리막을 도입하는 추세이다.(중략)

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.103-111
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• 2000

Ozonation and advanced oxidation($H_2O_2/O_3$) process were investigated under various experimental conditions to improve the efficiency of biological filter used for the treatment of recycled wastewater from aquaculture. Ammonia removal followed the first-order reaction whose reaction rate constant(k) was $2.0{\times}10^{-2}min^{-1}$ in ozonation. The ammonia removal rate increased according as the bicarbonate alkalinity is increased. About 46% $NH_3$ was oxidized by ozone at 200 mg/L as $CaCO_3$. When alkalinity existed in wastewater, ammonia removal rate by advanced oxidation was very low due to the inhibition effect of bicarbonate. However, when initial pH was adjusted to about 8.2 by 0.1 N KOH, ammonia removal rate was improved higher than that by ozonation. Especially. ammonia removal rate was the highest at $H_2O_2/O_3$ of 0.25 and about 90% of ammonia was removed in 30 min at this ratio as pH was maintained over 9. In the case of wastewater containing ammonia and organic constituents, ammonia removal efficiency by both ozonation and advanced oxidation decreased seriously because organic constituents consumed the oxidant faster than ammonia. In addition the optimal $H_2O_2/O_3$ ratio was changed. Like ammonia removal, DOC(dissolved organic carbon) increased for first 10 min and then decreased slowly because the particulate organic constituents were oxidized rapidly and then produce DOC. Even when the ammonia concentration by twice, oxidation of DOC was not retarded.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.77-77
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• 2003

산업화에 따라 각종 산업분야에서 유기 용제의 사용이 증가하게 되었고 대기오염, 수질오염 등의 상태가 심각해져가고 있는 실정이다 그러나 다양해진 오염물질을 처리하는 데 있어서 기존의 산화처리방법은 한계에 달하였고 새로운 처리공정으로 최근 고급산화법(AOP : Advanced Oxidation Process)에 대한 연구가 활발하게 진행되고 있다. 이에 본 연구에서는 대기환경 및 인체에 심각한 영향을 주는 VOCs(Voletail Organic compounds)중 BTEX(Benzene, Toluene, Ethylbenzene, Xylene)를 다양한 형태의 광촉매제를 이용하여 기상 광분해한 후 이에 대한 최적의 분해 조건과 분해율을 비교하고자 하였다. 순환식의 자체 제작한 기상광반응장치를 이용하여, CVD법으로 TiO$_2$ 입자를 알루미나 비드위에 코팅한 볼과 같은 방법으로 유리기판위에 코팅한 판상의 광촉매제 그리고 결정성이 각기 다른 루틸상과 아나타제 그리고 아나타제/루틸 혼합상의 TiO$_2$ 분말을 직접 이용하여 VOCs 농도와 종류, 광원의 종류 및 세기를 변화시켜 PID(Photo ionization Detector)방식의 순환식 VOCs 측정기를 이용하여 광분해율을 실시간으로 측정하였다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.437-438
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• 2016

• Journal of Wetlands Research
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• v.13 no.3
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• pp.697-705
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• 2011

The aim of this study was to examine ozonation disinfection efficiency for Escherichia coli DH5alpha removal, containing the multi-resistance plasmid pB10 as well as chlorination disinfection efficiency. In addition, plasmid pB10 removal rates were estimated by ozonation and chlorination. The removal efficiency of pB10 via ozonation was about 2 to 4 times higher than chlorination. High removal efficiency of pB10 is likely due to OH radical produced during ozonation. These results suggest that integration of advanced oxidation process such as ozonation (or photocatalytic oxidation) with conventional disinfection such as chlorination may be needed for effective control of antibiotic resistant bacteria and genetic materials.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.64-72
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• 1996

The effect of $O_3$, $O_3/pH$, and $O_3/H_2O_2$, $O_3/UV$, and $H_2O_2/UV$ advanced oxidation process(AOP) were investigated for the treatment of tetrachloroethylen(PCE) at various condition. The removal efficiency of 10, 20, and 30ppm PCE by ozonation were almost same, only about 60%. And pseudo first-order rate constants, ko for overall oxidation was about 0.097($min^{-1}$). In the $O_3/pH$ AOP experiment for the 20ppm PCE, the removal rate of PCE increased with the increase of pH. However, mineralization rate of PCE at pH 7 was higher than at pH 10. In the $O_3/H_2O_2$ AOP, the removal rate of PCE was the highest at peroxide-to-ozone dosage ratio of about 0.9, which PCE was removed over 99.95%. Despite 42% of PCE was directly photolyzed by the UV irradiation, the removal efficiency of PCE by $O_3/UV$ AOP was only about 70%. In $H_2O_2/UV$ AOP, the removal efficiency of PCE increased to about 98% in proportion to the $H_2O_2$ injection concentration at constant UV intensity of 5W/l.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.144-150
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• 2013

Hybrid ceramic membrane (HCM) processes that combined ozonation with a ceramic membrane (CM) or a reactive ceramic membrane (RM), an iron oxide nanoparticles (IONs) incorporated-CM were investigated for membrane fouling control. Alumina disc type microfiltration and ultrafiltration membranes doped with IONs by sintering method were tested under varying mass fraction of IONs. Scanning electron microscope (SEM) images showed that IONs were well-doped on the CM surface and doped IONs were approximately 50 nm in size. Change in the pure water permeability of RM was negligible compared to that of CM. These results indicate that IONs incorporation onto CM had little effect on CM performance in terms of the flux. Natural organic matter (NOM) fouling and fouling recovery patterns during HCM processes confirmed that the RM-ozonation process enhanced the destruction of NOM and reduced the extent of fouling more than the CM-ozonation process by hydroxyl radical formation in the presence of IONs on RM. In addition, analyses of NOM in the feed water and the permeate showed that the efficiency of membrane fouling control results from the NOM degradation during HCM processes; leading to removal and transformation of relatively high contents of aromatic, high molecular weight and hydrophobic NOM fractions.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.731-741
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• 2004

The purpose of this study was to evaluate the potential of a gamma ray irradiation to decompose hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in an aqueous solution. The decomposition reaction of RDX by gamma ray irradiation was a first-order kinetic over the applied initial concentrations (10-40mg/L). The dose constant was strongly dependent on the initial concentration of the RDX. The removal of RDX was more efficient at pH below 3 and at pH above 11 than at neutral pH (pH 5-9). The required irradiation dose to remove 99% of the RDX (40mg/L) was 4, 8 and 1 kGy, at pH 2, 7 and 13, respectively. The dose constant was increased by two folds and over twelve folds at pH 2 and 13, respectively, when compared with that at pH 7. When an irradiation dose of 20 kGy was applied, the removal efficiencies of TOC were 80, 57 and 91% at pH 2, 7 and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of RDX and formic acid was detected as an organic byproduct. The results showed that a gamma ray irradiation was an attractive method for the decomposition of RDX in an aqueous solution and it was found that a strong alkaline pH over 12 should be applied to the decomposition reaction of RDX.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.927-932
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• 2009

Toxic and recalcitrant organic pollutants in wastewaters can be effectively treated when advanced oxidation and biodegradation are combined, ideally with intimate coupling, in which both processes occur simultaneously in the same system. One means to achieve intimate coupling is to coat nanoscale $TiO_2$ on the outside of macroporous biofilm carriers. This study investigated the kinetics of photocatalysis with $TiO_2$-coated porous carriers. The carriers were made of polyvinyl alcohol (PVA) and coated with $TiO_2$ using a low-temperature sol-gel process. The $TiO_2$-coated carriers catalyzed the oxidation of methylene blue (MB) effectively under irradiation of UV light. The overall reaction rate with adsorption and photolysis saturated at high MB concentration, and approached the adsorption rate, which was first order for all MB concent rations. This result indicates that adsorbed MB may have slowed photocatalysis by blocking active sites for photocatalysis. The overall kinetics could be described by a quasi-Langmuir model. The estimated maximum specific (per unit mass of $TiO_2$) transformation rate of MB by the $TiO_2$-coated carriers was four times larger than that obtained from slurry-$TiO_2$ reactors. This observation demonstrated that the $TiO_2$ present as a coating on the carriers maintained high efficiency for transforming recalcitrant organic matter via photocatalysis. These findings serve as a foundation for advancement of an intimate coupling of photocatalysis to biodegradation.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.567-573
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• 2012

Compared with the natural marble, the artificial marble has the advantages of excellent appearance, high degree of finish, even color, fine pressure and wear resistance, bear erosion and weathering, etc. It can be widely used in kitchen countertops, bath vanity tops, table tops, furniture, reception desks, etc. However, large amounts of artificial marble waste such as scraps or dust have been generated from sawing and polishing processes in artificial marble industry. Waste from artificial marble industry is increasing according to demand magnification of luxurious interior material. Artificial marble wastes can be recycled as aluminum oxide used as raw materials in electronic materials, ceramics production, etc., and methyl methacrylate(MMA) which become a raw material of artificial marble by pulverization, pyrolysis and distillation processes. The characteristics of artificial marble wastes was analyzed by using TGA/DSC and element analysis. Crude aluminum oxide was obtained from artificial marble waste by pulverization and thermal decomposition under nitrogen atmosphere. In this work, Box-Behnken design was used to optimize the pyrolysis process. The characteristics of crude aluminum oxide was evaluated by chromaticity analysis, element analysis, and surface area.