• 생명과학회지
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• 제9권5호
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• pp.581-589
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• 1999

This study was carried out to compare ozonation with photocatalysis degradation for removal Geosmin of algae byproduct. The change of pH was decresed from 7.02 to 2.8 after contact time 480 minute for ozonation. In case of UV-germicidal lamp, pH was very quickly increased from 7.02 to 7.5, but Halogen lamp did very slowly change pH. Geosmin degradation ratio was as following, UV-germicidal lamp/TiO2(100mg/L) O3>UV-germicidal lamp/TiO2(50mg/L)>UV-germicidal lamp(10W)>halogen lamp(50W). Instead of TiO2 suspension solution, Geosmin degradation ratio was very low using hollow bead and pellet as coated TiO2. As a result of identifing byproducts, ozonation generated three species of aldehyde such as 3-Heptanone and three species of alcohol such as Heptanal, but photocatalysis formed 1, 14-Tetradecanediol infinitesimally.

• 펄프종이기술
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• 제40권5호
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• pp.53-59
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• 2008

This study was carried out to investigate the effect of photocatalysis using $TiO_2$ and UV applied for the COD reduction of wastewater in linerboard mill. Trials were done to obtain the optimum addition amounts of $TiO_2$ and $H_2O_2$ to the wastewater and find an appropriate pH condition for photocatalysis on $TiO_2$ for degrading COD. The photocatalytic reaction was applied to the wastewater collected after secondary activated sludge treatment in WWTP of linerboard mill. The optimum application of photocatalysis reaction was obtained under the addition conditions of 2 g/L of $TiO_2$ and 200 mg/L of $H_2O_2$ at pH 3.0, respectively. The removal efficiency of $SCOD_{Cr}$ by photocatalytic treatment was 86.4 % and higher than Fenton treatment in which removal efficiency was 67.4 %. It was concluded that the photocatalytic process using $TiO_2$ and UV could be applied to the wastewater treatment in linerboard mill and also to the dramatic drop-off in NBDCOD load from wastewater of tertiary treatment in WWTP.

• 한국물환경학회지
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• 제21권3호
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• pp.263-266
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• 2005

Comparison between photocatalysis (UV+$TiO_2$) and sonophotocatalysis (Sonication+UV+$TiO_2$) were performed in lab-scale experiments for the treatment of chloroform. The effect of operational parameters, i.e., initial chloroform concentration, $TiO_2$ concentration, UV light intensity and sonication time on the degradation rate of aqueous solution of chloroform has been examined. The optimal conditions for photocatalysis and sonophotocatalysis processes were determined: initial chloroform concentration was 25 mg/L, the concentration of $TiO_2$ was 200 mg/L and UV light intensity was $6.630 mW/cm^2$, respectively. The optimal sonication time on sonophotocatalysis process was 90 min. Under the optimal conditions, sonophotocatalysis was effective for inducing faster degradation of the chloroform.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E1호
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• pp.19-26
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• 2006

The decomposition of gaseous $CH_3CHO$ was investigated by metal loaded $TiO_2$ (pure $TiO_2,\;Pt/TiO_2,\;Pd/TiO_2,\;Mn/TiO_2\;and\;Ag/TiO_2$) with $UV/TiO_2$ process and $UV/TiO_2/O_3$ process at room temperature and atmospheric pressure. Metal loaded $TiO_2$ was prepared by photodeposition. Decomposition of $CH_3CHO$ was carried out in a flow-type photochemical reaction system using three 10W black light lamps ($300{\sim}400nm$) as a light source. The experimental results showed that the degradation rate of $CH_3CHO$ was increased with Pt and Ag on $TiO_2$ compared to pure $TiO_2$, but decreased with depositing Pd and Mn on pure $TiO_2$. The considerable increase in the degradation efficiency of the $CH_3CHO$ was found by a combination of photocatalysis and ozonation as compared to only by ozonation or photocatalysis. Loading of Pt on $TiO_2$ promoted conversion of gaseous ozone. The degradation rate of gaseous $CH_3CHO$ decreased with an increase of water vapor in the feed stream for the both $UV/TiO_2\;and\;UV/TiO_2/O_3$ processes. The pure $TiO_2$ was more affected by the water vapor than Pt loaded $TiO_2$.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1895-1899
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• 2012

$SiO_2$-coated $TiO_2$ composite materials with enhanced photocatalytic activity under UV light was prepared by a simple catalytic hydrolysis method. XRD, TEM, UV-vis spectroscopy, Photoluminescence, FT-IR and XP spectra were used to characterize the prepared samples. The obvious shell-core structure was shown for obtained $SiO_2$@$TiO_2$ sample. The average thickness of the $SiO_2$ coating layer was 2-3 nm. The interaction between $SiO_2$ and $TiO_2$ restrained the recombination of excited electrons and holes. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under UV light. The photocatalytic activity of $SiO_2$@$TiO_2$ was much higher than that of P25 and mechanical mixing sample $SiO_2/TiO_2$. The possible mechanism for the photocatalysis was proposed.

• 대한환경공학회지
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• 제31권10호
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• pp.927-932
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• 2009

난분해성 및 독성 폐수 처리는 고급산화 기술과 생물학적 처리가 친화결합(intimate coupling) 을 이룰 때 최적의 효과를 거둘 수 있다. 본 연구에서는 광촉매 산화와 생물학적 처리를 친화결합하도록 고안된 다공성 $TiO_2$ 코팅 담체를 제조하여 광촉매 반응에 관한 동력학 연구를 수행하였다. 저온 sol-gel 코팅법으로 제조된 PVA 재질의 다공성 $TiO_2$ 담체는 UV 조사하에서 methylene blue (MB)를 효율적으로 분해하였다. 시험 농도(최대 100 ${\mu}M$)에서 MB의 흡착속도는 1차반응 (first-order reaction)의 성질을 보였으며, 흡착과 산화를 포함한 총반응속도는 유사 Langmuir 모델로 예측 가능하였다. 이러한 원인은 담체 표면에 MB가 흡착됨에 따라 UV 조사에 의하여 광촉매 반응이 일어날 표면이 줄어들었기 때문인 것으로 판단된다. 다공성 $TiO_2$ 담체의 단위 $TiO_2$ 량당 최대 MB 제거속도는 슬러리 $TiO_2$ 반응기에서 얻은 MB 제거속도보다 4배 더 빨랐다. 본 연구로 인하여 저온 sol-gel 코팅법으로 제조한 PVA 재질 다공성 $TiO_2$ 담체가 성공적인 광분해 반응을 나타내는 것이 확인되었으며, 동 담체에 대한 광촉매 반응의 동력학적 성질이 구명되어, 향후 생물처리를 친화결합 시킬 수 있는 연구 바탕을 확보하였다.

• Advances in environmental research
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• 제3권1호
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• pp.11-28
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• 2014

Advanced oxidation processes using UV and catalysts like $TiO_2$ and ZnO have been recently applied for the photocatalytic degradation of MTBE in water. Attempts have been made to replace the UV radiation by the solar spectrum. This review intends to shed more light on the work that has been done so far in this area of research. The information provided will help in crystallizing the ideas required to shift the trend from UV photocatalysis to sunlight photocatalysis. The careful optimization of the reaction parameters and the type of the dopant employed are greatly responsible for any enhancement in the degradation process. The advantage of shifting from UV photocatalysts to visible light photocatalysts can be observed when catalysts like $TiO_2$ and ZnO are doped with suitable metals. Therefore, it is expected that in the near future, the visible light photocatalysis will be the main technique applied for the remediation of water contaminated with MTBE.

• 대한토목학회논문집
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• 제26권3B호
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• pp.321-327
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• 2006

본 연구는 축산폐수처리를 위해 광촉매의 적용가능성과 처리효율 및 범위를 실험하여 축산폐수처리에 대한 기초 자료로 제시하고자 한다. 축산폐수처리에 대한 광촉매양의 증가는 높은 처리효율을 나타냈으며 알카리 영역에서 보다 산성영역 특히 pH3에서 축산폐수처리 효과는 우수하게 나타났다. 또한 광촉매양의 증가에 따라 색도 보다는 $TCOD_{Mn}$의 제거가 빠르게 이루어 졌다. UV 또는 $TiO_2$를 단독으로 사용하여 폐수처리를 하였을 때 보다 $UV/TiO_2$를 함께 적용하였을 때가 처리효율은 우수하게 나타났으며 산화제로 과산화수소를 주입하였을 때 처리효율은 $UV/TiO_2$만을 적용하였을 때 보다 처리효율이 우수하게 나타났다. 본 실험에서의 과산화수소 적정 주입량은 200 mg/L이며 과산화수소 적정주입량이 보다 많이 주입되었을 때는 처리효율이 떨어지는 것으로 나타났다. 또한 과산화수소의 주입량은 실험 시 계속적으로 주입이 되어야 높은 처리효율을 얻을 수 있었다.

• Advances in environmental research
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• 제2권4호
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• pp.261-277
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• 2013

The degradation of alachlor has been investigated using sonolysis (US), photocatalysis (UV) and sonophotocatalysis (US/UV) using three photocatalyst viz. $TiO_2$ (mixture of anatase and rutile), $TiO_2$ (anatase) and ZnO. The effect of photocatalyst loading on the extent of degradation of alachlor has been investigated by varying $TiO_2$ (both types) loading over the range of 0.01 g/L to 0.1 g/L and ZnO loading over the range of 0.05 g/L to 0.3 g/L. The optimum loading of the catalyst was found to be dependent on the type of operation i.e., photocatalysis alone or the combined operation of sonolysis and photocatalysis. All the combined processes gave complete degradation of alachlor with maximum rate of degradation being obtained in the case of sonophotocatalytic process also showing synergistic effect at optimized loading of photocatalyst. About 50% to 60% reduction in TOC has been obtained using the combined process of sonophotocatalysis depending on the operating conditions. The alachlor degradation fitted first order kinetics for all the processes under investigation. It has been observed that the $TiO_2$ (mixtrure of anatase and rutile) is the most active photocatalyst among the three photocatalysts studied in the current work. The effect of addition of radical enhancers and scavengers on sonophotocatalytic degradation of alachlor has been investigated in order to decipher the controlling mechanism. The alachlor degradation products have been identified using LC-MS method.

• 한국물환경학회지
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• 제20권5호
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• pp.488-493
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• 2004

The effects were examined from several conditions of $TiO_2$ photocatalysis reaction to phenols degradation by changing it's reacting conditions such as phenol concentration, pH, $TiO_2$ concentration, $H_2O_2$ concentration, flow rate, and intensity of ultraviolet rays. Phenol degradation was more efficient in low concentration of phenol, neutral pH. Phenol degradation appeared to increase as concentration of $TiO_2$ photocatalyst, that of $H_2O_2$ and intensity of ultraviolet rays increased. As $TiO_2$ dosage increased, initial rate constant k linearly increased. When $H_2O_2$ was injected more than optimum, phenol removal rate didn't increase in proportional to the change of $H_2O_2$ concentration as OH radicals was being consumed. When flow rate is less than $4.75m^3/m^2$ day, phenol removal efficiency appeared to decrease as ultraviolet rays transmission rate becomes low by $TiO_2$ suspension coated in photo reaction column. Meanwhile, initial rate constant according to light intensity change in less than $25mW/cm^2$ appeared to be in proportion to light intensity ($mW/cm^2$) Removal efficiency decreased about 12% after 180 minutes of reaction time while showed stable removal efficiency of 100% after 300 minutes when using regenerated $TiO_2$.