• 한국응용과학기술학회지
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• 제23권2호
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• pp.153-159
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• 2006

The photocatalytic degradation of methylene blue(MB) was investigated using $TiO_2$ as photocatalyst and UV radiation. $TiO_2$ supported with activated carbon(AC) was prepared by SOL-GEL method and depended on several parameters such as the mass ratio of $TiO_2/AC$, pH and experimental time. The presence of the anatase and rutile crystal phase was determined by XRD analyses of the prepared $TiO_2$. The degradation of MB with $TiO_2/AC$ was about 20% higher than that of AC alone. A variation of photodegradation was negligible under UV radiation conditions ( ${\geq}$ 40W). It was experimentally showed that the photodegradation rate was increased with increasing the amount of photocatalyst. The optimal catalyst was prepared by impregmation of $5wt%-TiO_2$ with AC and was calcined at $300^{\circ}C$, and showed about 99% removal efficiency for 3hrs.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.486-496
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• 2018

Bimetallic Pd@Ni nanostructure exhibited enhanced co-catalytic activity for the selective hydrogenation of benzaldehyde compare to their monometallic counterparts. Impregnation of these mono/bimetallic nanostructures on mesoporous $TiO_2$ leads to several surface modifications. The bimetallic PNT-3 ($Pd_3@Ni_1/mTiO_2$) exhibited large surface area ($212m^2g^{-1}$), and low recombination rate of the charge carriers ($e^--h^+$). The hydrogenation reaction was analyzed under controlled experiments. It was observed that under UV-light irradiations and saturated hydrogen atmosphere the bimetallic PNT-3 photocatalyst display higher rate constant $k=5.31{\times}10^{-1}h^{-1}$ owing to reduction in the barrier height which leads to efficiently transfer of electron at bimetallic/$mTiO_2$ interface.

• Korean Chemical Engineering Research
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• 제51권2호
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• pp.195-202
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• 2013

본 연구에서는 Titanium(IV) sulfate($Ti(SO_4)_2$)와 암모니아수로부터 수열합성법을 이용하여 비교적 낮은 합성온도($80{\sim}100^{\circ}C$)와 상압에서 소성과정을 거치지 않고 $TiO_2$ 분말을 제조하였고, $TiO_2$ 제조 시 반응온도, 반응물의 초기농도, 혼합용액의 pH와 같은 반응조건에 따른 $TiO_2$ 입자의 결정구조와 입자분포, 형상 등과 같은 물리적 특성을 고찰하였다. 제조한 시료는 UV 조사 하에 Brilliant Blue FCF(BB-FCF)의 광분해 실험을 실시하여 광분해 성능과 DRS 분석을 통해 광촉매 활성을 비교하였다. 제조한 시료의 물성은 XRD, SEM, PL, 입도분포 측정을 통하여 확인하였다. Titanium(IV) sulfate($Ti(SO_4)_2$)의 초기농도가 증가할수록 $TiO_2$의 평균 입자크기와 결정화도는 증가하였고 광촉매 활성은 감소하였다. 혼합용액의 pH가 높을수록 평균 입자크기는 감소하였고 광촉매 활성은 증가하였다. 반응온도가 높을수록 결정화도와 광촉매 활성은 증가하였다. 이상의 결과들로부터 $Ti(SO_4)_2$와 암모니아수를 이용한 비교적 낮은 합성온도와 상압에서의 수열합성법으로도 순수한 anatase 결정구조의 $TiO_2$가 제조됨을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1105-1113
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• 2004

Disinfection of a waterborne pathogenic protozoa, Giardia lamblia, by the conventional chlorine method has been known to be difficult. An alternative disinfection has been carried out by using a UV -light illuminating optical­fiber photoreactor. Light intensity diffused from one piece of a clad-removed optical-fiber was $1- 1.5{\mu}Em^{-2}s^{-1}$. Disinfection capability in a UV -light irradiated optical-fiber reactor suspended with 0.01 g $TiO_{2}\;dm^{-3}$ was 1.4 times that in the same reactor without $TiO_{2}$ photocatalysts. To resolve the absorption and scattering of UV light by the particles themselves as well as the difficulty of recycling particles in the slurry­type reactor, $TiO_{2}$ which was obtained by a hydrothermal method, was immobilized on clad-removed optical fibers. Such pretreatment of fiber surface resulted in an excellent transparency, which enhanced the UV light to diffuse laterally from a fiber surface. Coating time of the prepared solution by the hydrothermal method was not effective after more than two times. Disinfection capability in the $TiO_{2}$-immobilized optical-fiber reactor was $83\%$ in 1 h at $40^{\circ}C$, which was slightly higher than $76\%$ at $22^{\circ}C$ and $68\%$ at $10^{\circ}C$. Disinfection capability at $22^{\circ}C$ increased from $74\%$ at an initial pH of 3.4, through $76\%$ at pH 6.5, to $87\%$ at an initial pH of 10. Oxygen supply with air-flow rate of 5 $cm^3\;min^{-1}$ did not seem to increase the disinfection capability with UV /immobilized $TiO_2$.

• 한국세라믹학회지
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• 제45권11호
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• pp.651-657
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• 2008

In this study, CNT/$TiO_2$ composites were prepared using surface modified Multiwall carbon nanotube (MWCNT) and titanium n-butoxide (TNB) with benzene. The composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), FT-IR spectra, and UV-vis absorption spectroscopy. The UV radiation induced photoactivity of the CNT/$TiO_2$ composites was tested using a fixed concentration of methylene blue (MB, $C_{16}H_{18}N_3S{\cdot}Cl{\cdot}3H_2O$) in an aqueous solution. Finally, it can be considered that the MB removal effect of the CNT/$TiO_2$ composites is not only due to the adsorption effect of MWCNT and photocatalytic degradation of $TiO_2$, but also to electron transfer between MWCNT and $TiO_2$.

• 대한환경공학회지
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• 제27권10호
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• pp.1129-1135
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• 2005

한강에서 추출한 휴믹물질의 산화를 위해 회전 반응기를 도입하였다. $TiO_2$ 광촉매의 혼합을 위해 사용되는 공기는 UV 램프와 광촉매 사이에서 UV 조사를 방해할 수 있으므로, 더 나은 UV 조사율을 위해 반응기 내부에 배플이 설치된 회전 반응기를 고안하였다. FT-IR, $^{13}C$-NMR의 분석 결과, 한강 휴믹물질은 다른 상용화된 휴믹물질과는 다른 특성을 보여주었다. XAD-7HP 수지로 분리된 한강 휴믹물질을, 반응 후 광촉매의 분리 및 회수문제를 해결하기 위해, $TiO_2$를 hollow bead에 고정화한 광촉매와 UV-A, UV-C 램프를 사용하여 광촉매산화시켰다. 초기 휴믹물질의 TOC 농도가 5 mg/L일 때, 초기 pH 3, $TiO_2$ 주입률 2.0 g/L을 최적 조건으로 결정하였다. 또한 UV-C와 UV-A 램프의 비교실험을 수행한 결과, 비슷한 TOC 제거율을 보였다. 하지만, 분자량 분포 실험 결과, UV-A 램프보다 UV-C 램프로 광촉매산화시킨 것이 상대적으로 저분자량 부분이 증가하였다.

• 한국환경보건학회지
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• 제29권1호
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• pp.51-61
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• 2003

Pollution purification using titanium dioxide (TiO$_2$) photocatalyst has attracted a great deal of attention with increasing number of relent environmental problems. Currently, the application of TiO$_2$ photocatalyst has been focused on purification and treatment of waste water. However. the use of conventional TiO$_2$ powder photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we herein studied the pilot-scale design to aid in optimization of the energy-saving process for more through development and reactor design by solar light/UV lamp/ TiO$_2$system. In this study, we manufactured the TiO$_2$sol by sol-gel method. According to analysis by XRD, SEM and TEM, characterization of TiO$_2$ sol were nano-size (5-6 nm) and anatase type. Inorganic binder (SiO$_2$) was added to TiO$_2$ lot to be coated for support strongly, and support of ceramic bead was used to lower separation rate that of glass bead The influences were studied of various experimental parameters such as TiO$_2$ quantity, pH, flow rate. additives, pollutants concentration, climate condition and reflection plate by means of reaction time of the main chararteristics of the obtained materials. In water treatment system, variable realtor as solar light/ or UV lamp according to climate condition such as sunny and cloudy days treated the phenol and E-coli(Escherichia coli) effectively.

• 멤브레인
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• 제4권3호
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• pp.152-162
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• 1994

광촉매 $TiO_2$ 막에 의한 formic acid의 광분해 효율이 연구되었다. 막반응기는 용액의 정밀여과(micro-filtration)는 물론 유기물의 광분해를 동시에 수행할 수 있도록 다공성 $TiO_2$ 튜브 (평균기공: $0.2{\mu}m$)를 이용한 새로운 타입으로 개발되었으며 광원으로는 365 nm 파장을 갖는 UV를 사용하였다. 또한 반응기의 광분해 효율을 증진시키기 위하여 슬립케스팅법으로 제조한 $TiO_2$ 튜브표면을 $TiO_2$ 졸로 코팅하였다. $TiO_2$ 막 반응기의 분해효율은 용액의 투과량(flux), 막의 미세구조(졸의 pH), 공급산소량, $H_2O_2$와 같은 1차 산화제(primary oxidants)의 첨가 그리고 $Nb_2O_5$와 같은 물질의 도핑(doping)에 매우 민감함을 알 수 있었다. 최적의 광분해 반응조건에서 formic acid의 산화효율은 pH가 1.45인 $TiO_2$ 졸로 코팅한 막 반응기를 사용했을때 80% 이상이었다. Formic acid 용액에 1차 산화제 $H_2O_2$를 첨가하거나 막을 $Fe_2O_3$로 도핑함으로써 산화효율은 최고 20%까지 증가시킬 수 있었다.

• 한국결정성장학회지
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• 제11권5호
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• pp.231-237
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• 2001

Etch rates up to 120 nm/min for $Ta_{2}O_{5}$ were achieved in both $SF_{6}/Ar$ and $Cl_{2}/Ar$ discharges. The effect of ultraviolet (UV) light illumination during ICP etching on $Ta_{2}O_{5}$ etch rate in those plasma chemistries was examined and UV illumination was found to produce significant enhancements in $Ta_{2}O_{5}$ etch rates most likely due to photoassisted desorption of the etch products. The effects of ion flux, ion energy, and plasma composition on (Ba, Sr)$TiO_3$ etch rate were examined and maximum etch rate ~90 nm/min was achieved in $Cl_{2}/Ar$ ICP discharges while $CH_{4}/H_{2}/Ar$ chemistry produced extremely low etch rates (${\leq}10\;nm/min$) under all conditions.

• 공업화학
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• 제9권5호
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• pp.634-638
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• 1998

응집이 없는 단분산의 $PMSQ/TiO_2$ 복합 미립자를 얻기 위하여 300 nm 크기의 $TiO_2$ seed가 분산되어 있는 메탄올 수용액과 MTMS (Methyltrimethoxysilane)를 메탄올에 녹인 용액을 혼합하여 $TiO_2$ seed 표면에서 MTMS가 가수분해 및 축합 반응이 일어나도록 유도하여 복합 미분말을 제조하였다. 촉매로 암모니아를 사용하였고, 반응온도는 실온이었으며, 모든 반응은 질소분위기에서 행하였다. 교반속도, 반응온도, $[H_2O]/[MTMS]$, $[MTMS]/[TiO_2]$ 등을 변화하여 입자의 크기 및 형태에 영향을 주는 인자들을 조사한 결과, [MTMS]=0.2 M, $[NH_4OH]=0.6M$, $[H_2O]/[MTMS]=100$, $[MTMS]/[TiO_2]=10-50$이고 실온에서 서서히 교반한 경우 단분산된 약 $1-2{\mu}m$의 크기를 갖는 복합입자를 얻을 수 있었다. 얻어진 입자에 대한 소수성을 물에 대한 접촉각 측정을 통해 조사한 결과 거의 180도에 가까운 접촉각을 보임으로써 복합입자의 소수성이 매우 뛰어남을 확인할 수 있었다. 자외선 차폐효과도 UV 투과도 측정을 통해 조사되었다.