• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.592-592
• /
• 2013

We synthesized BiOI nanostructures with various doped-concentrations of Ag (0.1, 1.0, 5.0, 10.0 mol%) and Ti (1.0, 5.0, 10.0, 30.0, 50.0 mol%). They show spherical echinoid-like structures examined by scanning electron microscope. The BET surface areas were measured to be in the range of 40~70 $m^2$/g, which is reduced by doping. The indirect band gap was estimated to be 1.8 eV for undoped BiOI with no change and 1.0 eV increase upon Ag and Ti doping, respectively. The structures were further examined by X-Ray diffraction analysis, FT-IR, and photoluminescence. We also demonstrated adsorption and photocatalytic degradation performances for methyl orange and Rhodamine B on the echinoid-like BiOI structures.

• Advances in nano research
• /
• 제3권2호
• /
• pp.67-79
• /
• 2015

Air stable nanoparticles were prepared from cobalt sulphate using tetra butyl ammonium bromide as surfactant and sodium borohydride as reductant at room temperature. The cobalt nanocolloids in aqueous medium were found to be efficient catalysts for the degradation of toxic organic dyes. Our present study involves degradation of Methylene Blue and Rhodamine-B using cobalt nanoparticles and easy recovery of the catalyst from the system. The recovered nanoparticles could be recycled several times without loss of catalytic activity. Palladium nanoparticles prepared from palladium chloride and the same surfactant were found to degrade the organic dyes effectively but lose their catalytic activity after recovery. The cause of dye colour discharge by nanocolloids has been assigned based on our experimental findings.

• 대한기계학회논문집B
• /
• 제24권10호
• /
• pp.1399-1408
• /
• 2000

A 2-dimensional temperature field measurement technique using PLIF (Planar Laser Induced Fluorescence) was developed and it was applied to an axisymmetric buoyant jet. Rhodamine B was used as a fluorescent dye. Laser light sheet illuminated a two-dimensional cross section of the jet. The intensity variations of LIF signal from Rhodamine B molecules scattered by the laser light were captured with an optical filter and a CCD camera. The spatial variations of temperature field of buoyant jet were derived using the calibration data between the LIF signal and real temperature. The measured results show that the turbulent jet is more efficient in mixing compared to the transition and laminar jet flows. As the initial flow condition varies from laminar to turbulent flow, the entrainment from ambient fluid increases and temperature decay along the jet center axis becomes larger. In addition to the mean temperature field, the spatial distributions of temperature fluctuations were measured by the PLIF technique and the result shows the shear layer development from the jet nozzle exit.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_4호
• /
• pp.157-164
• /
• 2001

The performance of fluidized-bed reactor with Photomedia, immobilized TiO$_2$ onto the porous ceramic ball using a sol-gel method has been studied in this work. A simple model substrate, dilute Rhodamine B (RhB), was decolorized at room temperature. For the purpose of comparison, the slurry reactor and the Inner Wall Coated Reactor (IWCR) were used. The aim of this work was to develop the photocatalytic fluidized bed reactor (PFBR) through contrasting the photodegradability of various reactors such as the TiO$_2$slurry reactor, the inner-wall coated reactor (IWCR). In this study, the RhB was decolorized in three types of reactor. Even though the reaction rate constant of PFBR was lower than that of slurry reactor, PFBR had the advantages of preventing the wash-out of photocatalyst, so it can be operated continuously.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2014년도 추계학술대회 논문집
• /
• pp.256-257
• /
• 2014

The effects of the preparation conditions of ZnO-modified TaON on the photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light were investigated. The ZnO/TaON nanocomposite were prepared by loading particulate $Ta_2O_5$ with ZnO using different ZnO contents, followed by thermal nitridation at 1123 K for 5 h under $NH_3$ flow (20 ml min.1). The asprepared samples were characterized by XRD, UV-Vis-DRS, and SEM-EDX. The results revealed that the band gap energy absorption edge of as prepared nanocomposite samples was shifted to a longer wavelength as compared to ZnO and $Ta_2O_5$, and the 60 wt% ZnO/TaON nanocomposite exhibited the highest percentage (99.2 %) of degradation of Rh. B and the highest reaction rate constant ($0.0137min^{-1}$) in 4 h which could be attributed to the enhanced absorption of the ZnO/TaON nanocomposite photocatalyst. Hence, these results suggest that the ZnO/TaON nanocomposite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial ZnO, $Ta_2O_5$, and TaON.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_3호
• /
• pp.149-155
• /
• 2001

In recent years, rapid technological advances in the textile and dyeing industry have yielded benefits to society but have also generated new and significant environmental problems. The treatment alternatives applicable for the removal of color vary, depending upon the type of dye wastewater Advanced oxidation processes are considered to provide more permanent merits. One of these oxidation treatments attracting much attention is photocatalytic oxidation, which uses TiO$_2$ due to its non-toxic, insoluble liquid as well as a highly reactive nature under UV irradiation. This study sets out to demonstrate the effect of photocatalyst dosage, dye concentrations, pH and light intensity on color removal efficiency under aerobic conditions. The results of this study show Rhodamine B(RhB) was not decolorized when a dye solution was exposed only to air or treated by TiO$_2$ only In the presence of both TiO$_2$ and UV light, however, the presence of RhB decreased up to 95 % within 60minutes. The more addition TiO$_2$ and the more diluted dye solution, showed a higher removal rate.

• 한국환경과학회지
• /
• 제27권7호
• /
• pp.611-620
• /
• 2018

In this study, a metal-organic framework (MOF) material $NH_2$-MIL-101(Fe) was synthesized using the solvothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-visible spectrophotometry, field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and surface area measurements. The XRD pattern of the synthesized $NH_2$-MIL-101(Fe) was similar to the previously reported patterns of MIL-101 type materials, which indicated the successful synthesis of $NH_2$-MIL-101(Fe). The FT-IR spectrum showed the molecular structure and functional groups of the synthesized $NH_2$-MIL-101(Fe). The UV-visible absorbance spectrum indicated that the synthesized material could be activated as a photocatalyst under visible light irradiation. FE-SEM and TEM images showed the formation of hexagonal microspindle structures in the synthesized $NH_2$-MIL-101(Fe). Furthermore, the EDS spectrum indicated that the synthesized material consisted of Fe, N, O, and C elements. The synthesized $NH_2$-MIL-101(Fe) was then employed as an adsorbent and photocatalyst for the removal of Indigo carmine and Rhodamine B from aqueous solutions. The initial 30 min of adsorption for Indigo carmine and Rhodamine B without light irradiation achieved removal efficiencies of 83.6% and 70.7%, respectively. The removal efficiencies thereafter gradually increased with visible light irradiation for 180 min, and the overall removal efficiencies for Indigo carmine and Rhodamine B were 94.2% and 83.5%, respectively. These results indicate that the synthesized MOF material can be effectively applied as an adsorbent and photocatalyst for the removal of dyes.

• 공업화학
• /
• 제26권6호
• /
• pp.714-718
• /
• 2015

$PbMoO_4$ 및 $PbMo_{1-x}Cr_xO_4$ 산화물을 수열합성법으로 합성하여 XRD, DRS, Raman, SEM 및 PL 등에 의해 특성분석을 하였고, 자외선 및 가시광 조사 하에서 rhodamine B의 광분해 반응에서의 활성을 조사하였다. XRD 및 Raman의 분석 결과로부터 대부분의 촉매들은 크롬이온의 첨가와 무관하게 잘 결정화된 $PbMoO_4$ 구조를 가지고 있었으며 51에서 59 nm의 크기를 나타내었다. $PbMo_{1-x}Cr_xO_4$ 산화물의 DRS 곡선은 가시광 영역으로 강한 흡수선을 나타내었다. $PbMoO_4$ 산화물은 가시광 조사 하에서 낮은 광촉매 활성을 나타내었으나 크롬이온의 첨가량이 증가할수록 활성이 증가하였다. 모든 촉매들은 540-580 nm 부근에서 강하고 넓은 PL 흡수밴드가 나타났으며, 이 피크의 세기가 커질수록 광분해 활성이 증가하는 것으로 나타났다.

• Applied Biological Chemistry
• /
• 제37권5호
• /
• pp.343-348
• /
• 1994

A. tumafaciens C58로부터 $^3H-thymidine$으로 표지한 Ti plasmid를 분리하여 lyophilization-rehydration법으로 octadecyl rhodamine B로 표지한 liposome에 내포시켰다. Liposome조제에 사용한 지질은 phosphatidylserine(PS)을 사용한 PS liposome과, PS와 cholesterol(Chol)을 같은 mole비로 섞은 PS-Chol이었다. 꽃담배 원형질체는 0.1% macerozyme과 1.5% cellulase를 처리하여 유리시키고 불연속성 농도구배 원심분리로 정제하였다. $^3H-Ti plasmid$를 포함하고 있는 liposome$(1\;{\mu}mole\;PS)$을 5 mM $Ca^{2+}$과 10% PEG로 처리하여 꽃담배 원형질체$(10^6)$과 융합시켰다. 원형질체와 융합한 liposome의 양은 rhodamine B의 형광으로 측정하고 원형질체에 도입된 Ti plasmid의 양은 tritium의 방사능으로 측정하였다. 이때 PS liposome에서는 7.9%가 PS-Chol liposome에서는 7.2%의 liposome이 원형질체와 융합하였는데 융합과정에서 PS liposome서는 약 60%의 내용물이 유실되었고 PS-Chol liposome에서는 약 30%의 내용물이 유실되었다. 따라서 Ti plasmid를 식물원형질체에 도입하는데는 PS 보다는 PS-Chol로 구성된 liposome이 효율적인 것으로 나타났다. PS-Chol liposome을 사용할 경우에 1개의 원형질체에 약 1,700개의 Ti plasmid가 결합하고 있음으로 lyophilization-rehydration법을 사용하여 Ti plasmid를 식물원형질체에 도입할 경우에 식물의 형질전환 효율을 높일 수 있을 것임을 시사하여 준다.

• Bulletin of the Korean Chemical Society
• /
• 제33권9호
• /
• pp.2910-2916
• /
• 2012

Cadmium sulphide (CdS) nanorods were prepared by a single precursor thermal decomposition (SPTD) method. The formation of CdS nanorods and their structure, morphology and elemental composition were studied by means of FT-IR, XRD, FE-SEM, HR-TEM and EDAX analysis. Photoluminescence (PL) and lifetime measurements were recorded to study the luminescence properties of the material. The PL spectrum of the CdS nanorods showed one broad peak and four shoulders and the cause for this emission was discussed. The PL emissions from the band edge and deep trap state of the CdS nanorods were studied by lifetime measurements. Further, the synthesized CdS nanorods showed an increase in efficiency of photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The increase in the photocatalytic activity was attributed to the mixed phase of the CdS nanorods.