The composite PAN fibers which incorporated with CNTs and Titania were prepared by mean of wet spinning. These fibers were then pre-oxidized with microwave heating in an air atmosphere. A combination of characterizations was carried out to study the impact of nanoparticles fillers on the properties of as-spun fibers and their performance during the microwave pre-oxidation. The addition of an equal amount of fillers made obvious changes in the chemical and crystalline structure, consequently improves the strength, and this could lower the capability to creep over a wide range of temperatures in the subsequent processes. FTIR and NMR analyses results of the pre-oxidized fibers exhibited clear changes in the PAN structure, where the dehydrogenation reaction and the degree of cyclization were investigated. Additional confirmation of the occurrence of cyclization reaction was achieved by XRD and thermal analysis. According to the TGA results, the pre-oxidized CNT1/ Ti-PAN fibers exhibit greater thermal stability suggesting high carbon content and good quality could result in the dependent carbon fibers.

무지개 빛을 내는 무기진주광택안료는, 내광성, 내용제성 및 내열성 등이 물리적 화학적 안정성이 우수하여 다양한 분야에서 응용되고 있다. 본 연구는 수열합성방법을 사용하여 마이카 티타니아에 파란색 코팅 안료인 염화코발트를 기본으로 화장품 안료로 사용되는 진주광택안료를 합성하였다. 코발트에 의한 안료의 색상을 보완하고자 코발트와 금속 염의 비를 달리하여 안료를 코팅하고, 이를 통해 금속염의 종류에 따라 다양한 색차값을 구현하는 진주광택 안료를 합성하였다. 코발트와 첨가된 금속 염 전구체의 조성비와, 금속 염의 종류에 따라 코팅 특성과 색상을 조절할 수 있었고, 안료의 다양한 색상변화 특성을 색차계를 통해 확인 하였다. 합성된 안료는 SPM, SEM, XRD, EDS 기기를 통해 특성을 분석하였다.

무기안료는 인체에 대한 안정성과 다른 소재와의 상용성이 우수하며, 미적 특성을 감미하기 위한 화장품, 인쇄잉크, 페인트, 건설자재 등 다양한 분야에서 관심 받고 있다. 본 논문에서는 망간과 철이 도핑된 이산화티탄 안료를 합성하기 위하여 수열합성법을 이용하였다. 공정 변수로는 망간 전구체의 양, 철 전구체의 양 및 하소온도 등을 변화시켰다. 제조된 안료의 최적 조건은 망간 전구체의 양이 1.0wt%, 철 전구체의 양이 1.5wt% 그리고 하소온도 550℃일 때였다. 제조된 안료는 XRD, EDS, FE-SEM, Spectrophotometer, UV-Vis Spectrometer 등으로 분석 하였다.

The pearlesent pigment has received attention in a diversity of fields like cosmetics, inks, paints and so on. Ferric Ferrocyanide, one of the nano sized pearlescent pigment, is a kind of surface modification pigment that covers a metal oxidized substance or a coloring agent with uniform thickness. Characteristics of pearlescent pigment are various interference color, intense gloss effect and a three-dimensional effect. We synthesised the pearlesent pigment that ferric ferrocyanide can be deposited on the titania/mica surface by hydrothermal synthesis method. The process parameters are concentration of precursor, controlling pH and reaction temperature. The optimun conditions is that amount of iron(III) chloride hexahydrate is 3.1 wt% and amount of potassim ferrocynide trihydrate is 3.6 wt% in the started pH 4.5 at 70℃. The coating rate and coating efficiency of ferric ferrocyanide was about 1.47 % and 96.7 %, respectively. The synthesised pearlesent pigment was characterized by SEM, XRD, FT-IR and EDS.

본 연구에서는 메조기공 티타니아/알루미나 막을 솔-젤법을 이용하여 제조하였다. 티타니아/알루미나 막의 기공구조 및 결정상은 하소 온도에 따라 조절될 수 있었다. 티타니아에 알루미나를 첨가하는 것은 티타니아 결정상이 아나타제상에서 루타일상으로 상변화 되는 것을 지연시켜 기공구조의 열적 안정화를 가져왔다. 5번 딥코팅하여 제조된 막의 두께는 10.3mum였으며, 평균 기공크기는 5 nm이었다. 기체 투과 실험 결과는 수소와 질소의 permeance는 각각 17.1×10 -7mol/㎡·s·Pa 및 4.7×10 -7mol/㎡·s·Pa이었다. 이 결과는 Knudsen 확산에 의해 설명될 수 있었다.

In this study, we used activated carbon (AC) and titanium oxysulfate as a titanium precursor to prepare carbon/titania composites. We then mixed it with bentonite in different ratios to make a carbon/titania/bentonite monolith for use in architecture bricks by using Phenolic rosin (PR) as a bonding agent. The physicochemical properties of the prepared composites were analyzed by BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), self-cleaning effect and bactericidal tests. The BET surface areas increased as the ratio of carbon/titania composites increased. The SEM microscopy showed that the TiO2 and bentonite were coated on the surface of the AC. The XRD patterns showed a mixture structure of anatase and rutile of TiO2 with a clear SiO2 structure. The EDX spectra of the carbon/titania/bentonite monolith confirmed the presence of various elements, namely C, O, Ti and Si, as well as other, impure elements. Moreover, to determine the self-cleaning effect of the carbon/titania/bentonite monolith, we used methylene blue (MB, C16H18N3S·Cl·3H2O) in an aqueous solution under the irradiation of visible light. Accordingly, all of the samples had excellent degradation of the MB solution. Furthermore, it was observed that the composites with sunlight irradiation had a greater effect on E. coli than any other experimental conditions.

In order to investigate the effect of doping C, N, B and F elements on TiO2 for reducing the band gap, the heat treatment of TiO2 was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase TiO2 was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of TiO2 with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on TiO2 for reducing the band gap effectively.

The field of photocatalysis is one of the fastest growing areas both in research and commercial fields. Titanium dioxide is the most investigated semi-conductor material for the photocatalysis applications. Research to achieve TiO2 visible light activation has drawn enormous attentions because of its potential to use solar light. This paper reviews the attempts made to extend its visible photocatalytic activity by carbon doping. Various approaches adopted to incorporate carbon to TiO2 are summarized highlighting the major developments in this active research field. Theoretical features on carbon doping are also presented. Future scenario in the rapidly developing and exciting area is outlined for practical applications with solar light.

열처리에 따른 함수 티타니아의 구조변화를 X-선 회절, 투과전자현미경, 적외선 흡수 및 라만 분광분석 등을 통하여 조사하였다. 과산화수소와 사염화티타의 혼합용액으로부터 30˚C, pH 9에서 함수 티타니아를 제조하였다. 침전물은 완전하게는 결정화되지 않은 anatase형의 티타니아였다. 700˚C까지 열처리온도가 증가함에 따라 anatase의 결정성은 증가하였으며, 입성자은 높은 온도에서 일어났다. 700˚C에서 anatase로부터 rutile형이 생성되었다.

타이타니움이소프로폭사이드의 가수분해로 타이타니아 졸용액을 제조하고 그 특성을 조사하였다. 용매, 촉매 그리고 물의 양이 졸의 안정도에 미치는 영향을 조?고, 서로 다른 온도에서 졸용액의 전단점도를 측정하여 그 각각의 gel time을 알아보았다. 안정한 조성의 졸용액을 이용하여 광학적으로 투명하고 균일한 타이타니아 박막을 제조할 수 있었다. 또한, 이차비선형 활성단을 도입한 후에도 좋은 박막을 제조할 수 있었다. 제조된 박막은 3~5kV, 50~100˚C 온도범위에서 코로나 분극처리 하였다. 632.8nm He-Ne레이저를 이용하여 측정한 일차 전기 광학 상수, r33는 1.5~5pm/V로서 경시 안정성을 나타내었다.

솔-제법에 의한 고분자솔 제조를 위하여 금속 알콕사이드에 β-diketonate(DKT)기의 유기 리간드를 치환시켜 만든 전구체를 합성한 결과, 가수분해와 축합 반응의 속도 조절이 가능하였고, 이를 이용하여 코팅에 적합한 nm단위의 입자 크기를 갖는 알루미나, 티타니아 솔을 제조하고 그 물성을 파악하였다. 코팅에 적합한 알루미나 솔의 최적조건은 알콕사이드 1몰당 물 1몰, 산 0.3-0.4몰이었다. 티타니아 솔의 제조시는 물/알콕사이드의 몰비가 1이고, 산의 양은 치환수에 따라 달라 1개와 2개 치환된 전구체의 경우 1목의 알콕사이드당 각각 0.25, 0.20몰 이하였다. Dynamic light scattering 장치를 이용하여 제조한 솔의 평균 입자 크기를 측정한 결과 수 nm단위의 미세한 입자를 갖고 있었다. 슬라이드 글라스 위에 코팅하여 450˚C에서 소결한 막을 SEM으로 관찰한 결과 알루미나와 타타니아의 경우 각각 4-4.5μ m, 2-2.5μ m두께의 매끄럽고 균열이 없는 막이 형성되었음을 알 수 있었다. 이때의 입자 크기는 TEM사진을 통하여 알 수 있었으며 티타니아의 경우 수 nm에서 최대 30nm, 알루미나는 1-2nm이하 심지어 수 Å정도의 입자들로 이루어졌음을 관찰하였다. 또한 회절무늬 분석 결과 알루미나는 γ구조, 티타니아는 anastase결정임을 알 수 있었다.

of ordinary Portland cement. Water-cement ratio was 0.40 and cement-sand ratio was 1:3. The content of nano-TiO2 was 3% but the content of nano-SiO2 changed in cement mortars. The content of nano-SiO2 was 0%, 0.5%, 1%, 1.5% and 2% of the binder weight. Mortar prisms and beams were made in specified molds and cured in limewater. Compressive and flexural strengths, porosity and ultrasonic pulse velocity were measured. Then mortars were stored in 6 molar ammonium nitrate (NH4NO3) solution. Leaching depth, variation of mechanical and microstructural properties were measured. Presence of nano-particles decreased the leaching depth and the degradation of mechanical and microstructural properties in mortars.

Graphene oxide (GO)-titania composites have emerged as an attractive heterogeneous photocatalyst that can enhance the photocatalytic activity of TiO2 nanoparticles owing to their potential interaction of electronic and adsorption natures. Accordingly, TiO2-GO mixtures were synthesized in this study using a simple chemical mixing process, and their heterogeneous photocatalytic activities were investigated to determine the degradation of airborne organic pollutants (benzene, ethyl benzene, and o-xylene (BEX)) under different operational conditions. The Fourier transform infrared spectroscopy results demonstrated the presence of GO for the TiO2-GO composites. The average efficiencies of the TiO2-GO mixtures for the decomposition of each component of BEX determined during the 3-h photocatalytic processes were 26%, 92%, and 96%, respectively, whereas the average efficiencies of the unmodified TiO2 powder were 3%, 8%, and 10%, respectively. Furthermore, the degradation efficiency of the unmodified TiO2 powder for all target compounds decreased during the 3-h photocatalytic processes, suggesting a potential deactivation even during such a short time period. Two operational conditions (air flow entering into the air-cleaning devices and the indoor pollution levels) were found to be important factors for the photocatalytic decomposition of BEX molecules. Taken together, these results show that a TiO2-GO mixture can be applied effectively for the purification of airborne organic pollutants when the operating conditions are optimized.

To date, carbon and nitrogen co-doped photocatalysts (CN-TiO2) for environmental application focused mainly on the aqueous phase to investigate the decomposition of water pollutants. Accordingly, the present study explored the photocatalytic performance of CN-TiO2 photocatalysts for the purification of indoor-level gas-phase aromatic species under different operational conditions. The characteristics of prepared photocatalysts were investigated using X-ray diffraction, scanning emission microscope, diffuse reflectance UV-VIS-NIR analysis, and Fourier transform infrared (FTIR) analysis. In most cases, the decomposition efficiency for the target compounds exhibited a decreasing trend as input concentration (IC) increased. Specifically, the average decomposition efficiencies for benzene, toluene, ethyl benzene, and xylene (BTEX) over a 3-h process decreased from 29% to close to zero, 80 to 5%, 95 to 19%, and 99 to 32%, respectively, as the IC increased from 0.1 to 2.0 ppm. The decomposition efficiencies obtained from the CN-TiO2 photocatalytic system were higher than those of the TiO2 system. As relative humidity (RH) increased from 20 to 95%, the decomposition efficiencies for BTEX decreased from 39 to 5%, 97 to 59%, 100 to 87%, and 100 to 92%, respectively. In addition, as the stream flow rates (SFRs) decreased from 3.0 to 1.0 L min-1, the average efficiencies for BTEX increased from 0 to 58%, 63 to 100%, 69 to 100%, and 68 to 100%, respectively. Taken together, these findings suggest that three (IC, RH, and SFR) should be considered for better BTEX decomposition efficiencies when applying CN-TiO2 photocatalytic technology to purification of indoor air BTEX.

Catalytic activities of V2O5/TiO2 catalyst were investigated under reaction conditions such as reaction temperature, catalyst size, inlet concentration and space velocity. A 1,2-dichlorobenzene(1,2-DCB) concentrations were measured in front and after of the heated V2O5/TiO2 catalyst bed, and conversion efficiency of 1,2-DCB was determined from it's concentration difference. The conversion of 1,2-DCB using a pellet type catalyst in the bench-scale reactor was lower than that with the powder type used in the micro flow-scale reactor. However, when the pellet size was halved, the conversion was similar to that with the powder type catalyst. The highest conversion was shown with an inlet concentration of 100 ppmv, but when the concentration was higher or lower than 100 ppmv, the conversion was found to decrease. Complete conversion was obtained when the GHSV was maintained at below 10,000 h-1, even at the relatively low temperature of 250°C. Water vapor inhibited the conversion of 1,2-DCB, which was suspected to be due to the competitive adsorption between the reactant and water for active sites.

카올리나이트(kaolinite) 분말의 티타니아(Titania, TiO2) 포팅을 위한 출발물질로서 인도네시아산 카올리나이트와 티타늄-아이소프로폭사이드(titanium isopropoxidc, TIP)가 사용되었으며, 실험은 졸-겔법(sol-gel method)으로 수행되었다. 또한 강매로서 에탄올이, 가수분해 반응을 위해 물이 사용되었으며 촉매로서 염산을 첨가하였다. 카올리나이트 분말의 소성여부에 따른 영향을 검토하기 위해 카올리나이트와 메타카올리나이트(metakaolinite)를 대상으로 각각 실험하였으며, 반응 혼합물의 몰비, 교반시간, 숙성시간, 결정화 시간과 온도의 변화에 따른 티타니아 결정도를 검토하였다. 실험조건 TIP 0.1 몰(mol), 물 0.15 몰, 염산 0.005 몰, 에탄을 100 ml, 카올리나이트 50 g, 교반 4시간, 숙성 24시간, 결정화온도 1050℃, 결정화 2시간에서 가장 높은 아나타제 결정도 17.61%를 나타냈다. 결정화온도의 변화에 따른 아나타제 결정도 분석결과, 카올리나이트와 메타카올리나이트 분말에 코팅된 티타니아는 1050℃와 1200℃에서 각각 37.61%, 17.39%로 최고의 결정도가 관찰되었다. 즉, 카올리나이트 분말에 코팅된 티타니아가 메타카올리나이트에 비해 더 낮은 온도에서 더 높은 결정도를 나타냈다.