• Journal of environmental and Sanitary engineering
• /
• v.14 no.4
• /
• pp.21-28
• /
• 1999

This study was carried out the simultaneous removal or organics and Cr(VI) in aqueous suspensions of phtocatalyst under circular type reactor and UV light illumination. In this experiment, comparison on the removal of Cr(VI) by photoreduction using UV light, photocatalyst adsorption using TiO2, ZnO, and FeCl3 as photocatalyst, and phtocatalysis using UV light with photocatalysts as well as the effect of experimental parameters such as phtocatalyst dosage, a kinds of organics and their concentration was examined. The major results of this study were as follows; 1. It was found that photocatalyst adsorption and phtocatalysis were applicable to the removal of Cr(VI), and Cr(VI) was more effectively eliminated by TiO2 than ZnO, and FeCl3. 2. phtocatalytic removal efficiency of Cr (VI) increased with increasing phtocatalyst dosage. However, over 1.0g/l of phtocatalyst dosage, the efficiency reached a plateau. 3. phtocatalytic removal of Cr(VI) was enhanced by addition of organics such as salicylic acid, mandelic acid, EDTA, and citric acid, and phtocatalytic oxidation of organics were also observed. 4. It was found that the simultaneous removal of organics and Cr(VI) using phtocatalysis was possible.

• Carbon letters
• /
• v.16 no.4
• /
• pp.247-254
• /
• 2015

To improve photocatalytic efficiency, graphene/Ag/TiO₂ nanotube catalyst was synthesized, and its surface characteristics and photocatalytic activity investigated. For deposition of Ag nanoparticles on the TiO₂ nanotubes, a polymer compound containing CH₃COOAg/poly(L-lactide) was utilized, and the silver particles were precipitated by reducing the silver ions during the annealing process. Graphene deposition on the Ag/TiO₂ nanotubes was achieved using an electrophoretic deposition process. Based on the dye degradation results, it was determined that the photocatalytic efficiency was significantly affected by deposition of silver particles and graphene on the TiO₂ catalyst. Highly efficient destruction of the dye was obtained with the new graphene/Ag/TiO₂ nanotube photocatalyst. This may be attributed to a synergistic effect of the graphene and Ag nanoparticles on the TiO₂ nanotubes.

• Journal of the Korean Ceramic Society
• /
• v.26 no.3
• /
• pp.323-330
• /
• 1989

Wear restance titanium carbonitride (TiCN) films were deposited on the SKH9 tool steels and WC-Co cutting tools by plasma assisted chemical vapor deposition (PACVD) using a gaseous mixture of TiCl4, CH4, N2, H2 and Ar. The effects of the deposition temperature and RF(Radio Frequency) power on the deposition rate, chlorine content and crystallinity of the deposited layer were studied. The experimental results showed that the stable and adherent films could be obtained above the deposition temperature of 47$0^{\circ}C$ and maximum deposition rate was obtained at 485$^{\circ}C$. The deposition rate was much affected by RF power and maximum at 40W. The crystallinity of the deposited layer was improved with increasing the deposition temperature and RF power. The TiCN films deposited by PACVD contained much chlorine. The chlorine content in the TiCN films was affected by deposition conditions and decreased with improving the crystallinity of the deposited layer. The deposited TiCN films deposited at the deposition temperature of 52$0^{\circ}C$ and RF power of 40W had an uniform surface with very fine grains of about 500$\AA$ size. The microhardness of the deposited layer was 2,300Kg/$\textrm{mm}^2$.

• Carbon letters
• /
• v.8 no.3
• /
• pp.214-224
• /
• 2007

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 $TiO_2$ 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 $TiO_2$ 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.

• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.1
• /
• pp.90-98
• /
• 2002

In this paper, the annealing heat treatments for the best corrosion resistant of Ti(Grade 2) were studied in a 3.5% NaCl solution by electrochemical methods. The annealing heat treatments were accomplished at 650, 700 and $750^{\circ}C$ with different time of 30min., 1hour and 2 hours in a vacuum condition. The obtained results are: 1) in the case of solution heat treated $930^{\circ}C$ for 2 hours in a vacuum and air, the corrosion potentials were -348.7 and -567. 1mV, and current densities 2.32 and $22.62\mu\textrm{A}$, respectively, 2) as increase both annealing heat treatment temperature 650, 700, $750^{\circ}C$ and time 30min., 1 hour, 2 hours, the corrosion potential were decreased, whereas corrosion current density increased, 3) in the case of cyclic polarization, the measured charges were increased as increasing solution heat treatment temperature and time, 4) on the bases of corrosion potential, current density and charge, the best annealing temperature and time were measured as $700^{\circ}C$ and 30min. for Ti(Grade 2) material.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2008.02a
• /
• pp.378-378
• /
• 2008

• Applied Chemistry for Engineering
• /
• v.3 no.1
• /
• pp.46-52
• /
• 1992

$TiO_2/SO_4{^{2-}}$ was prepared by precipitation from the mixed solution of titanium chloride and hydrochloric acid followed by modification with sulfuric acid. The characterization of prepared catalyst was performed by using IR, XPS, XRD and DT-TGA. Infrared spectra of $TiO_2/SO_4{^{2-}}$ showed bidentate sulfate ion coordinated to the surface of $TiO_2$. The acid strength of modified catalyst was at least $H_0{\leq}-14.52$, showing the superacidic properties which are attributed to the double bond nature of S=O of the complex formed by the interaction of $TiO_2$ with sulfate ion. For $TiO_2/SO_4{^{2-}}$, the specific surface area increased and the transition from the amorphous to anatase phase occurred at a higher temperature, as compared with pure $TiO_2$.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.10
• /
• pp.1664-1670
• /
• 2018

Titanium dioxide ($TiO_2$) has wide applications in food, cosmetics, pharmaceuticals and manufacturing due to its many properties such as photocatalytic activity and stability. In this study, the biosynthesis of $TiO_2$ nanoparticles (NPs) was achieved by using Baker's yeast. $TiO_2$ NPs were characterized by X-ray Diffraction (XRD), UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray analysis (EDX) studies. The XRD pattern confirmed the formation of pure anatase $TiO_2$ NPs. According to EDX data Ti, O, P and N were the key elements present in the sample. SEM and TEM revealed that the nanoparticles produced were spherical in shape with an average size of $6.7{\pm}2.2nm$. The photocatalytic activity of $TiO_2$ NPs was studied by monitoring the degradation of methylene blue dye when treated with $TiO_2$ NPs. $TiO_2$ NPs were found to be highly photocatalytic comparable to commercially available 21 nm $TiO_2$ NPs. This study is the first report on antimicrobial study of yeast-mediated $TiO_2$ NPs synthesized using $TiCl_3$. Antimicrobial activity of $TiO_2$ NPs was greater against selected Gram-positive bacteria and Candida albicans when compared to Gram-negative bacteria both in the presence or absence of sunlight exposure. $TiO_2$ NPs expressed a significant effect on microbial growth. The results indicate the significant physical properties and the impact of yeast-mediated $TiO_2$ N Ps as a novel antimicrobial.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.30 no.2
• /
• pp.181-187
• /
• 2004

Preparations of mesoporous materials using various templates and their applicability have been intensively investigated for many years. We studied on synthesizing mesoporous Ti02 with pores in which sensitive compounds having weak physico-chemical properties such as thermal or UV irradiation and low solubility in solvent are trapped. Prior to trapping OMC in the pores of mesoporous titania, OMC was nano-emulsified in O/W system using Lecithin. Thereafter the OMC was trapped in the pores of mesoporous titania using sol-gel method. Main focus of this work is to prepare OMC-trapped mesoporous titania and to trace the stability and solubility of nano-emulsified OMC in the pores of mesoporous titania, and compared with that of mesoporous silica. OMC-trapped mesoporous Inorganic-Organic hybrid titania showed higher factors in sun protecting and a skin penetration phenomenon was reduced.

• Korean Journal of Materials Research
• /
• v.19 no.3
• /
• pp.142-150
• /
• 2009

In this paper, non-treated ACF (Activated Carbon Fiber) /$TiO_2$ and Zn-treated ACF/$TiO_2$ were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/$TiO_2$ composite contained only typical single and clear anatase forms while the Zn-treated ACF/$TiO_2$ contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the $ZnCl_2$ concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/$TiO_2$ composites. The prominent photocatalytic activity of the Zn-treated ACF/$TiO_2$ can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-$TiO_2$ and Zn-ACF.