• Korean Journal of Microbiology
• /
• v.37 no.2
• /
• pp.130-136
• /
• 2001

The killing effects of two types(one-phase reactor and two-phase reactor) of UV-TiO$_2$photocatalytic system on the microorganisms have been studied. The UV-lamp which emits maximum 39 watts at 254 nm was prepared in these system. Three types of $TiO_2$ coating method were adopted. One type is thin film coated form on the quartz tube in the reactor and another one is surface rough coated form on the glass bead. The other one is $TiO_2$-mixed alginate bead form. UV irradiation was carried out for 1 min. In case of one phase reactor, the bactericidal efficiencies of E. coli by $TiO_2$-coated quartz tube and $TiO_2$-coated glass bead were 63.2% and 89.9%, respectively. In the air-bubbling system, the bactericidal efficiency was 95%, however, the efficiency decreased to 90.6% in the non-bubbling system. In the $TiO_2$-mixed alginate bead system, bactericidal efficiency was 86%. When $H_2O$$_2$ was treated (10, 15, 20, and 25 mg/ι) to the $TiO_2$-coated glass bead reactor, bactericidal efficiency significantly increased according to the concentration of $H_2$$O_2$. Two phase reactor showed more elevated efficiency. E. coli was more sensitive to the reaction than S. cerevisiae.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.1
• /
• pp.57-66
• /
• 2003

TiO$_2$ sol was prepared by sol-gel method, and this sol was coated in ceramic and glass bead by dip-coating method. The coated catalyst was applied to degrade benzene in the gas phase by exposing to UV -lamp (365 nm) in a batch reactor. The removal efficiency of the benzene was compared by changing various conditions such as the kind of chemical additives, the coating beads (ceramic and glass), solution pH, the initial concentration of TiO$_2$ sol, UV intensity, and benzene concentration. The physical structure of TiO$_2$ sol used in this study was found to be pu-rely anatase type from XRD analysis. The results showed that ceramic bead was effective as the coating agent rath-er than glass bead. The significant change in the benzene removal efficiency of benzene did not occur with chang-ing coating frequency and the initial concentration of TiO$_2$ sol. The removal efficiency of benzene increased with increasing UV intensity, and with acidic treatment of TiO$_2$-coated ceramic bead.

• Journal of Korean Society on Water Environment
• /
• v.28 no.2
• /
• pp.219-223
• /
• 2012

The fixed solid catalysts such as glass bead, steel mesh, and $TiO_2$ coated ceramic bead were used to investigate effect of radical production at different frequencies. The radical production rate at 300 kHz was faster than that at 35 kHz without solid, but the tendency was changed with the presence of glass bead. The presence of glass beads create non-continuous points between the solid and liquid phases leading to increased formation of cavitation bubbles. However, the radical production decreased when steel mesh was used at 35 kHz although the surface area of contact with liquid was same when glass bead was used. Hence the solid catalyst did not always enhance the radical production. The radical production using $TiO_2$ coated ceramic bead was dramatically increased at 35 kHz due to the breakage of $TiO_2$ coated ceramic bead. Therefore the radical productions at 300 kHz using fixed solid catalysts generally increased while at 35 kHz the results fluctuated according to the experimental conditions.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.564-567
• /
• 2001

Optimal bactericidal conditions of pilot scale UV-$TiO_2$ photoreractor were studied. As the inner diameter of reactor increased. the bactedcidal efficiency decreased. Similarly bactedcidal effect was elevated according to the higher concentration of $TiO_2$. however. the effect was not repressed by the highest concentration(6.000 $mg/{\ell}$)of $TiO_2$ Bactericidal effect of muscovite bead was higher than that of glass bead. When bacterial cells were applied to the photoreacter for 1. 5. and 15 min, bactericidal effects were 62, 94.3. and 99.8%, respectively. When 30 $mg/{\ell}$ of $H_2O_2$ was added to the reaction mixture and sterilized for 5 min, the bactericidal efficiency was 99.8%.

• Korean Journal of Materials Research
• /
• v.32 no.11
• /
• pp.496-507
• /
• 2022

For the selective catalytic reduction of NOx with ammonia (NH₃-SCR), a V₂O₅WO₃/TiO₂ (VW/nTi) catalyst was prepared using V₂O₅ and WO₃ on a nanodispersed TiO₂ (nTi) support by simple impregnation process. The nTi support was dispersed for 0~3 hrs under controlled bead-milling in ethanol. The average particle size (D₅₀) of nTi was reduced from 582 nm to 93 nm depending on the milling time. The NOx activity of these catalysts with maximum temperature shift was influenced by the dispersion of the TiO₂. For the V_0.5W₂/nTi-0h catalyst, prepared with 582 nm nTi-0h before milling, the decomposition temperature with over 94 % NOx conversion had a narrow temperature window, within the range of 365-391 ℃. Similarly, the V_0.5W₂/nTi-2h catalyst, prepared with 107 nm nTi-2h bead-milled for 2hrs, showed a broad temperature window in the range of 358~450 ℃. However, the V_0.5W₂/Ti catalyst (D₅₀ = 2.4 ㎛, aqueous, without milling) was observed at 325-385 ℃. Our results could pave the way for the production of effective NOx decomposition catalysts with a higher temperature range. This approach is also better at facilitating the dispersion on the support material. NH₃-TPD, H₂-TPR, FT-IR, and XPS were used to investigate the role of nTi in the DeNOx catalyst.

• Journal of Environmental Health Sciences
• /
• v.29 no.1
• /
• pp.51-61
• /
• 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.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.9
• /
• pp.939-945
• /
• 2005

The Photocatalytic activity was investigated with the increase of flow rate in a $UV/TiO_2$ packed-bed system. The rate of phenol degradation over $UV/TiO_2$ (dia. = 5 mm) was increased up to 300 mL/min and reached a plateau beyond 400 mL/min. The bead photocatalysts did not exhibit a distinct difference of the phenol degradation rate irrespective of corrosion rates of glass beads and $TiO_2$ coating amounts. Degussa P25 exhibited a higher photocatalytic activity in comparison to other $TiO_2$ sols(Ishihara & N). The performance(activity and durability) of $UV/TiO_2$ packed-bed system can be enhanced by the use of $TiO_2$-coated glass beads instead of granular types that is easily attrited by the shearing force of flowing fluids.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.86.2-86
• /
• 2003

• Journal of the Korean Chemical Society
• /
• v.27 no.4
• /
• pp.273-278
• /
• 1983

With the synthetic standards, valuable metals $(Ta_2O_5, Nb_2O_5, TiO_2, SnO_2$, and $ZrO_2$) in the tin slags have been determined by the x-ray fluorescence spectrometry. The powder sample and the standards are homogeneously mixed with anhydrous $Li_2B_4O_7$ and La_2O_3$ in weight ratio of 15 : 42 : 3 respectively. The mixed material is fused at $1,150^{\circ}C$ for 30 minutes to be changed into the glass bead. The bead is ground to (-) 325 mesh size and pelletized. The analytical results obtained in this work are consistent with the data obtained by other common methods within allowable error range. The standard deviation for $Ta_2O_5$ in PTS-H sample is 0.12 % at level of 3.40 % content.

• Journal of Life Science
• /
• v.21 no.4
• /
• pp.549-553
• /
• 2011

This study was performed to determine whether or not urinary 1-hydroxypyrene (1-OHP) levels can be accurately detected by our 1-OHP-detecting $TiO_2$-Bead-HPLC assay that we developed based on the molecular imprinting method. Our method showed a variation coefficient of 4.97% and a between-day variation coefficient of 4.43%, suggesting that this may be a very stable method. In addition, the recovery rate of 1-OHP from a mixture of 1-OHP and similar substances using our $TiO_2$-Bead-HPLC method was estimated to be 105.6%. The correlation coefficient between the conventional enzyme-HPLC method and this new method was 0.74 (p<0.01) when the urine samples were tested. Based on this result, it is conceivable that our method could be a useful technique for measuring urinary 1-OHP levels. Moreover, our method has some advantages of being easier and less expensive than the conventional method. The results of this study suggest that our method can facilitate the development of a urine 1-OHP sensor using $TiO_2$-coating beads and that development of beads by molecular imprinting can be applied to analysis of chemicals other than 1-OHP.