• Journal of Industrial Technology
• /
• v.27 no.A
• /
• pp.15-18
• /
• 2007

This study investigated disinfection effect by general water purifier and water purifier with UV light disinfection. The results are as follows : (i) The general bacteria existed plentifully in a storage tank before treatment (ii) Water treated in water purifier did not meet the water treatment regulation standard since the presence of bacteria, whereas with UV light application the regulation standard is totally satisfied. (iii) Photocatalytic disinfection process with UV light in the presence of $TiO_2$ more effectively killed general bacteria than UV light only.

• Economic and Environmental Geology
• /
• v.50 no.3
• /
• pp.215-224
• /
• 2017

Arsenic (As) is known to be the most toxic element and frequently detected in groundwater environment. Inorganic As exists as arsenite [As(III)] and arsenate [As(V)] in reduced and oxidized environments, respectively. It has been reported that the toxicity of arsenite is much higher than that of arsenate and furthermore arsenite shows relatively higher mobility in aqueous environments. For this reason, there have been numerous researches on the process for oxidation of arsenite to arsenate to reduce the toxicity of arsenic. In particular, photooxidation has been considered to be simple, economical, and efficient to attain such goal. This study was conducted to evaluate the applicability of naturally-occurring goethite as a photocatalyst to substitute for $TiO_2$ which has been mostly used in the photooxidation processes so far. In addition, the effects of several factors on the overall performance of arsenite photocatalytic oxidation process were evaluated. The results show that the efficiency of the process was affected by total concentration of dissolved cations rather than by the kind of those cations and also the relatively higher pH conditions seemed to be more favorable to the process. In the case of coexistence of arsenite and arsenate, the removal tendency by adsorption onto goethite appeared to be different between arsenite and arsenate due to their different affinities with goethite, but any effect on the photocatalytic oxidation of arsenite was not observed. In terms of effect of humic acid on the process, it is likely that the higher concentration of humic acid reduced the overall performance of the arsenite photocatalytic oxidation as a result of competing interaction of activated oxygen species, such as hydroxyl and superoxide radicals, with arsenite and humic acid. In addition, it is revealed that the injection of oxygen gas improved the process because oxygen contributes to arsenite oxidation as an electron acceptor. Based on the results of the study, consequently, the photocatalytic oxidation of aqueous arsenite using goethite seems to be greatly feasible with the optimization of process.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.203-203
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.04a
• /
• pp.205.1-205
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.141.2-141
• /
• 2003

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2000.11a
• /
• pp.42-42
• /
• 2000

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2004.11a
• /
• pp.3-8
• /
• 2004

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1998.11a
• /
• pp.83-83
• /
• 1998

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.272-276
• /
• 2005

Food wastewater derived from three-stages methane fermentation system showed high concentrations of sCOD, T-N and $NH_{3}-N$. To treat the organic wastewater, the optimal operating conditions for high efficiency $UV/TiO_{2}$ photocotalytic system have been investigated. In the first process, wastewater was pre-treated with $FeCl_{3}. The optimum pH and concentration for coagulation were 4.0 and 2000 mg/L, respectively. Through this process, 52.6% of $COD_{cr}$ was removed. The second process was $UV/TiO_{2}$ photocatalytic reaction. The optimum conditions for the operation of $UV/TiO_{2}$ photocatalytic system developed in this lab have been studied. In this process, CODcr was removed from 2890 to 184 mg/L and T-N was removed from 2496 to 914 for 24 hours, respectively.

• Journal of Welding and Joining
• /
• v.21 no.4
• /
• pp.46-55
• /
• 2003

TiO$_2$-WO$_3$(8.2wt%) coatings were prepared by the APS (Atmospheric Plasma Spraying) process to clarify the relationship between the process parameters(H$_2$ gas flow rate of plasma 2nd gas and spraying distance) of the APS coating and photo-decomposition efficiency kinetics of the MB(methylene blue) aqueous solution decomposition and to understand the effect of addition of WO$_3$ on photocatalytic properties of TiO$_2$ sprayed coating. Further, the temperature and velocity of flying particles were measured by DPV-2000 to investigate the relationship between microstructure of coatings and process parameters. Properties of coatins were investigated by XRD, SEM, XPS, RAMAN, UV/VIS spectrometer. In case of the TiO$_2$-WO$_3$(8.2wt%) coating, it had a lower anatase fraction than that of pure-TiO$_2$ coatings because of flying in the higher temperature plasma plume by the heavy weight of TiO$_2$, WO$_3$. And, when WO$_3$ added powders were spayed, the doping effects of W ions substituted into the Ti ion sites was not occured during melting and solidification cycles of spraying. It was found that the addition of WO$_3$ was ineffective effective on increasing photo-decomposition efficiency of TiO$_2$ sprayed coating.