• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.339-347
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• 2012

This study focuses on developing catalysts for the removal of toluene produced from paint booth. Toluene is one of the major VOC in painting, coating process. Pd catalysts have been used in hydrogenation oxidation and low temperature combustion reaction for toluene removal. Pd catalysts, even though it is very precious and expensive. Therefore, the prepared catalysts from minimizing the amount of Pd ratio (0.1~1.0wt%) were measured. As a result, 1.0wt% Pd(R) catalyst under all conditions showed the highest activity. These results may suggest that the catalytic activity is related to Pd dispersion according sintering atmosphere and Pd ratio in the manufacturing process through the analysis of SEM, XRD.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.47-54
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• 1996

UASB reactor was operated for treating wastewater containing high sulfate to assess their performance, competition between sulfate-reducing bacteria(SRB) and methane-producing bacteria(MPB), and the change in the characteristics of microbial granules according to change of hydraulic retention time(HRT) in the reactor. The reactor was fed with a synthetic moderate strength wastes(glucose, 2000 mgCOD/l) containing high sulfate($2400mgSO_4{^{2-}}/l$). The organic loading rate(OLR) ranged from 1.5 to 3.0 gCOD/l.d as HRT maintained 15 to 30 hrs in the stage I. The COD removal efficiency was between 80 to 92%. During this period, methane yield rapidly decreased from 0.3 to 0.1 1 $CH_4$/gCODremoved. While sulfide concentration in the effluent increased from 80 to 200 mgS/l. This indicates that SRB becomes dominant over MPB at a relatively long HRT in the excess sulfate. When OLR of reactor maintained from 5 to 8 gCOD/l.d in the stage II, methane yield increased from 0.1 to 0.17 1 $CH_4$/gCODremoved regardless of decrease of COD removal efficiency. This indicates that SRB is more sensitive to the change of a short HRT than MPB. In the competition between SRB and MPB, about 30% of the removed COD was utilized by SRB at HRT of 30 hrs during the start-up period, while about 73% was used by SRB at HRT of 15hrs at the final step of second experimental stage. Whereas after shock exposure of OLR about 62% was utilized by SRB at HRT of 5hrs. It indicates that SRB is strongly suppressed by the wash-out of significant dispersed SRB since a large electron flow is distributed to the MPB. In addition, the granulation in the presence of high sulfate is unfavoured at a long HRT because of substrate transport limitations into MPB like Methanothrix spp. which is an important factor in the composition of the granules. Accordingly, granule sizes in the UASB reactor decreased with time due to weak network frame of granules by the decreased activity of MPB.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2613-2616
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• 2009

FeOOH/$TiO_2$, a heterojunction structure between FeOOH and $TiO_2$, was prepared by covering the surface of the $\sim$100-nm-sized FeOOH particles with Degussa P25 by applying maleic acid as an organic linker. Under visible light irradiation (${\lambda}{\geq}$ 420 nm), FeOOH/$TiO_2$ showed a notable photocatalytic activity in removal of gaseous 2-propanol and evolution of $CO_2$. It was found that FeOOH reveals a profound absorption in the spectral range of 400 - 550 nm, and its valence band (VB) level is located relatively lower than that of $TiO_2$. The considerable photocatalytic efficiency of the FeOOH/$TiO_2$ under visible light irradiation was therefore deduced to be caused by the hole transfer between the VB of FeOOH and $TiO_2$.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.54-60
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• 1999

Three different types of lab-scale anaerobic bioreactors, AF and two-stage ASBF-PR and ASBF-SP, were evaluated in treating swine wastewater by operating at $1{\sim}2$ days of hydraulic retention time with increasing organic loading rate upto 6.3 $kg-COD/m^3{\cdot}d$ at $35^{\circ}C$. Seeding the anaerobic bioreactors with waste anaerobic digester sludge from a municipal wastewater treatment plant was effective and a 40-day acclimation period was required for steady-state operation. Three anaerobic bioreactors were effective in treating swine wastewater with COD removal efficiency of $66.4{\sim}84.9$% and biogas production rate of $0.333{\sim}0.796m^3/kg-COD_{removed}{\cdot}d$. Increases of organic loading rate by increasing influent COD concentration and/or decreasing hydraulic retention time caused decreases in COD removal efficiency and increases in biogas production rate. At relatively high organic loading rate employed in this study, the treatment efficiency of AF and ASBF-PR were similar but superior than that of ASBF-SP, indicating that porosity and pore size of the media packed in the bioreactors are more important factors contributing the performance of to bioreactors than specific surface area of the media. TKN in swine wastewater must be removed prior to the anaerobic processes when anaerobic process is considered as a major treatment process since influent TKN concentration of $1,540{\sim}1,870mg/L$ to the bioreactors adversely affect the activity of methanogenic bacteria, resulting in decreases of treatment efficiency and biogas production rate by 50%.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.6-13
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• 2011

In this study, we used activated carbon (AC) and charcoal (CH) as carbon sources with $TiO_2$ powder to prepare spherical carbons containing titania (SCCT) by using phenolic resin (PR) as a bonding agent. The physicochemical characteristics of the SCCT samples were examined by BET, XRD, SEM, EDX, iodine adsorption and compressive strength. The photocatalytic activity was evaluated by measuring the removal efficiency of three kinds of organic dyes: methylene blue (MB), methyl orange (MO) and rhodamine B (Rh.B) under a UV/SCCT system. In addition, evaluation of chemical oxygen demand (COD) of piggery waste was done at regular intervals and gave a good idea about the mineralization of wastewater.

• Journal of Life Science
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• v.12 no.5
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• pp.584-588
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• 2002

Asymmetric enantioselective resolution system using epoxide hydrolase activity of Aspergillus niger LK was developed and operated for the production of optically pure styrene oxide. Two-phase hollow-fiber reactor system was employed for the enhanced solubility of racemic styrene oxide in organic phase and protection of epoxide hydrolase activity in aqueous phase. For the removal of phenyl-1,2-ethandiol, the inhibitor of epoxide hydrolase, cascade hollow-fiber reactor system was also developed. Chiral (S)-styrene oxide (39 mM in dodecane) could be asymmetrically resolved with high enantiopurity (> 99% ee) using these reactor system.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1803-1808
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• 2008

For practical application, the stability of permeabilized Ochrobactrum anthropi SY509 needs to be increased, as its half-life of enzymatic denitrification is only 90 days. As the cells become viable after permeabilization treatment, this can cause decreased activity in a long-term operation and induce breakage of the immobilization matrix. However, the organic solvent concentration causing zero cell viability was 50%, which is too high for industrial application. Thus, whole-cell immobilization using glutaraldehyde was performed, and 0.1% (v/v) glutaraldehyde was determined as the optimum concentration to maintain activity and increase the half-life. It was also found that 0.1% (v/v) glutaraldehyde reacted with 41.9% of the total amine residues on the surface of the cells during the treatment. As a result, the half-life of the permeabilized cells was increased from 90 to 210 days by glutaraldehyde treatment after permeabilization, and no cell viability was detected.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.189-203
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• 2015

Membrane biofouling impedes wide application of membrane bioreactor (MBR) for wastewater treatment. Recently, quorum sensing (QS) mechanisms are accounted for one of major mechanisms in biofouling of MBRs. In this study, vanillin was applied to investigate reduction of biofouling in MBRs. MBR sludge was analyzed to contain QS signal molecules by cross-feeding biosensor assay and HPLC. In addition, the inhibitory activity of vanillin against bacterial quorum sensing was verified using an indicator strain CV026. The vanillin doses greater than 125 mg/L to 100 mL of MBR sludge showed 25% reduction of biofilm formed on the membrane surfaces. Two MBRs, i.e., a typical MBR as a control and an MBR with vanillin, were operated. The TMP increases of the control MBR were more rapid compared to those of the MBR with the vanillin dose of 250 mg/L. The treatment efficiencies of the two MBRs on organic removal and MLSS were maintained relatively constant. Extracellular polymeric substance concentrations measured at the end of the MBR operation were 173 mg/g biocake for the control MBR and 119 mg/g biocake for the MBR with vanillin. Vanillin shows great potential as an anti-biofouling agent for MBRs without any interference on microbial activity for wastewater treatment.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.137-143
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• 2021

Most cervical cancers are associated with high-risk human papillomavirus (HPV) infection. Currently, cervical cancer treatment entails surgical removal of the lesion, but treatment of infection and preventing tissue damage are issues that still remain to be addressed. Herbal medicine and biological studies have focused on developing antiviral drugs from natural sources. In this study, we analyzed the potential antiviral effects of Pinus densiflora Sieb. et Zucc. leaf extracts against HPV. The pine needle extracts from each organic solvent were analyzed for antiviral activity. The methylene chloride fraction (PN-MC) showed the highest activity against HPV pseudovirus (PV). The PN-MC extract was more effective before, rather than after treatment, and therefore represents a prophylactic intervention. Mice were pre-treated with PN-MC via genital application or oral administration, followed by a genital or subcutaneous challenge with HPV PV, respectively. The HPV challenge results showed that mice treated via genital application exhibited complete protection against HPV. In conclusion, PN-MC represents a potential topical virucide for HPV infection.

• Journal of Environmental Science International
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• v.21 no.8
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• pp.989-996
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• 2012

Nitrate contamination of water environments can create serious problems such as eutrophication of rivers. Conventional biological processes for nitrate removal by heterotrophic denitrification often need additional organic substrates as carbon sources and electron donors. We tried to accelerate biological denitrification by using bioelectrochemical reactor (BER) in which electrode works as an electron donor. Denitrification activity of 8 environmental samples from various sediments, soils, groundwaters, and sludges were tested to establish an efficient enrichment culture for BER. The established enrichment culture from a soil sample showed stable denitrification activity without any nitrite accumulation. Microbial community analysis by using PCR-DGGE method revealed that dominant denitrifiers in the enrichment culture were Pantoea sp., Cronobacter sakazakii, and Castellaniella defragrans. Denitrification rate ($0.08kg/m^3{\cdot}day$) of the enrichment culture in BER with electrode poised at -0.5 V (vs Ag/AgCl) was higher than that ($2.1{\times}10^{-2}kg/m^3{\cdot}day$) of BER without any poised potential. This results suggested that biological denitrification would be improved by supplying potential throughout electrode in BER. Further research using BER without any organic substrate addition is needed to apply this system for bioremediation of water and wastewater contaminated by nitrate.