• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.368-371
• /
• 2003

Accidental release of petroleum products from underground storage tank(USTs) is one of the most common causes of groundwater contamination. BTEX is the major components of fuel oils, which are hazardous substances regulated by many nations. In addition to BTEX, other gasoline consituents such as MTBE(methyl-t-buthyl ether), anphthalene are also toxic to humans. Natual attenuation processes include physic, chemical, and biological trasformation. Aerobic and anaerobic biodegradation are believed to be the major processes that account for both containment of the petroleum-hydrocarbon plum and reduction of the contaminant concentrations. Aerobic bioremediation has been highly effective in the remediation of many fuel releases. However, Bioremediation of aromatic hydrocarbons in groundwater and sediments is ofen limited by the inability to provide sufficient oxygen to the contaminated zones due to the low water solubility of oxygen. Anaerobic processes refer to a variety of biodegradation mechanisms that use nitrate, ferric iron, sulfate, and carbon dioxide as terminal electron accepters. The objectives of this study was to conduct laboratory-scale microcosm studies in assessing enhanced bioremediation potential of BTEX and MTBE under various electron accepters(aerobic, nitrate, ferric iron, sulfate) in contaminated Soil. these results suggest that, presents evidence and a variety pattern of the biological removal of aromatic compounds under enhanced nitrate-, Fe(III)-, sulfate-reducing conditions.

• Microbiology and Biotechnology Letters
• /
• v.40 no.4
• /
• pp.414-418
• /
• 2012

The quantity of research on microbial fuel cells has been rapidly increasing. Microbial fuel cells are unique in their ability to utilize microorganisms and to generate electricity from sewage, pig excrement, and other wastewaters which include organic matter. This system can directly produce electrical energy without an inefficient energy conversion step. However, with MFCs maximum power production is limited by several factors such as activation losses, ohmic losses, and mass transfer losses in cathodes. Therefore, electron acceptors such as nitrate and ferric ion in the cathodes were utilized to improve the cathode reaction rate because the cathode reaction is very important for electricity production. When 100 mM nitrate as an electron acceptor was fed into cathodes, the current in single-cathode and dual-cathode MFCs was noted as $3.24{\pm}0.06$ mA and $4.41{\pm}0.08$ mA, respectively. These values were similar to when air-saturated water was fed into the cathodes. One hundred mM nitrate as an electron acceptor in the cathode compartments did not affect an increase in current generation. However, when ferric ion was used as an electron acceptor the current increased by $6.90{\pm}0.36$ mA and $6.67{\pm}0.33$ mA, in the single-cathode and dual-cathode microbial fuel cells, respectively. These values, in single-cathode and dual-cathode microbial fuel cells, represent an increase of 67.1% and 17.6%, respectively. Furthermore, when supplied with ferric ion without air, the current was higher than that of only air-saturated water. In this study, we attempted to reveal an inexpensive and readily available electron acceptor which can replace platinum in cathodes to improve current generation by increasing the cathode reaction rate.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1997.06a
• /
• pp.73-77
• /
• 1997

• Journal of Environmental Science International
• /
• v.4 no.2
• /
• pp.181-194
• /
• 1995

Flocculation kinetics using ferric nitrate as a coagulant to coagulate kaolin clay in water was examined as a tool to investigate the effect of low temperature under tightly controlled treatment conditions. Both the particle size distribution data obtained from Automatic Image Analysis (AIA) system and the on-line measurement of the degree of turbidity fluctuation in a flowing suspension by Photometric Dispersion Analyzer (PDA) were used to measure flocculation kinetics. Results show that cold water temperature had a pronounced detrimental effect on flocculation kinetics. For improving flocculation kinetics at low water temperature, maintaining constant pOH to adjust water chemistry for temperature changes was found to be partially effective only in the more acidic pH range studied.

• Microbiology and Biotechnology Letters
• /
• v.31 no.2
• /
• pp.197-200
• /
• 2003

In oil-contaminated environments, anaerobic biodegradation of toluene depended on the concentration and distribution of terminal electron acceptor as well as the physicochemical properties such as DO concentration, redox potential and pH. This study showed the anaerobic biodegradation of toluene in two different soils by using nitrate reduction, ferric iron reduction, sulfate reduction and methanogensis. Toluene degradation rates in the soil samples taken from rice filed and tidal mud flat by nitrate reduction were higher than those by other processes. Tho soil samples from the two fields were enriched for 130 days by providing toluene as a sole carbon source and nitrate or sulfate as a terminal electron acceptor. The toluene degradation rates in the enriched denitrifying consortia obtained from the rice field and tidal mud flat soil were 310.7 and 200.6 $\mu$mol$ L^{-1}$ / $d^{-1}$, respectively. The toluene (legradation rates in the enriched sulfate-reducing consortia from the fields ranged fi-om 149.1 to 86.1$\mu$mol $L^{-1}$ / $d^{-1}$ .

• Journal of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.70-81
• /
• 1989

Reverse phase liquid chromatographic elution behaviors of salicylic acid and its derivatives were studied with classical and modern high-performance liquid chromatography(HPLC) using Amberlite XAD-4 and XAD-7 resin packed columns. Capacity factors(k') were determined in the comparatively high concentration(from 0. 010F to 0. 150F) of ferric nitrate-50% methanol solution to elucidate the elution behaviors with classical method. On the other hand, k's were measured in the various concentrations of methanol and ferric nitrate(from $2.5{\times}10^{-4}F\;to\;1.0{\times}10^{-3}F$) solution of pH 2. 25 and 293K with HPLC to explain the elution mechanism of them, and to find their optimum separation condition. As a result, it was found that log k's of salicylic acid and its derivatives were decreased with increasing the concentration of ferric ion, and the decreasing slopes of the compounds on the increasing ferric ion concentrations were related with each stability constant of ferric salicylates. Some isomers of derivatives of salicylic acid could be separated in the optimum condition.

• Journal of the Korean Society of Combustion
• /
• v.8 no.2
• /
• pp.27-33
• /
• 2003

Synthesis of carbon nanomaterials on a metal substrate by an ethylene fueled inverse diffusion flame was illustrated. Stainless steel plates were used for the catalytic metal substrate. The effects of catalyst metal particles were investigated through $Fe(NO_3){_3}$ (ferric nitrate, nonahydrate) and $Ni(NO_3){_2}$ (nickel nitrate, hexahydrate). Carbon nanotubes and nanofibers with diameters of $30{\sim}70nm$ were found on the substrate for the case of using SUS304 substrates only and using them with metal nitrates. In case of using metal nitrates, due to the easy activation of the metal particles, the formation and growth of carbon nanomaterials were occurred in the lower temperature region than that of using SUS304 substrates only.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1391-1396
• /
• 2013

The photocontrolled reduction of silver nitrate to silver (Ag) nanoparticles on honeycomb-patterned poly(N-vinylcarbazole) (PVK)-cellulose triacetate (CTA) composite thin films was studied. The composites were prepared via the oxidative polymerization of N-vinylcarbazole with ferric chloride using different CTA concentrations. A honeycomb-patterned film was fabricated by casting the composite solution under humid conditions. Ag particles with a homogeneous distribution were produced by the composite film in a moderate CTA concentration, whereas aggregated Ag was obtained from the pure PVK film.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1997.10a
• /
• pp.173-179
• /
• 1997

출발원료로 ferric nitrate, ethylene glycol, acethyl acetone 혼합용액을 사용하여 dip-coating된 $\alpha$-Fe$_2$O$_3$막을 제조하였다. coating을 위한 혼합용액의 시간의 경과에 따른 용액내의 가교(polymerization) 효과를 관찰하기 위해서 적외선 분광기(FT-IR)을 사용하였고, 막 형성 시 유기물 분해 및 결정화 시작 온도를 확인하기 위하여 FT-IR, XRD, DSC 등을 이용하여 분석을 행하였다. 또한 각 조건에서 제조된 막은 X-선 회절 분석을 통해 결정상을 확인 하였으며, SEM을 통하여 막의 두께 변화에 대하여 관찰하였다.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.409-412
• /
• 2001

The high purity manganese oxides were made from the dust, generated in AOD process that produces a medium-low carbon ferromanganese and collected in the bag filter. Manganese oxide content in the dust was about 90%, and its phase was confirmed as Mn₃O₄. In the extraction of manganese, because of remaining amorphous MnO₂, the dust was reduced to MnO by roasting with charcoal. The pulp density of the reduced dust can control pH of the solution more than 4 and then Fe ion is precipitated to a ferric hydroxide. Because a ferric hydroxide co precipitates with Si ion etc, Fe, Si ion was removed f개m the solution. Heating made water to be volatized and nitrates was left in reactor Then nitrates were a liquid state and stirring was possible. Among the nitrates in reactor, only the manganese nitrate which have the lowest pyrolysis temperature pyrolyzed into β-MnO₂powder and NO₂(g) at the temperature less than 200℃. When the pyrolysis of manganese nitrate has been completed about 90%, injection of water stopped the pyrolysis. Nitrates of impurity dissolved and the spherical high purity β-MnO₂powders were obtained by filtering and washing. Mn₂O₃or Mn₃O₄ powder could be manufactured from β-MnO₂powder by controlling the heating temperature. Lastly, a manufactured manganese oxide particle has 99.97% purity.