• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.4
• /
• pp.293-302
• /
• 1998

This study was performed to investigate the behavior of chlorobenzenes (CIBZS) and chlorophenols (CIPhs) in a thermally treated MSWI fly ash. The experiment was carried out in a fixed bed reactor at the temperature range of 300~$600^{\circ}C$. Reaction time range was between 30 and 120 minutes, and NB and 02 gases were used as carrier gas. The decomposition rate of CIBZS was more affected by reaction time than by the reaction temperature. The decomposition rate of CIPhs was affected by both parameters. Decomposition rate of CIBZS and CIPhs reached 80.4% and 96.6% at $600^{\circ}C$, 120 min, respectively. Considering the effect of O2 content, decomposition rate of CIBZS and CIPhs was the highest at 10% of O2 content. Declorination and decomposition reactions Pere investigated by analyzing homologue distribution. Higher chlorinated CIBZS and CIPhs homologue decreased but lower chlorinated compounds increased with the increase of temperature. Effect of O2 on the homologue distribution of these compounds was not clear in the range of our experiment conditions.

• Environmental Engineering Research
• /
• v.10 no.4
• /
• pp.165-173
• /
• 2005

Nano-sized iron particles were synthesized by reduction of $Fe^{3+}$ in aqueous solution under two reaction conditions, aerobic and anaerobic, and the reactivity of iron was tested by reaction with trichloroethene (TCE) using a batch system. Results showed that iron produced under anoxic condition for both synthesis and drying steps gave rise to iron with higher reduction reactivity, indicating the presence of oxygen is not favorable for production of nano-sized iron deemed to accomplish reactivity enhancement from particle sized reduction. Nano-sized iron sample obtained from the anoxic synthesis condition was further characterized using various instrumental measurements to identity particle morphology, composition, surface area, and particle size distribution. The scanning electron microscopic (SEM) image showed that synthesized particles were uniform, spherical particles (< 100 nm), and aggregated into various chain structures. The effects of other synthesis conditions such as solution pH, initial $Fe^{3+}$ concentration, and reductant injection rate on the reactivity of nano-sized iron, along with standardization of the synthesis protocol, are presented in the companion paper.

• Applied Biological Chemistry
• /
• v.21 no.1
• /
• pp.1-10
• /
• 1978

In an effort to elucidate degradation mechanisms of an acetanilide herbicide, Butachlor, by soil microorganisms, a common soil fungus, Chaetomium globosum which is known to be powerful was selected and incubated in a Butachlor-contained medium. The results obtained from the resulting metabolites are as follows: (1) Dechlorination from Butachlor occurred very easily, remaining almost constant after 180 hrs. of incubation. (2) More than 10 metabolites were isolated and characterized, of which the metabolites, m/e 205, 177, 223, 182, and 206 were the main products. (3) In this paper, the structures and pathways of formation of metabolites, m/e 206, 182, 223, 225, and 189 were tentatively proposed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.68-71
• /
• 2004

Effects of surfactants and natural organic matter (NOM) on the sorption and reduction of tetrachloroethylene (PCE) and chromate with iron were examined in this study. PCE and chromate reduction by iron depended on the ionic type of the surfactants in this study. The apparent reaction rate constants of PCE with Triton X-100 and hexadecyltrimethyl ammonium (HDTMA) at one half and two times of the critical micelle concentration (CMC) were relatively higher than without surfactants because of the enhanced PCE partitioning and surface concentration. In the presence of sodium dodecyl benzene sulfonate (SDDBS) at 2000 mg/L and NOM at 50 mg/L, the apparent reaction rate constants of PCE increased, but TCE production decreased. The enhanced removal rate of PCE was not due to the dechlorination, and the sorption was dominant iron with SDDBS and NOM. The apparent reaction rate constants of chromate by iron with Triton X-100 and NOM were 1.4-3.1 times lower than without surfactants while that with HDTMA was two times higher than without HDTMA, When the sorbed HDTMA molecules form admicelles, negatively-charged chromate has an affinity for the positively-charged HDTMA head group.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 1991.05a
• /
• pp.8-12
• /
• 1991

Biodegradation of carbon tetrachloride (CTC) in denitrifying and aerobic columns was investigated under various conditions of electron-acceptor and electron-donor availability. CTC removal increased when the electron-acceptor (nitrate) injection was stopped in the denitrifying column ; however, CTC removal decreased when electron donor (acetate) was deleted in the denitrifying and the aerobic column. Small fractions of the CTC removed appeared as chloroform, indicating that reductive dechlorination of CTC was occurring. The results from the denitrifying column support the hypothesis that CTC behave as an electron acceptor that competes for the pool of available electrons inside the bacterial cells.

• Textile Coloration and Finishing
• /
• v.3 no.1
• /
• pp.37-45
• /
• 1991

면직물의 Embossing 가공은 의류, 종이, 가죽 제품 등에 수요가 상당히 많고, Moire 및 Schreiner 가공은 의류에 이용되고 있다. 原布(grey)$\rightarrow$(2) 檢布(cloth inspection).標識(marking)$\rightarrow$((3) 節取(knotting), 修正(mending), 汚染빼기(stain removing)$\rightarrow$((4) 필이음(cloth sewing).rolling$\rightarrow$((5) 燒毛(singeing)v(6) 糊拔(desizing)$\rightarrow$((7) 水洗(washing)$\rightarrow$((8) 精練(scouring)$\rightarrow$((9) 水洗(washing)$\rightarrow$((10) 漂白(bleaching)$\rightarrow$((11) 水洗(washing)$\rightarrow$((12) 酸處理(souring)$\rightarrow$((13) 水洗(washing)$\rightarrow$((14) 打布(scutching)$\rightarrow$((15) 脫鹽素處理(dechlorination).水洗 (16) 螢光漂白(optical bleaching). 乾燥(drying)$\rightarrow$((17) Mercerizing.水洗.乾燥$\rightarrow$((18) 染色(dyeing).捺染(printing).水洗.乾燥$\rightarrow$((19) 樹脂液 padding 및 豫備乾燥$\rightarrow$((20) Embossing calendering(또는 moire calendering, schreiner miendering)$\rightarrow$((21) 熱處理(curing)$\rightarrow$((22) Soaping$\rightarrow$((23) 乾燥$\rightarrow$((24) 給混 (damping)$\rightarrow$((25) 幅내기$\rightarrow$((26) 最終檢布(final inspection)$\rightarrow$((27) 천접기(holding) $\rightarrow$((28) 整布(1필씩 짜르기)$\rightarrow$((29) 천감기(1필씩 또는 1권으로)$\rightarrow$((30) 商標붙이기(marking).包裝(packing).荷造(baling).出荷(forward)

• Journal of Microbiology
• /
• v.42 no.3
• /
• pp.188-193
• /
• 2004

Xanthobacter flavus strain UE15 was isolated in wastewater obtained from the Ulsan industrial complex, Korea. This strain functions as a 1,2-dichloroethane (1,2-DCA) degrader, via a mechanism of hydrolytic dechlorination, under aerobic conditions. The UE15 strain was also capable of dechlorinating other chloroaliphatics such as 2-chloroacetic acid and 2-chloropropionic acid. The dhlA gene encoding 1,2-DCA dechlorinase was cloned from the genomic DNA of the UE15 strain, and its nucleotide sequence was determined to consist of 933 base pairs. The deduced amino acid sequence of the DhlA dechlorinase exhibited 100％ homology with the corresponding enzyme from X. autotrophicus GJ10, but only 27 to 29％ homology with the corresponding enzymes from Rhodococcus rhodochrous, Pseudomonas pavonaceae, and Mycobacterium sp. strain GP1, which all dechlorinate haloalkane compounds. The UE15 strain has an ORF1 (1,356 bp) downstream from the dhlA gene. The OFR1 shows 99％ amino acid sequence homology with the transposase reported from X. autotrophicus GJ10. The transposase gene was not found in the vicinity of the dhlA in the GJ10 strain, but rather beside the dhlB gene coding for haloacid dechlorinase. The dhlA and dhlB genes were confirmed to be located at separate chromosomal loci in the Xanthobacter flavus UE15 strain as well as in X. autotrophicus GJ10. The dhlA and transposase the UE15 strain were found to be parenthesized by a pair of insertion sequences, 181247, which were also found on both sides of the transposase gene in the GJ10 strain. This unique structure of the dhlA gene organization in X. flavus strain UE15 suggested that the dechlorinase gene, dhlA, is transferred with the help of the transposase gene.

• Journal of the Mineralogical Society of Korea
• /
• v.16 no.1
• /
• pp.107-123
• /
• 2003

The objective of this study was to investigate mineral precipitates, which derived from the zero valent iron (ZVI) corrosion during TCE dechlorination and to find the controlling factors in mineral precipitates. A series of column experiemnts were conducted to evaluate the location of ZVI and the effects of electrode arrangements in electro-enhanced permeable reactive barrier (E2PRB) systems. Based on mineralogical study, ZVI samples near the influent port had more lepidocrocite, ferrihydrite or Fe (oxy)hydroxide, and (phospho)siderite while backward samples had more akaganeite, magnetite/maghemite, and intermediate green rust (GR) I and GR II. A suite of mineral distribution was preferabley related to the dissolved oxygen and the increased pH. Controlling factors of mineral precipitates in an E2PRB system were found to be (1) pH, (2) dissolved oxygen, (3) the types of Fe intermediates, and (4) anionic species to form complex strongly.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.3
• /
• pp.366-372
• /
• 2003

The production of microbiologically enriched cultures that degrade cis- 1,2-dichloroethylene(DCE) under anaerobic conditions was investigated. Among 80 environmental samples, 19 displayed significant degradation of $10{\mu}M$ cis-DCE during 1 month of anaerobic incubation, and one sediment sample collected at a landfill area (Nanji-do, Seoul, Korea) showed the greatest degradation ($94\%$). When this sediment culture was subcultured repeatedly, the ability to degrade cis-DCE gradually decreased. However, under Fe(III)-reducing conditions, cis-DCE degradation by the subculture was found to be maintained effectively. In the Fe(III)-reducing subculture, vinyl chloride (VC) was also degraded at the same extent as cis-DCE No accumulation of VC during the cis-DCE degradation was observed. Thus, Fe(III)-reducing microbes might be involved in the anaerobic degradation of the chlorinated ethenes. However, the subcultures established with Fe(III) could function even in the absence of Fe(III), showing that the degradation of cis-DCE and VC was not directly coupled with the Fe(III) reduction. Consequently, the two series of enrichment cultures could not be obtained that degrade both cis-DCE and VC in the presence or absence of Fe(III). Considering the lack of VC accumulation, both cultures reported herein may involve interesting mechanism(s) for the microbial remediation of environments contaminated with chlorinated ethenes. A number of fermentative reducers (microbes) which are known to reduce Fe(III) during their anaerobic growth are potential candidates involved in cir-DCE degradation in the presence and absence of Fe(III).

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.1
• /
• pp.40-46
• /
• 2005

Clostridium bifermentans strain DPH-1 has already been found to dechlorinate perchloroethylene (PCE) to cis-dichloroethylene (cis-DCE) via trichloroethylene (TCE). In this study, our investigation on different culture conditions of this DPH-1 strain was extended to find a more efficient and cost effective growth medium composition for this DPH-1 strain in bioremediation practices. Temperature dependency of strain DPH-1 showed that the growth starting time and PCE degradation at $15^{\circ}C$ was very slow compared to that of $30^{\circ}C$, but complete PCE degradation occurred in both cases. For the proper utilization of strain DPH-1 in more cost effective bioremediation practices, a simpler composition of an effective media was studied. One component of the culture medium, yeast extract, had been substituted by molasses, which served as a good source of electron donor. The DPH-1 strain in the medium containing molasses, in the presence of $K_{2}HPO_4\;and\;KH_{2}PO_4$, showed identical bacterial multiplication (0.135 mg protein $mL^{-1}h^{-1}$) and PCE degradation rates ($0.38\;{\mu}M/h$) to those of the yeast extract containing medium.