• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.102-105
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• 1992

Introduction : Isothiazolinone product is one of new preservatives used in cooling tower, paper mill, and general industrial waters.l) It is also effective in controlling bacteria and fungi in the manufacture and storage of dispersed pigments, such as kaolin clays, titanium dioxide, calcium carbonate and others\ulcorner Its broad-spectrum activity, excellent physical and chemical compatibility with anionic, nonionic and cationic surfactants and most organic and inorganic compounds and low toxicity at recommended use levels provide formulators with an effective, economical, and environmentally acceptable alternative to other commercial biocides. It dose not contain or generate formaldehyde and is easy to formulate (1.5% solution is supplied as an aqueous solution), so that it gains advantage over the other preservatives. The active ingredients of the isothiazolinone product are unchlorinated compound (2-methyl-4-isothiazolin-3-one) and chlorinated one (5-chloro-2-methyl-4-isothiazolin-3-one). Methods preferred for the analysis of preservatives are chromatographic methods, especially high performance liquid chromatograph (HPLC). Although several methods were satisfactory in respect to separation, no offical method has been published for the isothiazolinone components. This study was performed to search for an alternative method in order to show flexible operating conditions of HPLC and to reduce assay time.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.58-61
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• 2002

An alternative to pump and treat groundwater remediation is the use of reactive barriers. Zero valent iron (ZVI) is particularly useful as a reductant of chlorinated hydrocarbons because of its low cost and lack of toxicity ZVI can drive the dechlorination of chlorinated organic compounds and the reduction of chromium from the Cr(Ⅵ) to the Cr(III) state. The contaminants in subsurface environment usually exist as the mixed compounds. Therefore, the objective of this research is to study the effect of the other compounds on TCE removal by ZVI. The removal mechanism of TCE by ZVI is separated the dechlorination and sorption. TCE removal by ZVI slightly increased in presence of naphthalene as the non-reduced compound. TCE removal by ZVI remarkable decreased in presence of carbon tetrachloride, nitrate, and chromate as the reduced compounds. This research suggests that the effect of the coexisted compounds on the removal chlorinated compounds by reactive barrier technology should be considered for practical application.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.33-36
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• 2006

The reductive dechlorination of chlorinated organic compounds by soil minerals in soil and groundwater were carried out in this study. FeS, green rust, and magnetite were chosen as the representative soil minerals which were capable of degrading chlorinated compound in soil system. FeS was the most effective reductant in degradation of carbon tetrachloride. The reductive degradation of CT and 1,1,1-TCA by FeS was much faster than that of 1,2-DCB and 2,4-DCP. The reactivity of FeS was effectively improved by the addition of trace metals. The addition of Co to FeS suspension enhanced the reaction rate of 1,2-DCB by a factor of 46 compared to that by FeS without Co.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1148-1152
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• 2008

Molten carbonate oxidation (MCO) is one of the promising alternative technologies for the treatment of the chlorinated organic compounds because it is capable of trapping chlorine during a destruction of them. In this study, destructions of chlorinated organic compounds ($C_6H_5Cl$, $C_2HCl_3$ and $CCl_4$) and an insulated oil containing PCBs were performed by using the two stage molten carbonate oxidation system. MCO reactor temperature largely affected the destruction of the chlorinated organic compounds. Destruction of the chlorinated organics very efficient in the primary MCO reactor however a significant amount of CO was emitted from the MCO system. This CO emission was gradually decreased by an increase in the primary reactor temperature and oxidizing air feed rate. The HCl emission from the MCO system was below 7 ppm regardless of tested conditions. The chlorine collection efficiencies were in the range of 99.95-99.99%. The destruction of PCBs in the insulated oil was efficient at a temperature above $900^{\circ}C$ and overall destruction efficiency of them was determined as over 99.9999%.

• Environmental Engineering Research
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• v.17 no.2
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• pp.103-110
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• 2012

This study was performed mainly to examine whether a city with a metal industrial presence presents different characteristics in ambient volatile organic compound (VOC) concentrations compared to residential (RES) and commercial/residential combined (CRC) areas of another city by using long-term monitoring data (from January 2006 to February 2009). For most target VOCs, ambient concentrations in the metal-industrialized city were lower than for the RES and CRC areas. Aromatic compounds were the predominant VOC groups for the metal industry city as well as for other land uses. The ambient concentrations of aromatic VOCs were higher in the winter and spring seasons than in the summer and fall seasons, whereas those of chlorinated VOCs did not show any distinctive variations. In addition, higher concentrations were observed during daytime hours. The correlations between the ambient target compounds were statistically significant, except for the correlation between benzene and ozone.

• Clean Technology
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• v.7 no.3
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• pp.195-202
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• 2001

In this study the trace of chlorinated organic compound in aqueous solution was separated by pervaporation process using crosslinked PDMS (polydimethylsiloxane) membrane. The flux of trichloroethylene(TCE) increased linearly with feed composition but the flux of water was slightly increased. The partial flux of TCE was greater than that of tetrachloroethylene(PCE). The partial flux of TCE was not changed with operating temperature, but increased rapidly with feed flow rates. High crosslinking density causes the reduction of solubility and diffusivity for target component. The reduction of flux and selectivity for TCE is due to the chain immobilization and reduction of diffusivity with crosslinking density.

• Journal of the Korean Chemical Society
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• v.11 no.2
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• pp.45-50
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• 1967

Radio thin layer chromatography of organic halogen compounds by neutron irradiation technique was investigated for the purpose of identifying and separating the mixture of halogen compounds. It was found that various halides, organic acids, and aldehyde gave a distinct developing peak both in cases of individual compound and a mixture of two or three components when the samples were developed by solvent methanol. But poly chlorinated compounds and aromatic or alicyclic chlorides gave more than one component peak when the sample was developed after neutron irradiation. Rf value of each compound was distinct and reproducible. The procedures were described and validity of the present method is discussed.

• Membrane Journal
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• v.4 no.1
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• pp.57-62
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• 1994

This study uses pervaporation process to separate small amount of organic trichloroethylene, chloroform and perchloroethylene from contaminated water, since chlorinated hydrocarbones are known to be cancer suspecting compounds. For the separation of small amount of halogenated organic compound dissolved in wastewater, pervaporation membranes should be polymers that possess affinity with orgnic compounds and hydrophobicity. We used polyisobutylene, polyetheramide and polydimethylsiloxane membranes. The degree of affinity between organics and polymers were measured by contact angle method. We had good separation results that separation factor ranged from 34 to 19100 and permeate flux was$19.7~140g/m^2hr$.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.69-77
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• 2020

Oxidative degradation of phenol, three monochlorophenols (2-chlorophenol, 2-CP; 3-chlorophenol, 3-CP; 4-chlorophenol, 4-CP), four dichlorophenols (2,3-dichlorophenol, 2,3-DCP; 2,4-dichlorophenol, 2,4-DCP; 2,5-dichlorophenol, 2,5-DCP; 2,6-dichlorophenol, 2,6-DCP), and two trichlorophenols (2,4,5-trichlorophenol, 2,4,5-TCP; 2,4,6-trichlorophenol, 2,4,6-TCP) was conducted with heat activated persulfate. As the number of chlorinations increased, the reaction rate also increased. The reaction rate was relatively well fitted to the zero-order kinetic model, rather than the pseudo-first order kinetic model for the reactions at 60 ℃, which can be explained by insufficient activation of the persulfate at 60 ℃, and the oxidation reaction of 2,4,6-TCP at 70 ℃ was relatively well fitted to the pseudo-first order kinetic model. The oxidation reaction rate generally increased with increase of persulfate concentration in the solution. 2,6-dichloro-2,5-cyclohexadiene-1,4-dione was found as a degradation product in a GC/MS analysis. This compound is a non-aromatic compound, and one chlorine was removed. This result is similar to the result of previous studies. The current study proved that heat activated persulfate activation could be an alternative remediation technology for phenol and chlorophenols in soil and groundwater.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.105-114
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• 2007

The most advanced oxidation processes (AOPs) are based on reactivity of strong and non-selective oxidants such as hydroxyl radical (${\cdot}OH$). Decomposition of typical DNAPL chlorinated compounds (TCE, PCE) using various advanced oxidation processes ($UV/Fe^{3+}$-chelating agent/$H_2O_2$ process, $UV/H_2O_2$ process) was approached to develop appropriate methods treating chlorinated compound (TCE, PCE) for further field application. $UV/H_2O_2$ oxidation system was most efficient for degrading TCE and PCE at neutral pH and the system could remove 99.92% of TCE after 150 min reaction time at pH 6($[H_2O_2]$ = 147 mM, UVdose = 17.4 kwh/L) and degrade 99.99% of PCE within 120 min ($[H_2O_2]$ = 29.4 mM, UVdose = 52.2 kwh/L). Whereas, $UV/Fe^{3+}$-chelating agent/$H_2O_2$ system removed TCE and PCE ca. > 90% (UVdose = 34.8 kwh/L, $[Fe^{3+}]$ = 0.1 mM, [Oxalate] = 0.6 mM, $[H_2O_2]$ = 147 mM) and 98% after 6hrs (UVdose = 17.4 kwh/L, $[Fe^{3+}]$ = 0.1 mM, [Oxalate] = 0.6 mM, $[H_2O_2]$ = 29.4 mM), respectively. We improved the reproduction system with addition of UV light to modified Fenton reaction by increasing reduction rate of $Fe^{3+}$ to $Fe^{2+}$. We expect that the system save the treatment time and improve the removal efficiencies. Moreover, we expect the activity of low molecular organic compounds such as acetate or oxalate be effective for maintaining pH condition as neutral. This oxidation system could be an economical, environmental friendly, and practical treatment process since the organic compounds and iron minerals exist in nature soil conditions.