• Clean Technology
• /
• v.22 no.4
• /
• pp.281-285
• /
• 2016

Cu wire catalyst was highly reactive toward catalytic wet peroxide oxidation of the highly refractory 1,4-dioxane. While complete removal of 1,4-dioxane could be achieved with the catalyst, the removed 1,4-dioxane could not totally mineralized into $CO_2$ and $H_2O$. In accordance with the disappearance of 1,4-dioxane, formaldehyde and oxalic acid were formed gradually with reaction time and they went through maxima. At around the time of maximum concentrations of these two intermediates acetaldehyde concentration was increased drastically and showed maximum value. With the disappearance of these three intermediates, formic acid together with ethylene glycol diformate began to increase gradually. The Cu wire catalyst was proved also to be highly stable against deactivation during the reaction.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.4
• /
• pp.393-400
• /
• 2008

1,4-Dioxane($C_4H_8O_2$), which is used as a solvent stabilizer, could make harmful effects on ecosystem because of its higher solubility, toxicity and carcinogenic by US EPA. From 2011, its discharge limit to waterbody will be regulated at 5 mg/L by Ministry of Environment Republic of Korea. It was thus to investigate that the currently operating activated sludge in polyester manufacturing processes in Gumi can properly treat it to meet with the regulation standard. For that purpose, the removal rate of 1,4-dioxane and its microbial properties were assessed for a few companies(i.e. K, H and T). Its removal efficiency was the most highly recorded in H as 98% and then 77% for K, which met with the regulation standard. However, concentration of 1,4-dioxane of T was 23 mg/L in the effluent, which is more than the regulation standard. Aside from, microbial degradation test was done for 100 ppm of 1,4-dioxane in BSM (Basal salt medium) inoculated with each of activated sludge. After 7 days, 1,4-dioxane was completely removed in the test bottle inoculated with H sludge, 67% in T and 52% in K, which could confirm that the given activated sludge might have different biodegradability against the amount of 1,4-dioxane. Therefore, microbial diversity in each company was investigated by 16s rDNA cloning methods where a species, e.g. Methylibium petroleiphilum PM1, was the greatest observed from H and in lesser from K, but it was not detected from T. Methylibium petroleiphilum PM1 is known to efficiently degrade ether like methyl tertiary-butyl ether(MTBE). It is concluded that the activated sludge in H can be most effectively adopted for a biodegradation of 1,4-dioxane in the concern of industrial sector.

• Applied Chemistry for Engineering
• /
• v.30 no.4
• /
• pp.466-471
• /
• 2019

1,4-dioxane and dichloromethane are classified as carcinogenic groups in the International Agency for Research on Cancer (IARC). They are frequently released at high concentrations in an industrial wastewater effluent. The acute toxicity (24 h) of Daphnia magna for 7.53 mg/L of 1,4-dioxane in the industrial effluent was evaluated as 1.1 TU (toxic unit) and showed TU close to the effluent quality standard. Mixed substances of 1,4-dioxane and dichloromethane in the industrial effluent showed relatively high TU as compared to that of a single substance. Half maximal effective concentration (24 h $EC_{50}$) values of 1,4-dioxane and dichloromethane for the synthetic wastewater prepared in laboratory were 1,744 (0.06 TU) and 170 mg/L (0.6 TU), respectively and the toxicity was low. Nevertheless the toxicological evaluation of the mixture showed that TU values increased to 0.02, 0.04 and 0.10, respectively as 1, 5 and 10 ppm of dichloromethane was added to 100 ppm of 1,4-dioxane. And the synergistic effect was observed between two substances. But the TU value of synthetic wastewater was below 5%, lower than that of industrial effluent at the similar concentration.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.6
• /
• pp.436-441
• /
• 2013

An experiment using a 5 m-long sand column was performed to evaluate the resisting capability against micro-pollutants of the infiltration gallery, multi-purpose filtration pond and riverbank/bed filtration, of which the filtration distance is becoming increasingly shorter in Korea. Results suggested that the Korean riverbed sand contained significant amount of organics, resulting in a relatively vigorous adsorption of chloride ion on the sand surface. Results also indicated that while phenol was not detected in the column filtrate, both 1,4-dioxane and diazinon were exposed to adsorption by the sand as they moved through the column, decreasing their peak concentrations during the movement. It can be expected that the peak concentrations will diminish significantly in the practical scale due to its longer travel distance.

• Analytical Science and Technology
• /
• v.18 no.3
• /
• pp.173-187
• /
• 2005

• Journal of the Korean Chemical Society
• /
• v.31 no.6
• /
• pp.503-508
• /
• 1987

The protonation constants of 3,4 : 9,10-dibenzo-1,12-diaza-5,8-dioxacyclotetradecane $(NenOenH_4)$ and stability constants of its transition metal complexes have been determined by the potentiometric titration in 1 : 1 dioxane-water mixture with 0.1 ionic strength at $25^{\circ}C.$ For a given anion system, the stabilitv constants of the complexes are in the order of $Mn^{2+}<\;Co^{2+}\;< Ni^{2+}\;<\;Cu^{2+}\;>\;Zn^{2+}$, which accords with the Williams-Irving series.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.368-368
• /
• 2019

경제의 발전과 더불어 사회가 복잡해지면서 재난의 발생은 다양한 형태로 더욱 복잡하게 발생하고 있다. 최근들어 매년 발생하는 가뭄과 기후적 특성으로 인한 유량의 변동성으로 인해 수질오염이 심해지기를 반복하고 있다. 특히, 산업단지나 화재 등 여러 가지 원인으로 인해 수질오염사고도 빈번하게 발생하고 있으며 심한 경우 취수원의 취수중단과 같은 심각한 상황을 발생하기도 한다. 최근들어 심각한 가뭄과 폭염으로 인해 취수원의 수질이 악화되는 사고들이 발생하고 있으며, 과거 수질오염사고를 살펴보면 1991년에 낙동강에서 발생한 구미 두산전자의 페놀방류에 의한 사고로 18시간 동안 대구에 취수가 중단된 적이 있으며, 1994년 대구광역시 성서공단에서 배출된 유기용제에 의해 낙동강 수계 5개 정수장이 취수가 중단된 바도 있다. 또한 2008년 김천공단 (주)코오롱 유화에서 방류된 페놀에 의해 대구의 취수원 중 두류, 매곡취수장이 5시간동안 취수가 중단된바 있으며, 2009년 다이옥산 배출, 2015년 구미공단에서 불소, 암모니아성 질소, 1.4 다이옥산 배출사고, 2018년 과불화화합물에 낙동강 수질사고, 운문댐과 가창댐 유역의 가뭄으로 인한 취수정지 상태가 발생하는 등 대구광역시 시민들의 먹는 물에 대한 불안이 끊이지 않고 있다(Peacenews, 2018). 본 연구는 대구광역시의 상수도시설이 재난상황 발생에 따라 취수가 중단되어 물을 생산하는 취수장이 불능상태가 되는 가상의 시나리오를 설정하고 각 정수장에서 용수를 공급할 수 있는 대응에 대해서 검토하였다. 대구시에서 운영하는 정수장은 총 5개이며, 전체 공급량의 60.5%를 낙동강을 수원으로 하는 매곡과 문산정수장에서 취수하고 있다. 가상의 재난상황 시나리오는 각각의 정수장이 재난발생에 따라 운영이 불가능한 경우인 Scenario 1(a)~(e)와 매곡과 문산정수장이 운영불가능한 경우인 Scenario 2를 가정하여 용수공급 대응방안에 대해 검토하였다. 그 결과 Scenario 1(a)~(e)에서는 매곡정수장이 운영이 불가능한 경우 대구광역시 전체의 용수공급 신뢰도 80.4%로 250 lpcd를 공급할 수 있으며, Scenario 2의 경우에는 낙동강 오염사고로 인해 매곡과 문산정수장이 운영이 불가능할 경우 60.4%의 신뢰도로 205 lpcd를 공급할 수 있는 것으로 검토되었다.

• Polymer(Korea)
• /
• v.31 no.2
• /
• pp.98-104
• /
• 2007

The expansion behavior of polystyrene (PS) chains with various molecular weights has been investigated above Flory $\Theta$temperature by viscometry after dissolving in the three different mixed solvents systems such as benzene/n-heptane, 1,4-dioxane/isopropanol, and 1,4-dioxane/n-heptane. Two different regimes are observed as increasing temperature: one regime is for the expansion of chain and the other is for the contraction. For the higher molecular weight sample of PS, the higher peak temperature showing its maximum expansion is obtained. Within a certain system of Ps/mixed solvents, the $\tau/\tau_c$ parameter shows universality for the variation of molecular weight. But while each system of Ps/mixed solvents has shown its own different slope, the universality breaks down in the overall system of mixed solvents. However after introducing a new empirical $b^{2/3}\tau/\tau_c$ parameter, all data points of three different systems have dropt on one master curve and the universality of chain expansion has recovered again. Here $\tau$ and $\tau_c$ are defined as $(T-\Theta)/\Theta$ and $(\Theta-T_c)/T_c$, respectively and $T_c$ is the critical solution temperature, and b of Schultz-Flory equation is corresponding to the effective slope in the plot of $1/T_c$ against $1/M_w^{1/2}$.

• Journal of the Korean Applied Science and Technology
• /
• v.25 no.1
• /
• pp.32-40
• /
• 2008

1,4-Dioxane is an EPA priority pollutant often found in contaminated ground waters and industrial effluents. Conventional water treatment techniques are limited to decompose this compound effectively. Therefore, an advanced oxidation process system (AOP) was used for the degradation of 1,4-dioxane. This research investigates the effect of adding oxidants, such as ozone, air, and $H_2O_2$ during the UV irradiation of 1,4-dioxane solution. In order to analyze 1,4-dioxane, a modified 8270 method, which is an improved method of U.S EPA 8720, was used. Degradation efficiencies of 1,4-dioxane by only UV irradiation at various temperatures were not significant. However, The addition of oxidants and air bubbling in the UV irradiation system for 1,4-dioxane decomposition showed the higher 1,4-dioxane degradation rate. And, during AOP treatment the tendency of TOC changes was similar to that of 1,4-dioxane decomposition rate.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.4
• /
• pp.375-383
• /
• 2007

Treatment efficiency research was performed using Fenton process and the electrochemical process in the presence of ferrous ion and hydrogen peroxide for the industrial wastewater including 1,4-Dioxane produced during polymerization of polyester. The Fenton process and the electrochemical Iron Redox Reaction (IRR) process were applied for this research to use hydroxyl radical as the powerful oxidant which is continuously produced during the redox reaction with iron ion and hydrogen peroxide. The results of $COD_{Cr}$ and the concentration of 1,4-Dioxane were compared with time interval during the both processes. The rapid removal efficiency was obtained for Fenton process whereas the slow removal efficiency was occurred for the electrochemical IRR process. The removal efficiency of $COD_{Cr}$ for 310 minutes was 84% in the electrochemical IRR process with 1,000 mg/L of iron ion concentration, whereas it was 91% with 2,000 mg/L of iron ion concentration. The lap time to remove all of 1,4-Dioxane, 330 mg/L in the wastewater took 150 minutes with 1,000 mg/L of iron ion concentration, however it took 120 minutes with 2,000 mg/L of iron ion concentration in the electrochemical IRR process.