• 청정기술
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• 제12권3호
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• pp.145-150
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• 2006

수용액을 전기분해하면 반응성 유기화합물을 가수분해할 수 있는 수산화이온 및 수소이온을 얻을 뿐만 아니라 차아염소산이온과 같이 화합물을 산화시킬 수 있는 산화제도 얻을 수 있다. 자체 제작한 장치를 이용하여 염료 전기분해를 시도하였고, HPLC 및 UV-VIS 분광광도계를 이용하여 분해정도를 분석하였다. 전기분해장치를 이용하면 높은 반응속도와 저렴한 유지비용으로 염료 분해가 가능하며, 반응도중 소모되는 시약 보충 및 반응 후 부산물 처리 등의 과정이 수월하다. 다양한 염료에 대하여 분해시간을 비교하였고, 수처리 분야 응용에 대하여 토의하였다.

• 공업화학
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• 제19권6호
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• pp.674-679
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• 2008

수처리에 있어서 분말 $TiO_2$ 광촉매가 안고 있는 문제점을 극복하기 위하여 스테인리스 강 섬유를 지지체로 한 $TiO_2$ 담지 광촉매($TiO_2/SSF$)를 제조하였다. 초음파 세척기를 이용하여 담지된 $TiO_2$의 부착강도를 살펴보았으며, 메틸렌블루와 포름산 분해실험을 통하여 광촉매 활성을 평가하였고, 대장균과 비브리오균에 대한 살균실험을 통하여 살균능력을 평가하였다. 담지된 $TiO_2$는 30 min간의 초음파 처리 후에도 95% 이상이 남아 있을 정도로 강한 부착력을 보였으며, UV 하에서 60%의 메틸렌블루와 38%의 포름산을 1 h 만에 각각 분해시키는 광촉매 활성을 보였고, 대장균과 비브리오균에 대하여 99.9% 이상의 높은 살균능력을 보였다. 포름산 분해의 경우에는 산화제를 첨가하면 분해율이 증가하였으며, 특히 과산화수소를 첨가할 경우에는 분해율이 1 h 만에 80%로 증가하였다.

• 청정기술
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• 제14권3호
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• pp.218-223
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• 2008

마이크로 에멀젼 수용액에 분산된 반응성 유기화합물을 전기분해를 통하여 얻을 수 있는 수산화이온 및 수소이온을 이용하여 가수분해시키고, 분해속도를 비교하는 실험을 수행하였다. 반응물질로 사용된 p-nitrophenylacetate (PNPA)의 가수분해로부터 발생하는 p-nitrophenoxide 농도 변화에 따른 흡광도 변화를 이용하여 분해속도를 얻을 수 있었다. 자체 조립한 전기분해 장치를 이용하여 전압, 반응온도, 반응물질 양에 따른 분해속도 변화를 관찰하였다. 마이크로 에멀젼 사용으로 인하여 반응물질 용해도를 증가시킬 수 있으며, 전기분해법 사용으로 인하여 반응속도 조절이 용이하며, 유지비용이 저렴하고, 기존 화학물질 투여방법에 비해 소모되는 시약 보충 및 반응 후 부산물 처리 등의 과정이 수월하다. 유기물질 분해에 대한 메커니즘 및 수처리 분야 응용에 대하여 토의하였다.

• 한국수소및신에너지학회논문집
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• 제19권3호
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• pp.199-208
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• 2008

HI decomposition was conducted using Pt/C-based catalysts with a fixed-bed reactor in the range of 573 K to 773 K. To examine the change of the characteristic properties of the catalysts, $N_2$ adsorption analyser, a X-ray diffractometer(XRD), and a scanning electron microscopy(SEM) were used before and after the HI decomposition reaction. the effect of Pt loading on HI decomposition was investigated by $CO_2$-TPD. HI conversion of all catalysts increased as decomposition temperature increased. The XRD analysis showed that the sizes of platinum particle became larger and agglomerated into a lump during the reaction. From $CO_2$-TPD, it can be concluded that the cause for the increase in catalytic activity may be attributed to the basic sites of catalyst surface. The results of both b desorption and gasification reaction showed the restriction on the use of Pt/C-based catalyst.

• 한국산업보건학회지
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• 제22권1호
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• pp.52-59
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• 2012

Objectives: The purpose of this study was to evaluate the exposure possibility of by-products during the semiconductor manufacturing processes. Methods: The authors investigated types of chemicals generated during semiconductor manufacturing processes by the qualitative experiment on generation of by-products at the laboratory and a literature survey. Results: By-products due to decomposition of photoresist by UV-light during the photo-lithography process, ionization of arsine during the ion implant process, and inter-reactions of chemicals used at diffusion and deposition processes can be generated in wafer fabrication line. Volatile organic compounds (VOCs) such as benzene and formaldehyde can be generated during the mold process due to decomposition of epoxy molding compound and mold cleaner in semiconductor chip assembly line. Conclusions: Various types of by-products can be generated during the semiconductor manufacturing processes. Therefore, by-products carcinogen such as benzene, formaldehyde, and arsenic as well as chemical substances used during the semiconductor manufacturing processes should be controlled carefully.

• 한국안전학회지
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• 제12권2호
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• pp.87-94
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• 1997

If sodium azide is impinged by certain reasons, it will be produced explosives by heavy metals and toxic materials. But it is used propellent for inflating automotive safety bags and the other chemical manufacturing purpose. The investigation of thermal hazard potential of sodium azide itself and with polymers ate very important because some parts of automotives, transporting vessels of reactive chemicals and many any other constituents of structures in factories are made of polymers. The range of decomposition temperatures are about $360-380^{\circ}C$, even if it depends on heating rate and sample weight. Thermal decomposition heat of sodium azide in air is higher than in nitrogen atmosphere, because the former is included oxidizing heats of sodium metal which is made by decomposition of sodium azide to end. Especially decomposition temperature of polymers are increased on the order of bonding energy between atoms in hydrocarbon moleculars.

• 한국안전학회지
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• 제13권4호
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• pp.180-185
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• 1998

The evaluation of thermal and pressure hazard of chemicals on the manufacturing, transporting and storaging is important in the chemical industry for safety. In this study, the thermal decomposition characteristics of intermediate of Saccharin were investigated by using Accelerating Rate Calorimeter(ARC) and Differential Scanning Calorimeter(DSC). Experimental results showed that decomposition temperatures in p-TSA were about 280~$318^{\circ}C$ by DSC and $201^{\circ}C$ by ARC. In case of o-TSA were about $336^{\circ}C$~$360.8^{\circ}C$ by DSC and $299^{\circ}C$ by ARC. The decomposition temperature acquired by ARC was about $70^{\circ}C$ lower than that by DSC. The exothermic runaway reaction in case of p-TSA occured in 598 minute and o-TSA in 5 minute. For the safety in the chemical industry, we should consider the ARC data as well as DSC data in the handling and design of process.

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.395-402
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• 2006

Iodine-sulfur(IS) hydrogenation production process consists of three sections, which are so called a Bunsen reaction section, a HI decomposition section and a $H_2SO_4$ decomposition section as a closed cycle. For highly efficient operation of a Bunsen reaction section, we investigated the phase separation characteristics of $H_2SO_4-HI-H_2O-I_2$ system into two liquid phases($H_2SO_4$-rich phase and $HI_x$-rich phase) in the high temperature ranges, mainly from 353 to 393 K, and in the $H_2SO_4/HI/H_2O/I_2$ molar ratio of $1/2/14{\sim}30/0.3{\sim}13.50$. The desired results for the minimization of impurities in each phase were obtained in conditions with the higher temperature and the higher $I_2$ molar composition. On the basis of the distribution of $H_2O$ to each phase, it is appeared that the affinity between $HI_x$ and $H_2O$ was more superior to that between $H_2SO_4$ and $H_2O$.

• Nuclear Engineering and Technology
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• 제9권4호
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• pp.211-222
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• 1977

고준위 방사성 폐액의 고화처리 방법들 중 하나인 Vitrification Process의 연구로서 핵연료 재처리 과정에서 유출되는 가상적인 비활성폐액 중에 함유되어 있는 분열 및 부식 생성물들의 질산화물과 유리화시키기 위해 사용되는 첨가제의 열분해에 관하여 연구 조사되었다. 결정수를 갖고 있는 화합물들의 열분해시점은 75$^{\circ}C$이하였지만, 무수화합물들은 비교적 높은 분포를 보였다. 110$0^{\circ}C$까지 가열하여 얻어진 질량손실율을 이론치와 비교하였을 때, 대부분의 화합물은 릴치하거나 근사하였지만, Sodium, Cesium, Lithium, Ruthenium 등의 질산화물의 질량손실율은 이론치 보다 훨씬 높았다. 여기서 얻어진 결과는 고준위 폐액의 가소처리과정 또는 조사된 화합물들의 혼합에 따른 열분해를 분석하는데도 이용될 수 있을 것이다.

• 한국안전학회지
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• 제16권2호
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• pp.75-79
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• 2001

For handling and storage of reactive chemicals, the hazard evaluations have been extremely important. In the chemical industry, the most concerns are focused on the thermal harzards such as runaway reactions and thermal decompositions, which are mostly governed by thermodynamics and reaction kinetics or these reactive chemical in the system. This study no investigated the thermal decomposition characteristics of nitrophenylhydrazine isomers by using differential scanning calorimeter(DSC) and accelerating rate calorimeter(ARC). Experimental results showed that exothermic onset-temperatures in nitrophenylhydrazine(NPH) isomers were about 160-$210^{\circ}C$ by DSC and 100-$150^{\circ}C$ by ARC. The decomposition temperature acquired by ARC was about 50-$60^{\circ}C$ lower than that by DSC. Reaction heats were about 40-100cal/g by DSC and 330-750ca1/g by ARC. While ortho isomer of NPH show two distinct exothermic peaks, para isomer shows a single peak in DSC curves. The first exothermic peak for 2-NPH is mainly due to intramolecular dehydration forming 1-hydroxybenzotriazole(HOBT) and the second exothermic peak is mainly due to the decomposition of HOBT formed in the first step of decomposition. The exothermin peak in the DSC curve for 4-NPH is mainly due to dissociation of hydrazino and nitro groups.