Thermal decomposition of the copolymer of butyl methacylate(BMA) with styrene(St) was investigated. The copolymer Was obtained at 80 ℃ in a continuous stirred tank reactor(CSTR) using toluene and benzoyl peroxide(BPO), as solvent and initiator, respectively. The reactor volume was 0.3 liters and residence time was 3 hours. The thermal decomposition followed the second order kinetics for BMA/St copolymer. The activation energies of thermal decompositon were in the ranges of 38 ~43 kcal/mol for BMA with St copolymer and a good additivity rule was observed with the composition of copolymer. The thermogravimetric trace curve agreed well with the theoretical calculation.

카올린을 용해시킨 황산용액을 에탄올에 주입함으로써 알루미늄황산염의 침전물, AI2(SO4)3·18H2O을 제조하고, 그것의 열분해거동을 검토하였다. 합성된 고순도의 침전물은 약 2μm크기의 판상형태의 입자들로 구성되어져 있었다. 에탄올속으로 카올린을 용해시킨 황산용액의 주입속도를 증가시킴에 따라서 생성된 침전물의 결정사 크기는 감소하였다. 침전물의 탄수 및 탄황산에 대한 겉보기 활성화에너지는 각각 11.9Kcal mol-1 과 48.2kcal mol-1 이었다.

YIG 전구체 분말은 요소의 열분해반응을 이용한 균일침전법에 의해서 질산염으로부터 제조하였다. 침전은 철이온이 먼저 침전한 후 이트륨이온이 침전하는 과정으로 이루어졌다. YGI전구체 분말은 철산화물과 비정질로 구성되어 있으며 그 분말의 대략적인 화학식은 2.5Fe2O3.Y3(OH)9-2x(CO3)x.nH2O로 되어있다. YIG 전구체 분말의 열분해과정은 dehydration, 철산화물의 recrystallization, yttrium carbonate 및 yttrium oxide의 형성과 고상반응등 여러단계로 구성되어 있다. 열처리온도가 증가함에 따라 Y2O3와 Fe2O3의 고상반응에 의해 YFeO3 intermediate을 경유해서 YIG상이 형성됨을 확인하였다. 단일상의 YIG는 1200˚C에서 6시간 공기중에서 소성함에 의해서 얻을 수 있었다.

In this study the calcined condition and characteristic of Cu-Ni-Zn ferrite powder were investigated. The Cu-Ni-Zn ferrite powder has been synthesized by the thermal decomposition of the organic acid salt. This process did not require a strict pH control and provided the uniform composition and fine powder with about 0.3 . The XRD diffraction pattern of this powder showed about 50% spinel phase. The optimum calcination was found to be done at for one hour. After the calcination, the amount of spinel increased to 90%. The distribution of the particle size showed bimodal peaks, one was about 0.5 and the other was about 20 . The large particles of 20 were the agglomeration of fine Particles. The mean Particle size of the powder was about 0.4 . The powder was compacted under 100 MPa pressure and sintered at 1100~ for one hour in air. The density of ferrites specimen was a function of the sintering temperature. The higher the temperature, the denser the ferrite. The maximum relative density of the sintered ferrite was about 93% at . The grain size of sintered specimen at was 5 and homogeneous.

수산화물법에 의해 제작된 α-stannic acid의 열분해 거동과 SnO2분말의 성질에 미치는 잔류염소이온의 영향을 관찰하였다. SnCl4와 NH4OH 수용액을 중화시켜 α-stannic acid침전물을 제작하고 NH4NO3수용액으로 세척하였다. 분말내의 잔류 염소이온의 양을 주절하기 위하여 세척정도를 3단계로 조정하였다. 세척후 100˚C에서 건조하고, 500˚C ~ 1100˚C에서 하소함으로써 SnO2분말을 제조하였다. α-stannic acid의열분해 거동ㅇ르 DT-TGA 와 FTIR을 통하여 관찰하고, SnO2분말의 조성과 입자크기 및 비표면적을 각각 AES, TEM 및 BET을 통하여 측정하였다. 잔류 염소이온 양이 감소되면, 저온 하소시 일차입자의 상대적 크기가 커지는 반면 고온하소시에는 상대적으로 감소되었ㄷ. 잔류 염소이온의 일부는 α-stannic acid내의 격자산소 자리에 위치함으로써, 저온가열시 결정수탈리와 결정화를 지연시키고 또한 고온가열시에는 이의 증발에 의해 산소공공이 생성되어 소결을 촉진시킨다고 제의하였다.

The Stockholm Convention, which was adopted in Sweden in 2001 to protect human health and the environment, includes regulations for Persistent Organic Pollutant Rotors such as toxic and bioaccumulatives. Currently, there are 28 types of materials. This prohibits and limits the production, use, and manufacture of products. Korea is a member of the Convention, and it is necessary to prepare management and treatment plans to address the POP trends. Thus, we experimentally investigate whether the environmentally stable incineration is achieved when the sample is thermally treated using the Lab-scale (1 kg/hr). The target samples is pesticides in liquid phase and solid phase. In this study, organic chlorinated pesticides and their thermal characteristics were analyzed. We calculated the theoretical air volume based on the element analysis results. Because the interior of the reactor is small, more than 10 times of the air ratio was injected. The retention time was set to at least 4 seconds using a margin. The incineration temperature was 850℃ and 1100℃. Thus, we experimentally investigated whether the environmentally stable incineration was achieved when the sample was thermally treated using the Lab-scale (1 kg/hr). We analyzed five types of exhaust gas; the 02 concentration was high, but the CO amount decreased. Complete combustion is difficult because of the small size of the furnace due to the nature of Lab-scale. The organic chlorine-containing pesticide had an average decomposition rate of 99.9935%. Considering the decomposition rates of organic chlorine-containing pesticide in this study, the incineration treatment at over 2 ton/hour, which is typical for a conventional incinerator, is possible. Considering the occurrence of dioxins and unintentional persistent organic pollutants, it can operate at more than 1,100℃.

글로우 고압 방전 방식에 의한 저온 플라즈마(Non-thermal Plasma, NTP) 공정은 액상에서 광전자, 전자, OH-라디칼, 전자기 에너지 등 반응성이 높은 화학물질의 형성할 수 있다. 이 NTP는 공기를 carrier 가스로 활용하여 반응성이 높은 화학종을 생성하는데, 유기물을 효과적으로 산화시키는 고도산화공법의 일종이다. NTP의 강력한 산화력에도 불구하고, NTP 공정에서 발현되는 오염물질의 분해 메커니즘과 그 중간부산물 및 최종 생성물의 경로는 명확하게 밝혀지지 않아 연구가 필요한 실정이다. 본 연구는 폐수 내 다양한 오염물질이 어떠한 메커니즘으로 분해되는가를 실험적으로 규명하고, 2종(sulfamethazine sodium salt와 sulfathiazole sodium salt)의 sulfonamide 계열 항생제에 NTP 공정을 적용하여 제거성능과 분해경로를 검증한다. 또한, 대상 항생제의 분해가 폐수처리 과정에서의 분해 동역학 및 생태 독성과 어떻게 관련되는지를 확인하기 위해 주요 중간부산물 및 신규생성물의 fate를 확인한다. NTP 공정의 진보된 효과를 증명하기 위해 반응성 화학종인 과산화수소 (H2O2)의 순간 생성량을 정량하였으며, OH-라디칼 생성의 간접지표인 N-Dimethyl-4-Nitrosoaniline (RNO) 물질의 분해동역학적 성질을 바탕으로 분해속도계수를 산출하였다. H2O2의 농도는 초기 NTP 공정 적용 시 300 mg/L 까지 증가하였고, 1440 min 적용 시 약 12 mg/L로 감소하며 OH-라디칼 생성과 오염물질 분해에 관여하는 것을 확인하였다. 또한 RNO 물질은 일차함수 형태로 감소하며, 0.91/hr의 속도로 제거되었다. LC-MS/MS (6410 LC-ESI/MS/MS (QQQ), Agilent, USA) 분석을 통해 검출된 중간부산물과 신규생성물을 통해 분해경로를 확인하였다. 문헌과 실험결과의 비교는 NTP 공정이 OH-라디칼 발생 및 산화 환원제와 반응종의 상호 작용으로 인한 산화력 측면에서 다른 산화 공정보다 우수함을 보여준다. Daphnia magna를 이용한 생태독성(Toxicity Unit, TU) 결과는 폐수처리에 대한 NTP 공정 적용이 반응성 화학종의 생성촉진을 통해 독성의 저감에 기여함을 보여주며, 실험결과 TU 값은 초기 2.2 대비 24 hr 적용 후 0.8로 크게 감소하였고, 충분한 체류 시간이 핵심 설계요소임을 밝혔다. 궁극적으로 본 연구는 항생제의 효과적인 제어 및 부산물 관리방안에 대한 유용한 정보를 제공한다.

광액시료와 비-자성광액시료에 포함된 황비철석을 자류철석으로 상변환 시키기 위하여 그리고 비소 함량을 2,000 mg/kg 이하로 제거하기 위하여 마이크로웨이브 장치를 다양한 시간으로 가열하였 고, 습식-자력선별하였다. 마이크로웨이브 가열시간이 증가함에 따라 황비철석 표면의 가장자리부터 자류철석으로 상변환이 일어났고, 열점 현상에 의하여 자류철석 내부에 용융공극과 마이크로-크랙들 이 형성되었다. 마이크로웨이브 가열을 10분간 수행한 광액시료(비소 함량 : 14,732.66 mg/kg)와 비- 자성 광액시료(비소 함량 : 19,970.13 mg/kg)를 습식-자력선별하여 자성광물로 분리시킨 결과, 10분 가열한 자성광물 시료에서 만 비소 함량이 2,000 mg/kg 이하로 나타났다. 따라서 향후 비소 페널티 부과 대상인 복합황화광물을 마이크로웨이브 가열과 습식-자력선별을 효과적으로 활용하면, 비소 함 량을 페널티 부과대상 이하의 광석광물을 얻을 수 있을 것으로 기대한다.

Since HFCs does not contain Cl component, they are not harmful to the depletion of Ozone layer but require reduction especially due to the high GWP (global warming potential). The HFC 134a, known as one of typical refrigerant of HFCs is generally shown to be effectively thermally decomposed only above the temperature of 3,000oC. However, giving condition of sufficient water vapor and the temperature more than 800oC with large heating source like in calcination reactor or blast furnace, the thermal decomposition of HFC 134a will occur easily due the component of H and O contained in water vapor. In order to investigate this phenomenological finding appeared in large scale field test, a series of experimental investigation has been made for the thermal decomposition rate of HFC 134a as a function oxygen and HFC 134a flow rate for a small tubular reactor. In this experiment the wall temperature of tubular reactor was fixed to be 900oC. In order to verify and figure out the finding by experiment, numerical calculation has also been made for the detailed reaction of HFC 134a inside the tubular reactor. The comparison between experiment and numerical calculation are in good agreement each other especially for the rate of thermal destruction at the exit of the reactor. Further, considering the efficient thermal decomposition of HFC 134a in the H2O vapor environment with sufficient heating source, the application of the stoichiometric mixture of hydrogen and oxygen, that is, H2+ 1/2O2, is made numerically in the same tubular reactor, for the thermal decomposition of HFC 134a. The result appears physically acceptable and looks promising for the future method of the HFCs decomposition.

Proper management of refrigerant mixtures containing chlorine and fluorine are gaining worldwide interest in the recent years as, they contribute to global warming and ozone depletion. according to the Montreal Protocol, developed nations have substituted HCFCs in refrigerators and air conditions synthetic greenhouse gas (SGGs) refrigerants such as, R-10 (CCl4), R-23 (CHF3), and R-134a (CH2FCF3). SGGs contribute to the increasing global warming potential. incineration, conventional treatment method of R-134a leads generation of Freon gas, due to excess air during the deacon reaction and due to the flame inhibition of the halogen compound. Therefore, this study proposes on the effective thermal treatment (high-temperature pyrolysis) of R-134a using numerical analysis. R-134a is usually known to have reaction characteristics which degrade only at temperatures reaches 800℃ and contains sufficient moisture in the furnace, HFC-134a refrigerant is treated efficiently by following chemical reaction. C2H2F4+4H2O → 4HF+3H2+3CO2, 4HF+2Ca(OH)2 → 2CaF2+4H2O in this study numerical calculation is performed for the relevant variables. As a result, very positive preliminary results showed about HFC-134a refrigerant treatment. Base on this, in the following study, organized variable research and demonstration experiment will be performed.

Tetrafluoromethane(CF4) have been widely used as etching and chemical vapor deposition gases for semiconductor manufacturing processes. CF4 decomposition efficiency using microwave system was carried out as a function of the microwave power, the reaction temperature, and the quantity of Al2O3 addition. High reaction temperature and addition of Al2O3 increased the CF4 removal efficiencies and the CO2/CF4 ratio. When the SA30 (SiC+30wt%Al2O3) and SA50 (SiC+50wt%Al2O3) were used, complete CF4 removal was achieved at 1000℃. The CF4 was reacted with Al2O3 and by-products such as CO2 and AlF3 were produced. Significant amount of by-product such as AlF3 was identified by X-ray powder diffraction analysis. It also showed that the γ-Al2O3 was transformed to α-Al2O3 after microwave thermal reaction.

The generation of TiO2 nanoparticles by a thermal decomposition of titanium tetraisopropoxide (TTIP) was carried out experimentally using a tubular electric furnace at various synthesis temperatures (700, 900, 1100 and 1300℃) and precursor heating temperatures (80, 95 and 110℃). Effects of degree of crystallinity, surface area and anatase mass fraction of those TiO2 nanoparticles on photocatalytic properties such as decomposition of methylene blue was investigated. Results show that the primary particle diameter obtained from thermal decomposition of TTIP was considerably smaller than the commercial photocatalyst (Degussa, P25). Also, those specific surface areas were more than 134.4 m2/g. Resultant TiO2 nanoparticles showed improved photocatalytic activity compared with Deggusa P25. This is contributed to the higher degree of crystallinity, surface area and anatase mass fraction of TiO2 nanoparticles compared with P25.

This study examined the catalytic destruction of 1,2-dichlorobenzene on V2O5/TiO2 nanoparticles. The V2O5/TiO2 nanoparticles were synthesized by the thermal decomposition of vanadium oxytripropoxide and titanium. The effects of the synthesis conditions, such as the synthesis temperature and precursor heating temperature, were investigated. The specific surface areas of V2O5/TiO2 nanoparticles increased with increasing synthesis temperature and decreasing precursor heating temperature. In addition, the removal efficiency of 1,2-dichlorobenzene was promoted by a decrease in heating temperature. However, the removal efficiency of 1, 2-dichlorobenzene was decreased by an anatase to rutile phase transformation at temperatures 1,300℃.