망간산화물상에서 VOCs 촉매연소

서성규,윤형선 國立 麗水大學校 환경문제硏究所 2001 環境硏究論文集 Vol.4 No.-

This study has been investigated the pyrolysis effect of pretreatment gas on Mn-PC(Phthalocyanine) and Mn oxide catalysts for the combustion of methanol and acetaldehyde. TGA thermogram for Mn-PC showed about 88% loss of mass at 419℃. Also, the catalytic activity of the pyrolysed Mn-PC was compared with that of Mn oxides. The catalysts were characterised by performing thermogravimetric analysis(TGA) and X-ray diffraction(XRD) before and after they had been exposed in the presence of air or air and methanol mixture at 450℃. After pyrolysis of Mn-PC, Mn_(3)O_(4) in the presence of air at 450℃, there was a formation of new manganese oxide phase, Mn_(3)O_(4), Mn_(2)O_(3) confirmed by XRD, respectively. In the blank test of metahnol and acetaldehyde combustion, reactants conversion was not observed up to 440℃ and 320℃, respectively. The relative catalytic activity of Mn oxides on acetaldehyde combustion was summarized as following: MnO <MnO_(2) <Mn_(2)O_(3) <Mn_(3)O_(4). Catalytic activity of Mn_(3)O_(4) is better than of commercial catalysts (CK-306, CK-307) over 260℃.

Cu-Mn 혼합산화물 상에서 일산화탄소의 저온산화반응

조경호(Kyong Ho Cho),박정현(Jung-Hyun Park),신채호(Chae-Ho Shin) 한국청정기술학회 2010 청정기술 Vol.16 No.2

Mn/sand 촉매를 활용한 폴리프로필렌 촉매 열분해 연구

김수현,백승훈,이루세,박상준,손정민 한국청정기술학회 2023 청정기술 Vol.29 No.3

본 연구는 ‘열매체 및 가스 순환형 열분해 시스템’ 개발 목적으로 열분해 실험을 진행하기 전, 공정 모사용 기본 데이터 확보를위해 수행되었다. 폐플라스틱 대체 물질로 폴리프로필렌(Polypropylene, PP)을 열분해 시료로 사용하였으며, 본 시스템에서열전달 매체로 활용되는 유동사(이하 sand)를 사용하였다. 촉매 열분해 실험을 수행하기 위해 Mn계 물질(이하 Mn)을 촉매로선택하였으며, sand에 담지하여 촉매 열분해 실험을 수행하였다. 열중량 분석기(Thermogravimetric analyzer, TGA)를 이용하여 PP의 기본 물성을 분석하였고, 질소 분위기 600℃ 조건에서 촉매 열분해를 통해 액상 오일을 생성하였다. 생성된 액상 오일은 GC/MS 분석을 통해 탄소 수 분포를 확인하였다. 본 연구에서는 Mn 담지 유무와 함량 변화에 따른 액상 오일 수율과 오일내 탄화수소 분포에 미치는 영향을 조사하였다. Mn/sand를 이용하면 sand를 단독으로 활용한 열분해와 비교하여 잔여물이 감소하고 오일 수율이 증가하였다. 또한 Mn 함량 증가에 따라 액상 오일 내 C6~C9 범위 휘발유 비율이 점차 증가하였으며, 오일내 C10보 다 탄 소 수 가 큰 경 유 및 heavy 오일 분포가 감소하는 것으로 확인되었다. 종합하면, Mn을 촉매로 활용하고 함량 변화를 통해 액상 오일 회수량을 증가시키고 생성물 내 휘발유 비율을 증가시킬 수 있을 것으로 판단하였다. This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C6~C9 range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C10 in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

Mn-doped ZnGa_2(O_4)및 CdGa_2O_4결정의 광학적 에너지 간격

최성휴,방태환,김남오 한국물리학회 2011 새물리 Vol.61 No.9

An X-ray diffraction (XRD) analysis revealed that the ZnGa_2(O_4):Mn and the CdGa_2O_4:Mn crystals had a cubic structure. The lattice constant of these compounds were a = 8.328Å for the ZnGa_2(O_4):Mn rystal and a = 8.606Å for the CdGa_2(O_4):Mn crystal. The optical absortion spectra obtained near the fundamental absorption edge showed that these compounds had a direct energy band gap. The direct optical energy gaps of the ZnGa_2(O_4):Mn and the CdGa_2(O_4):Mn crystals were given as E_(gd)= 4.119 eV and E_(gd)= 3.678 eV, respectively, at 298 K. ZnGa_2(O_4):Mn 및 CdGa_2O_4:Mn (1.00mol%) 결정을 성장하여성장된 결정의 구조와 격자상수 및 광학적 에너지 간격을 구하였다. 성장된 결정은 cubic의 결정구조를 갖고 있으며 ZnGa_2(O_4):Mn및CdGa_2O_4:Mn (1.00mol%) 결정의 격자상수를 구하면 a = 8.328Å, a = 8.606Å이었다. 이들 결정의 광흡수 spectrum은측정시료의 온도를 298 K로 유지하고, 200~850 nm 파장영역에서측정하였으며 기초 흡수단 영역에서 측정된 광흡수 스펙트럼으로부터광학적 에너지 간격을 계산하였다. ZnGa_2(O_4):Mn 및CdGa_2O_4:Mn 결정의 직접전이 광학적 에너지 간격은 E_(gd) =4.119 eV, E_(gd) = 3.678 eV으로 각각 나타났다.

BiFeO₃박막의 Dy-, Mn-치환 효과에 대한 물리적 특성

배유라,김진원,도달현,김상수 한국물리학회 2011 새물리 Vol.61 No.4

We prepared pure BiFeO₃and Dy and Mn-doped BiFeO₃ (Bi_(0.9)Dy_(0.1)FeO₃,Bi(Fe_(0.975)Mn_(0.025)O_(3-δ)and (Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)thin films on Pt(111)/Ti/SiO₂ /Si(100) substrates by using a chemical solution deposition method. The coated thin films were annealed at 550℃ for 30 min by using a conventional annealing process under a nitrogen atmosphere, and the changes in the microstructure and the electrical properties with doping were investigated. The remnant polarization (2P_r) and the coercive field (2E_c) of the Dy- and Mn-codoped BiFeO₃,Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ), thin film were 47 μC/cm² and 741 kV/cm respectively at an applied electric field of 1060 kV/cm. The leakage current density of the BiFeO₃and the Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ) thin films were 2.58 ×10^(−3) A/cm² and 1.41×10^(−5) A/cm²,respectively at 100 kV/cm, and their dielectric constants and dielectric losses of the thin films were 140 and 0.049, and 152 and 0.037 at 1 kHz, respectively. The good ferroelectric properties observed in the Dy- and Mn-codoped BiFeO₃ thin film may be related to a reduction in the numbers of bismuth vacancies and oxygen vacancies. 화학 용액 증착법으로 Pt(111)/Ti/SiO₂/Si(100) 기판 위에 순수한BiFeO₃박막과 BiFeO₃의 Bi^(3+), Fe^(3+) 이온 일부를Dy^(3+), Mn^(2+) 이온으로 치환한 (Bi_(0.9)Dy_(0.1)FeO₃,Bi(Fe_(0.975)Mn_(0.025)O_(3-δ),Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막을 성장시켰다. 성장된 박막은 550 ℃의 질소 분위기에서통상적인 방법으로 열처리 하였으며 치환에 따른 박막의 구조와 강유전및 유전, 전류 특성 등 전기적 특성의 변화를 측정, 비교 분석 하였다. Dy와 Mn으로 동시에 치환한Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막시료의 전기적 특성이 순수한 BiFeO₃의 특성에 비해 크게향상되었는데 외부 전기장 1060 kV/cm 일 때 잔류 분극 (2P_r) 과항전기장 (2E_c) 값이 각각 47μC/cm², 741 kV/cm이었다. 또순수한 BiFeO₃박막과Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막의 누설 전류 밀도는 외부 전기장 100 kV/cm일 때 각각 2.58×10^(-3) A/cm², 1.41×10^(-5) A/cm²이었으며, 1 kHz에서 유전상수와 유전손실 값은 각각 140, 0.049 과 152,0.037이었다. 이와 같이 Dy와 Mn으로 동시에 치환한 박막이 좋은 전기적특성을 보이는 것은 치환에 의해서 비스무스 빈자리와 산소 빈자리 수가감소하였기 때문이라고 보여진다.

Composition Dependence of Structural and Magnetic Properties of Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C (0 ≤ x ≤ 1)

Ying-Hua Liang,Ping-Zhan Si,Ting-Ting Qi,Xin-You Wang,Fei-Yang Wang,Qiong Wu,Hong-Liang Ge,Jihoon Park,Chul-Jin Choi 한국자기학회 2024 Journal of Magnetics Vol.29 No.1

Both Mn₄C (=Mn₃MnC) and Mn₃GaC have been studied previously. However, the reports on Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C (0 ≤ x ≤ 1) with intermediate compositions are very rare. In this work, the structure and magnetic properties of Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C prepared by using solid state reaction were studied systematically. High purity anti-perovskitetype Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C were obtained in the composition range of 0 ≤ x ≤ 0.5, above which Mn₂₃C₆ precipitates and the fraction of Mn₂₃C₆ in the samples increases with increasing x. The structural stability, lattice parameters, and room temperature saturation magnetization of ferromagnetic Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C (0 ≤ x ≤ 1) decreases with increasing x. The Curie temperature of Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C (0 ≤ x ≤ 1) increases with increasing x. Most Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C with varied x exhibit near-zero coercivity and zero remanent magnetization. This work indicates that the temperature coefficient of magnetization of Mn<SUB>3+x</SUB>Ga<SUB>1-x</SUB>C may be tuned by tuning the fraction of the Ga atoms.

Mn-Ce계/TiO₂ 촉매에 의한 아세트산의 습식산화 반응특성

박기선,박종원,김영주,윤왕래,박종수,이영우,강용,Park, K.S.,Park, J.W.,Kim, Y.J.,Yoon, W.L.,Park, J.S.,Rhee, Y.W.,Kang, Y. 대한환경공학회 2000 대한환경공학회지 Vol.22 No.12

희분식 고온/고압 미분반응기를 이용하여 습식산화 반응시 대표적 난분해성 중간 산화물질로 알려진 아세트산을 산화반응 기질로 하여 여러 가지 담체 및 촉매의 조합에 대한 산화반응성을 실험하였다. 사용된 담체는 다공성 실리카($SiO_2$), 티타니아($TiO_2$), 지르코니아($ZrO_2$), $ZrSiO_4$, $ZrO_2(10wt%)/TiO_2$ 등이었으며 촉매활성성분온 크게 Ru, Mn, Ce의 세 가지로서 단독 혹은 조합사용(2성분계 및 3성분계)시의 산화활성에 대하여 조사하였다. 이를 통하여 일차척인 활성이 우수한 것으로 나타난 $Mn(2.8)-Ce(7.2wt%)/TiO_2$ 혹은 $Ru(0.5)-Mn(2.7)-Ce(6.8wt%)/TiO_2$ 기준촉매의 활성증진을 위하여 p-type 반도체 물질(CoO, SnO 및 $Ag_2O$)를 첨가제로 소량 사용함으로써 이에 따른 습식산화 반응 상대 활성실험을 수행하였다. 우선, $Mn-Ce/TiO_2$ 기준촉매에 있어서, p-type 반도체 물질(CO, Sn Ag)을 첨가한 경우, 모두 활성증진효과를 보이며 크기 정도는 Co> Ag >Sn순이었다. 특히, $Mn(2.7)-Ce(6.8)-Co(0.5wt%) /TiO_2$에 있어서는 약 2.6배의 높은 활성상승이 나타났다. 이의 가시적인 주원인은 표면적 증가 및 시너지 효과에 기인하는 것으로 판단되었다. $Ru-Mn-Ce/TiO_2$ 기준 촉매에 있어서는 $Ru(O.5)-Mn(2.4)-Ce(6.1)-Co(1.0wt%)/TiO_2$에서만 활성증진효과를 보였으며 그 이외의 다른 경우에 있어서는 표면적 및 활성감소가 일어났다. Catalytic wet air oxidation of acetic acid over Mn-Ce based catalysts deposited on various supports ($SiO_2$, $TiO_2$, $ZrO_2$), $ZrSiO_4$, $ZrO_2(10wt%)/TiO_2$) have been carried out in high pressure microreactors. Also, promotional effects by small addition(O.5~1.0 wt%) of p-type semiconductors (CoO, $Ag_2O$, SnO) have been investigated. From the screening tests for initial activity ranking, both Mn(2.8)-Ce(7.2 wt%) and Ru(O.4)Mn(2.7)-Ce(6.9 wt%) supported on $TiO_2$ were selected as the promising reference candidates. In $Mn-Ce/TiO_2$ reference catalyst, addition of small amount of each p-type semiconductor (Co, Sn and Ag) resulted in activity promotional effect and the degree of the increase was in the following order: Co> Ag > Sn. Especially, $Mn-Ce/TiO_2$ promoted with 0.5 wt% Co gave the 2.6 folds activity increase compared to the reference case attributing to the surface area increase as well as synergy effect. In $Ru-Mn-Ce/TiO_2$ reference catalyst, only Co(1.0 wt%) promoted case showed a little reaction rate increase.

Electron Spin Resonance Study of Mn-doped Metal Oxides Annealed at Different Temperatures

판더롱,P. Zhang,H. D. Tran,유성초 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.5

We investigated the influence of the annealing temperature (Tan) on the electron spin resonance (ESR) spectra of some Mn-doped metal oxides. Samples of MgO, CaO, BaO, SrO, PbO, CuO, NiO, ZnO, Y2O3, Dy2O3, TiO2, and ZrO2 doped with 2.0-at.% Mn were annealed at temperatures of 400 - 1400 ℃. Their ESR spectra were found to depend strongly on the Tan and the oxide host lattices. PbO:Mn, Y2O3:Mn, and Dy2O3:Mn did not show any ESR signal with changing Tan. Meanwhile, the ESR spectra of MgO:Mn, CaO:Mn, BaO:Mn, SrO:Mn, CuO:Mn, ZnO:Mn, NiO:Mn, TiO2:Mn, and ZrO2:Mn revealed a remarkable change in shape at a temperature Ttr between 500 and 800 ℃. At temperatures Tan ∼ Ttr, MgO:Mn, CaO:Mn, ZnO:Mn exhibited Mn2+ hyperfine lines while SrO:Mn, BaO:Mn, CuO:Mn, NiO:Mn, TiO2:Mn, and ZrO2:Mn exhibited symmetrical and/or asymmetrical lines. However, most samples showed no ESR signal for Tan < Ttr. The nature of these phenomena was discussed.

소나무 묘목의 생장 및 영양상태에 미치는 Mn의 영향

이충화,이승우,진현오,정진현,이천용 한국생태학회 2002 Journal of Ecology and Environment Vol.25 No.5

Mn 처리에 대한 소나무 묘목의 생장 및 영양상태의 반응을 수경재배법에 의하여 조사하였다. Mn 처리 농도별(0, 30, 60ppm) 배양액의 pH를 4.0으로 조절한 후, 소나무(Pinus densiflora) 2년생 묘목을 배양액에 이식하여 90일 동안 온실에서 생육시켰다. 소나무 묘목의 건물생장은 Mn 처리에 의하여 감소하였으며, 상대생장율(RGR)과 순동화율(NAR) 감소에 대한 Mn의 영향이 인정되었다. 이러한 결과는 배양액의 Mn 농도 증가에 의해 잎의 건물생산효율이 저하되었다는 것을 시사하였다. 식물체내 원소함량에 대한 Mn의 영향을 조사한 결과, 소나무 묘목의 줄기와 뿌리내 Ca 및 Mg 함량은 Mn 60ppm 처리구에서 가장 낮았으며, Mn 농도는 뿌리에 비하여 잎에서 3배 가량 높은 함량을 나타내었다. 또한 무처리구에 비해 Mn 처리구에서 순광합성 속도의 감소가 나타났다. 이상의 결과는 뿌리의 양분 흡수저해 및 뿌리에서 잎으로 이행된 Mn의 과잉축적에 의한 광합성 저해를 반영하는 것으로써, 결과적으로 소나무 묘목의 건물생장량 감소가 이들 결과의 복합적인 영향에 의해 초래되었음을 시사한다. The effects of Mn on growth and nutrient status of Pinus densiflora seedlings grown in a nutrient culture solution were investigated. Mn concentrations was added as manganese chloride at 0, 30 and 60ppm to the nutrient culture solution. The 2-year-old seedlings were transplanted into the solution maintained at pH 4.0, and grown for 90 days in a greenhouse. The Mn treatment induced a significant reduction in the dry weight growth of the seedlings. The relative growth rate(RGR) and net assimilation rate(NAR) of the seedlings decreased with increasing Mn concentrations in the nutrient culture solutions. For the nutrient status of the seedlings, Ca and Mg content in trunk and root was least in 60ppm Mn treatment, and Mn content in needle was about 3 times more than in root. Also the net photosynthetic rate of the seedlings was significantly lower both in 30ppm and 60ppm Mn treatment compared to them in 0ppm. This result suggests that the reductions in the RGR and NAR of the seedlings may be resulted from the inhibition of net photosynthesis by the mixed effect of lower nutrient uptake of roots and excess accumulation of Mn in needle.

Mn-doped Zn/Al layered double hydroxides as photocatalysts for the 4-chlorophenol photodegradation

Morales-Mendoza, G.,Tzompantzi, F.,Garcia-Mendoza, C.,Lopez, R.,De la Luz, V.,Lee, S.W.,Kim, T.H.,Torres-Martinez, L.M.,Gomez, R. Elsevier 2015 Applied clay science Vol.118 No.-

Mn-doped Zn/Al layered double hydroxides (LDH) with Mn 0.5-3.0% mol respect to Zn content with improved photocatalytic degradation of 4-chlorophenol (4Clphenol) were studied. The characterization studies showed the isomorphic incorporation Mn as dopant until 1% mol. The 4Clphenol degradation was proposed as result of a combined effect of oxidation by both hydroxyl radicals (OH?) and photogenerated holes (h<SUP>+</SUP>). In a proposed mechanism it is suggested that Mn enhances the charge separation acting as electron e<SUP>-</SUP> (Mn<SUP>3+</SUP>; Mn<SUP>4+</SUP>) or hole h<SUP>+</SUP> (Mn<SUP>2+</SUP>; Mn<SUP>3+</SUP>) traps according to its oxidation state. Exhaustive characterization through EDS, XRD, UV-vis-DRS, TEM-Dark field STEM, fluorescence spectroscopy for OH? detection and XPS, has been done denoting the importance of the Mn content and its different oxidation states in the photophysical and photocatalytic properties of the Mn-doped Zn/Al-based layered double hydroxides.