• 제목/요약/키워드: SO2

검색결과 2,425건 처리시간 0.034초

Study of molecular motion by 1H NMR relaxation in ferroelectric LiH3(SeO3)2, Li2SO4·H2O, and LiN2H5SO4 single crystals

  • Park, Sung Soo
    • 한국자기공명학회논문지
    • /
    • 제20권1호
    • /
    • pp.1-6
    • /
    • 2016
  • The proton NMR line widths and spin-lattice relaxation rates, $T_1^{-1}$, of ferroelectric $LiH_3(SeO_3)_2$, $Li_2SO_4{\cdot}H_2O$, and $LiN_2H_5SO_4$ single crystals were measured as a function of temperature. The line width measurements reveal rigid lattice behavior of all the crystals at low temperatures and line narrowing due to molecular motion at higher temperatures. The temperature dependences of the proton $T_1^{-1}$ for these crystals exhibit maxima, which are attributed to the effects of molecular motion by the Bloembergen - Purcell - Pound theory. The activation energies for the molecular motions of $^1H$ in these crystals were obtained. From these analysis, $^1H$ in $LiH_3(SeO_3)_2$ undergoes molecular motion more easily than $^1H$ in $LiN_2H_5SO_4$ and $Li_2SO_4{\cdot}H_2O$ crystals.

NO의 암모니아 선택적 촉매환원반응을 위한 철 제올라이트 촉매의 내황성에 미치는 조촉매 효과 (The Effect of Promoter on the SO2-resistance of Fe/zeolite Catalysts for Selective Catalytic Reduction of NO with Ammonia)

  • 하호정;최준환;한종대
    • 청정기술
    • /
    • 제21권3호
    • /
    • pp.153-163
    • /
    • 2015
  • Fe/제올라이트 촉매의 저온에서의 NO의 암모니아 선택적 촉매환원반응 활성에 미치는 반응가스 중의 수분과 SO2의 영향을 조사하였다. Fe/제올라이트 촉매에 조촉매로 Mn, Zr과 Ce를 첨가한 Fe/제올라이트 촉매로 수분과 SO2가 포함된 저온에서의 NO의 암모니아 선택적 촉매환원반응에서 조촉매 첨가효과를 조사하였다. 조촉매는 이온교환법으로 철을 담지시킨 Fe/제올라이트 촉매에 건식 함침법으로 첨가하였다. 제올라이트는 디젤엔진에서의 SCR기술의 적용을 위하여 NH4-BEA와 NH4-ZSM-5을 사용하였다. 촉매의 특성은 BET, XRD, SEM/EDS와 TEM/EDS를 사용하여 조사하였다. 반응가스 중에 5% H2O와 100 ppm SO2이 존재하는 경우 Fe/BEA 촉매의 NO 전환율은 200 ℃에서 77%에서 47%로 감소하였다. MnFe/BEA 촉매는 수분과 SO2가 존재하는 경우에 200 ℃에서 53% 이상의 NO 전환율을 나타내며 Fe/BEA 촉매보다 우수한 반응활성을 보였다. Mn은 Fe 성분의 분산도를 증가시키고 Fe의 소중합체 형성을 방지하는 효과를 나타내었다. 첨가제는 Mn이 Zr과 Ce보다 우수한 특성을 나타내었다. 250 ℃ 이하의 온도에서 Fe/BEA 촉매가 Fe/ZSM-5 촉매보다 우수한 반응특성을 나타내었다.

무해화된 폐석면에 함유된 유가금속 회수 기술 개발 (Development of Technology for Recovering Valuable Metals in Detoxified Waste Asbestos-Containing Waste)

  • 김동년;양동현;김석찬
    • 공업화학
    • /
    • 제31권4호
    • /
    • pp.438-442
    • /
    • 2020
  • Calcium silicate, larnite, merwinite, akermanite 로 구성된 무해화된 폐석면으로부터 화학적 처리를 통한 유가금속 회수를 위한 성분별 회수 조건, 유가금속 회수 공정 최적화 등에 대한 연구를 수행하였다. DACW (detoxified asbestos-containing waste)의 주성분인 Si, Ca, Mg을 SiO2, CaSO4, Mg(OH)2 화합물 형태로 분리, 회수하였다. 분리된 각 성분은 XRD 및 ICP 분석을 통하여 확인하였다. 성분별 회수 조건은 산을 처리하여 SiO2를 우선 분리하고 연속해서 H2SO4 처리하여 Ca는 황산염인 CaSO4 형태로 회수하였다. 남은 Mg는 강염기 조건에서 Mg(OH)2로 침전시켜 회수하였다. 본 연구는 지정 폐기물인 폐석면을 무해화하여 구성 성분을 회수 하여 매립에 의한 석면 폐기물의 기존 처리 과정을 자원 순환형 녹색 기술로의 전환이 가능함을 제시하였다.

Experimence Study of Trace Water and Oxygen Impact on SF6 Decomposition Characteristics Under Partial Discharge

  • Zeng, Fuping;Tang, Ju;Xie, Yanbin;Zhou, Qian;Zhang, Chaohai
    • Journal of Electrical Engineering and Technology
    • /
    • 제10권4호
    • /
    • pp.1786-1795
    • /
    • 2015
  • It is common practice to identify the insulation faults of GIS through monitor the contents of SF6 decomposed components. Partial discharges (PD) could lead to the decomposition of SF6 dielectric, so new reactions usually occur in the mixture of the newly decomposed components including traces of H2O and O2. The new reactions also cause the decomposed components to differ due to the different amounts of H2O and O2 even under the same strength of PD. Thus, the accuracy of assessing the insulation faults is definitely influenced when using the concentration and corresponding change of decomposed components. In the present research, a needle-plate electrode was employed to simulate the PD event of a metal protrusion insulation fault for two main characteristic components SO2F2 and SOF2, and to carry out influence analysis of trace H2O and O2 on the characteristic components. The research shows that trace H2O has the capability of catching an F atom, which inhibits low-sulfide SFx from recombining into high-sulfide SF6. Thus, the amount of SOF2 strongly correlates to the amount of trace H2O, whereas the amount of SO2F2 is weakly related to trace H2O. Furthermore, the dilution effect of trace O2 on SOF2 obviously exceeds that of SO2F2.

마이크로버블 장치를 이용한 제지공정 소성로 배기 오염물질 처리 (Treatment of Exhaust Pollutants from a Lime Kiln of Paper-mill with Micro-bubble System)

  • 정재억;정용준
    • 한국환경과학회지
    • /
    • 제29권11호
    • /
    • pp.1025-1032
    • /
    • 2020
  • This work was performed to develop a dip injection wet scrubber (DIWS) system with chlorine dioxide as the oxidant. The exhaust pollutants from a lime kiln of paper-mill were introduced to the system. When NaClO3 was used to oxidize NO into NO2, the oxidation was unsatisfactory and the combination of HNO3 or H2SO4 was required for 100% oxidation. ClO2 is recommended to oxidize NO and SO2 effectively. With the combination of 1st stage of DIWS and ClO2, 57.1% of NOx and 98% of SO2 were effectively removed. In the case of 2nd stage of DIWS and ClO2, 93.5% of NOx and 99% of SO2 were removed. The ClO2+DIWS process was superior to the ClO2+Scrubber process in terms of investment, running cost and NOx removal efficiency.

NH3-SCO 반응에서 Vanadium 담지함량이 Pt/V/TiO2 촉매에 미치는 영향 (Effect of Vanadium Loading Amount on Pt/V/TiO2 Catalyst on NH3-SCO Reaction)

  • 김민수;김기왕;홍성창
    • 공업화학
    • /
    • 제33권6호
    • /
    • pp.594-599
    • /
    • 2022
  • 본 연구에서는 Pt/V/TiO2 촉매 제조 시, V 담지 함량에 따른 NH3-SCO (selective catalytic oxidation) 반응 활성을 비교하였다. NH3 전환율 및 N2 선택성을 모두 고려하였을 때, V이 2 wt% 담지된 촉매에서 가장 우수한 성능을 나타내었다. 이에 따라 물리/화학적 특성과 반응활성과의 상관관계를 확인하였을 때, 격자산소종의 증가 및 (V3+ + VM4+) 비율의 증가가 활성인자임을 확인하였다. 또한 가장 우수한 촉매를 이용하여 SO2 내구성 실험을 진행하였을 때, 고농도의 SO2가 주입되더라도 영향이 미미함을 확인하였다.

대기오염물질과 환경성 질환 관련 의료이용률과의 연관성 - 일반거주지역을 대상으로 - (Association between Air Pollutant Levels and Medical Usage Rates of Environmental Disease in a General Residential Area)

  • 박동윤;이채관
    • 한국환경보건학회지
    • /
    • 제47권3호
    • /
    • pp.279-291
    • /
    • 2021
  • Objectives: This study investigated the association between air pollutant levels and medical usage rates for environmental disease in a general residential area during the period 2015-2017. Methods: Air pollutant (PM10, PM2.5, SO2, NO2, CO, O3) data were collected from Air-Korea. Medical usage data on environmental disease (asthma, allergic rhinitis, atopic dermatitis) for the period 2015-2017 in a general residential area in Gyeongsangnam-do Province were provided by the National Health Insurance Corporation. Pearson correlation analysis and multiple regression analysis were conducted to investigate the association between air pollutant levels and medical usage rates (SAS 9.4). In the multiple regression analysis, environmental disease was set as the dependent variable and air pollutants were set as independent variables and analyzed using the General Linear Model. Results: Except for PM2.5, the average concentration of air pollutants in the surveyed area was below than the air environment standards of Korea. NO2 was higher than Korea's national average, but CO was similar. The others were lower than the Korea's national average. The daily medical usage rates for environmental disease were 1.38‰ for asthma, 9.90‰ for allergic rhinitis, and 0.32‰ for atopic dermatitis. As a result of correlation analysis, PM10 and SO2, NO2 and CO were significantly correlated with asthma, PM10 and NO2 and CO were correlated with allergic rhinitis, and PM10 and PM2.5, SO2, NO2 and CO were correlated with atopic dermatitis. As a result of multiple regression analysis, PM10 and SO2 were found to have a higher effect on asthma, PM10 and NO2 on allergic rhinitis, and SO2 and NO2 on atopic dermatitis, compared to other air pollutants. Conclusion: According to these results, air pollutants such as PM10 and SO2 and NO2 were associated with the medical usage rates of environmental disease even in relatively low concentrations. Therefore, continuous monitoring will be required for general residential areas.

Recycling of end-of-life LiNixCoyMnzO2 batteries for rare metals recovery

  • Sattar, Rabia;Ilyas, Sadia;Kousar, Sidra;Khalid, Amaila;Sajid, Munazzah;Bukhari, Sania Iqbal
    • Environmental Engineering Research
    • /
    • 제25권1호
    • /
    • pp.88-95
    • /
    • 2020
  • An investigation of rare metals recovery from LiNixCoyMnzO2 cathode material of the end-of-life lithium-ion batteries is presented. To determine the influence of reductant on the leach process, the cathode material (containing Li 7.6%, Co 20.4%, Mn 19.4%, and Ni 19.3%) was leached in H2SO4 solutions either with or without H2O2. The optimal process parameters with respect to acid concentration, addition dosage of H2O2, temperature, and the leaching time were found to be 2.0 M H2SO4, 4 vol.% H2O2, 70℃, and 150 min, respectively. The yield of metal values in the leach liquor was > 99%. The leach liquor was subsequently treated by precipitation techniques to recover nickel as Ni(C4H7N2O2)2 and lithium as Li2CO3 with stoichiometric ratios of 2:1 and 1.2:1 of dimethylglyoxime:Ni and Na2CO3:Li, respectively. Cobalt was recovered by solvent extraction following a 3-stage process using Na-Cyanex 272 at pHeq ~5.0 with an organic-to-aqueous phase ratio (O/A) of 2/3. The loaded organic phase was stripped with 2.0 M H2SO4 at an O/A ratio of 8/1 to yield a solution of 114 g/L CoSO4; finally recovered CoSO4.xH2O by crystallization. The process economics were analyzed and found to be viable with a margin of $476 per ton of the cathode material.

충남지역 대형사업장의 대기오염물질 확산 특성 파악 (Characterization of Atmospheric Dispersion Pattern from Large Sources in Chungnam, Korea)

  • 최우영;박민하;정창훈;김용표;이지이
    • 한국입자에어로졸학회지
    • /
    • 제17권3호
    • /
    • pp.55-69
    • /
    • 2021
  • Chungnam region accounts for the largest SOX (22.8%) emission with the second-largest NOX (10.8%) emission in Korea due to the integration of many large industrial sources including a steel mill, coal-fired power plants, and petrochemical complex. Air pollutants emitted by large industrial sources can cause harmful problems to humans and the environment. Thus, it is necessary to understand dispersion patterns of air pollutants from large industrial sources in Chungnam to characterize atmospheric contamination in Chungnam and the surrounding area. In this study, seasonal atmospheric dispersion characteristics for SOX, NOX, and PM2.5 from ten major point sources in Chungnam were evaluated using HYSPLIT 4 model, and their contributions to SO2, NO2 concentrations in the regions near the source areas were estimated. The predictions of the HYSPLIT 4 model show a seasonal different dispersion pattern, in which air pollutants were dispersed toward the southeast in winter while, northeast in summer. In summer, due to weaker wind speed, air pollutants concentrations were higher than in winter, and they were dispersed to the metropolitan area. The local emissions of air pollutants in Taean area had a greater influence on the ambient SO2 and NO2 concentrations at Taean, whereas SOX and NOX emissions from large sources located at Seosan showed relatevely little effect on the ambient ambient SO2 and NO2 concentrations at Seosan.