• 제목/요약/키워드: Sulfate ($SO{_4}^{2-}$)

검색결과 807건 처리시간 0.025초

Hydro/solvothermal synthesis, crystal structure, and thermal behaviour of piperazine-templated nickel(II) and cobalt(II) sulfates

  • Kim, Chong-Hyeak;Park, Chan-Jo;Lee, Sueg-Geun
    • 분석과학
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    • 제19권4호
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    • pp.309-315
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    • 2006
  • Two piperazine-templated metal sulfate complexes, $(C_4N_2H_{12})[Ni(H_2O)_6](SO_4)_2$, I and ($C_4N_2H_{12}$) $[Co(H_2O)_6](SO_4)_2$, II, have been synthesized by hydro/solvothermal reactions and their crystal structures analyzed by single crystal X-ray diffraction methods. Complex I crystallizes in the monoclinic system, $P2_1/n$ space group, a=12.920(3), b=10.616(2), $c=13.303(2){\AA}$, ${\beta}=114.09(1)^{\circ}$, Z=4, $R_1=0.030$ for 3683 reflections; II: monoclinic $P2_1/n$, a=12.906(3), b=10.711(2), $c=13.303(2){\AA}$, ${\beta}=114.10(2)^{\circ}$, Z=4, $R_1=0.032$ for 4010 reflections. The crystal structures of the piperazine-templated metal(II) sulfates demonstrate zero-dimensional compound constituted by diprotonated piperazine cations, metal(II) cations and sulfate anions. The structures of complex I and II are substantially isostructural to that of the previously reported our piperazine-templated copper(II) sulfate complex $(C_4N_2H_{12})[Cu(H_2O)_6](SO_4)_2$. The central metal(II) atoms are coordinated by six water molecules in the octahedral geometry. The crystal structures are stabilized by three-dimensional networks of the $O_{water}-H{\cdots}O_{sulfate}$ and $N_{pip}-H{\cdots}O_{sulfate}$ hydrogen bonds between the water molecules and sulfate anions and protonated piperazine cations. Based on the results of thermal analysis, the thermal decomposition reactions of the complex I was analyzed to have three distinctive stages whereas the complex II proceed through several stages.

Characterization of NiSO4 Supported on Fe2O3 and Catalytic Properties for Ethylene Dimerization

  • Pae, Young-Il;Sohn, Jong-Rack
    • Bulletin of the Korean Chemical Society
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    • 제28권8호
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    • pp.1273-1279
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    • 2007
  • The NiSO4 supported on Fe2O3 catalysts were prepared by the impregnation method. No diffraction line of nickel sulfate was observed up to 30 wt %, indicating good dispersion of nickel sulfate on the surface of Fe2O3. The addition of nickel sulfate to Fe2O3 shifted the phase transition of Fe2O3 (from amorphous to hematite) to higher temperatures because of the interaction between nickel sulfate and Fe2O3. 20-NiSO4/Fe2O3 containing 20 wt % of NiSO4 and calcined at 500 oC exhibited a maximum catalytic activity for ethylene dimerization. The initial product of ethylene dimerization was found to be 1-butene and the initially produced 1-butene was also isomerized to 2-butene during the reaction. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.

AFMR 공정을 이용한 광산폐수의 중금속 제거 (Removal of Heavy Metals from Acid Mine Drainage using AFMR Process)

  • 백병천;김광복
    • 대한환경공학회지
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    • 제22권2호
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    • pp.313-321
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    • 2000
  • 본 연구는 AFMR(Anaerobic Floating Media Reactor) 공정을 이용하여 폐광산폐수로부터 중금속을 제거하기 위한 연구로서 본 연구에서는 두 개의 AFMR 반응조를 HRT 3일, COD/sulfate 비는 0.3~0.8, 운전온도는 $30^{\circ}C{\sim}35^{\circ}C$, 알칼리도는 1,000 mg/l(as $CaCO_3$)으로 운전하였다. 실험결과 AFMR 반응조는 COD/sulfate 비 0.5, 운전온도 $35^{\circ}C$에서 환원된 $SO{_4}^{2-}$양/제거된 COD양(mg/mg) 비는 약 1를 유지하였으며, 중금속 Cr, Pb, Fe은 99.99%, Cd 98%, Mn 90%의 제거효율을 나타내었다. 운전온도를 $35^{\circ}C$에서 $30^{\circ}C$로 감온시킬 때 AFMR 반응조내의 환원된 $SO{_4}^{2-}$양/제거된 COD양(mg/mg) 비는 1.37배로 증가하였다. 또한 운전온도 $30^{\circ}C$, COD/sulfate 비는 0.4일 때 최대의 황산염 환원을 보였으며 이때 유입되는 중금속인 Fe, Pb, Cr은 99.99%, Zn, Cd, Cu는 99.9%, Mn 97.3%의 중금속 제거효율을 보였다.

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Prediction of compressive strength of lightweight mortar exposed to sulfate attack

  • Tanyildizi, Harun
    • Computers and Concrete
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    • 제19권2호
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    • pp.217-226
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    • 2017
  • This paper summarizes the results of experimental research, and artificial intelligence methods focused on determination of compressive strength of lightweight cement mortar with silica fume and fly ash after sulfate attack. The artificial neural network and the support vector machine were selected as artificial intelligence methods. Lightweight cement mortar mixtures containing silica fume and fly ash were prepared in this study. After specimens were cured in $20{\pm}2^{\circ}C$ waters for 28 days, the specimens were cured in different sulfate concentrations (0%, 1% $MgSO_4^{-2}$, 2% $MgSO_4^{-2}$, and 4% $MgSO_4^{-2}$ for 28, 60, 90, 120, 150, 180, 210 and 365 days. At the end of these curing periods, the compressive strengths of lightweight cement mortars were tested. The input variables for the artificial neural network and the support vector machine were selected as the amount of cement, the amount of fly ash, the amount of silica fumes, the amount of aggregates, the sulfate percentage, and the curing time. The compressive strength of the lightweight cement mortar was the output variable. The model results were compared with the experimental results. The best prediction results were obtained from the artificial neural network model with the Powell-Beale conjugate gradient backpropagation training algorithm.

CeO2-Promoted Highly Active Catalyst, NiSO4/CeO2-ZrO2 for Ethylene Dimerization

  • Pae, Young-Il;Shin, Dong-Cheol;Sohn, Jong-Rack
    • Bulletin of the Korean Chemical Society
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    • 제27권12호
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    • pp.1989-1996
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    • 2006
  • The $NiSO_4/CeO_2-ZrO_2 $catalysts containing different nickel sulfate and $CeO_2$ contents were prepared by the impregnation method, where support, $CeO_2-ZrO_2$was prepared by the coprecipitation method using a mixed aqueous solution of zirconium oxychloride and cerium nitrate solution followed by adding an aqueous ammonia solution. No diffraction line of nickel sulfate was observed up to 20 wt %, indicating good dispersion of nickel sulfate on the surface of $CeO_2-ZrO_2$. The addition of nickel sulfate (or $CeO_2$) to $ZrO_2$ shifted the phase transition of $ZrO_2$ from amorphous to tetragonal to higher temperatures because of the interaction between nickel sulfate (or $CeO_2$) and $ZrO_2$. A catalyst (10-$NiSO_4/1-CeO_2-ZrO_2$) containing 10 wt % $NiSO_4$ and 1 mole % $CeO_2$, and calcined at $600{^{\circ}C}$ exhibited a maximum catalytic activity for ethylene dimerization. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method. The role of $CeO_2$was to form a thermally stable solid solution with zirconia and consequently to give high surface area, thermal stability and acidity of the sample.

High Time-resolution Characterization of PM2.5 Sulfate Measured in a Japanese Urban Site

  • Ma, Chang-Jin;Kang, Gong-Unn;Kim, Ki-Hyun
    • Asian Journal of Atmospheric Environment
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    • 제9권4호
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    • pp.280-287
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    • 2015
  • The high time-resolution monitoring data are essential to estimate rapid changes in chemical compositions, concentrations, formation mechanisms, and likely sources of atmospheric particulate matter (PM). In this study, $PM_{2.5}$ sulfate, $PM_{2.5}$, $PM_{10}$, and the number concentration of size-resolved PMs were monitored in Fukuoka, Japan by good time-resolved methods during the springtime. The highest monthly average $PM_{2.5}$ sulfate was found in May ($8.85{\mu}g\;m^{-3}$), followed by April ($8.36{\mu}g\;m^{-3}$), March ($8.13{\mu}g\;m^{-3}$), and June ($7.22{\mu}g\;m^{-3}$). The cases exceed the Japanese central government's safety standard for $PM_{2.5}$ ($35{\mu}g\;m^{-3}$) reached 10.11% during four months campaign. The fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ varied from 12.05% to 68.11% with average value of 35.49% throughout the entire period of monitoring. This high proportion of sulfate in $PM_{2.5}$ is an obvious characteristic of the ambient $PM_{2.5}$ in Fukuoka during the springtime. However, the average fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ in three rain events occurred during our intensive campaign fell right down to 15.53%. Unusually high $PM_{2.5}$ sulfate (> $30{\mu}g\;m^{-3}$) marked on three days were probably affected by the air parcels coming from the Chinese continent, the natural sulfur in the remote marine atmosphere, and a large number of ships sailing on the nearby sea. The theoretical number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ was originally calculated and then compared to $PM_{2.5}$ sulfate. A close resemblance between the diurnal variations of the theoretically calculated number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ and $PM_{2.5}$ sulfate concentration indicates that the secondary formed $(NH_4)_2SO_4$ was the primary form of sulfate in $PM_{2.5}$ during our monitoring period.

연속강우시 산성우의 이온농도 변화에 관한 조사연구 (A Study on Ion Concentration Change of Acid Rain by the Succeeding Raintall)

  • 박경렬;김대선
    • 한국환경보건학회지
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    • 제16권2호
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    • pp.11-20
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    • 1990
  • To investigate ionic characteristics of acid rain by the succeeding rainfall. bulk precipitation was collected every each 5mm rainfall from march to october 1990 at Dae Jeon area. pH, sulfate nitrate, chloride, ammonium ion was measured and analyzed. The result was as follows: 1. The weighted average pH of rain was 5.1$\pm$ 0.72(4.15~7.6) and rain pH less than 5.5 was appeared 51.3% 2. Average ion concentrations of sulfate, nitrate, chloride and ammonium ion was 125.12 $\mu$eq/l, 62.38 $\mu$eq/l, 31.95 $\mu$eq/l, 66.6 $\mu$eq/l and rates of each anions was 57%, 28.4%, 14.6% and rate of sulfate by nitrate was 2 times. 3. There is no correlations time interval of rainfall and Ion concentration change. 4. From initial to 15mm rainfall, each ion concentrations were decreased. and average concentration of pH, SO$^{-2}_{4}$, Cl ion concentration was increased in the succeeding rainfall 5. Only sulfate ion was correlated by the simple regression analysis with pH except NO$^{-}_{3}$, Cl$^{-}$ and NH$_{4}^{+}$ Cl$^{-}$ correlation coefficient was very high at the multiple regression analysis with pH. 6. Simple & multiple correlation coefficient among anions and NH$^{+}_{4}$ was very high especially N$^{+}_{4}$ and SO$^{2-}_{4}$ at simple regression analysis and SO$^{-2}_{4}$ and NO$_{3}^{-}$, Cl$^{-}$, NH$_{4}^{-}$ at multiple regression analysis.

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황산바륨의 최적합성조건 (Optimal Synthesis Conditions of Barium Sulfate)

  • 신화우;최광식
    • 약학회지
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    • 제46권5호
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    • pp.364-368
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    • 2002
  • Optimal synthetic conditions of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by Box and Wilson. Barium chloride and Sodium sulfate were utilized as reactants in order to prepare barium sulfate in this study. The optimum Synthesis conditions of barium sulfate obtained from this study are as follows; Reactant temperature; 60~75$^{\circ}C$ (viewpoint of yield) and 60~71$^{\circ}C$ (viewpoint of bulkiness). Concentration of two reactants; 12.7~14.4% (viewpoint of yield) and 5~10.5% (viewpoint of bulkiness). Mole ratio of two reactants, [BaCl$_2$]/[Na$_2$SO$_4$]; 1.62~1.96 (viewpoint of yield) and 2.0 (viewpoint of bulkiness). Reacting time; 13~15 minutes (viewpoint of yield) and 12~14 minutes (viewpoint of bulkiness). Drying temperature of product; 86~10$0^{\circ}C$ (viewpoint of yield) and 6$0^{\circ}C$ (viewpoint of bulkiness).

과량의 $SO_3$가 존재할 때 $3CaO.SiO_2$의 생성 저하 메카니즘 (Mechanism of $3CaO.SiO_2$ Prevention in Presence of Excess $SO_3$)

  • 정해문;한기성;최상흘
    • 한국세라믹학회지
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    • 제30권7호
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    • pp.527-534
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    • 1993
  • The phenomena that excess sulfate hindred the C3S formation in the presence of clinker liquid phase were investigated. In the case of (NH4)2SO4, assuming SO3 atmospheric condition, sulfate stabilized C2S and was enriched at the surface of C2S grains, so C2S was prevented from being dissolved into clinker melt. CaSO4 showed the similar aspect with (NH4)2SO4, however, the prevention of C3S formation by CaSO4 took more influence that C2AS and C4A3 were formed below 100$0^{\circ}C$, and remained upto clinkering temperature, 145$0^{\circ}C$, thus these intermediate phases caught CaO which would participate the C3S formation.

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황산바륨의 합성조건과 유동학적 특성 (Synthetic Conditions and Rheological Characteristics of Barium Sulfate)

  • 신화우;김준희;최광식;장영수;이광표
    • 약학회지
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    • 제36권6호
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    • pp.538-547
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    • 1992
  • Optimal synthetic condition of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. Barium chloride and magnesium sulfate were utilized as reactants in order to prepare barium sulfate in this study. It was found that optimum temperature range of reactant solutions was $60{\sim}100^{\circ}C$ and the optimum concentration range of the reactant solutions was $10{\sim}17.3%$ and $10{\sim}20%$ respectively, on the viewpoint of yield and bulkiness. The optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum reacting time range was $15{\sim}20$ minutes. The optimum drying temperature range was $110{\sim}130^{\circ}C$ from the viewpoint of yield, but it was $90{\sim}110^{\circ}C$ on the basis of bulkiness. Apparent viscosity of barium sulfate suspensions dispersed in various concentrations of Na. CMC was measured by using Brookfield synchrolectric viscometer model LVT, the relative equation, log ${\eta}_{sp}=A+B.{\phi}$ was examined and the equation was found to agree fairly well. 1 w/v% Na. CMC aqueous solution and 0.1 volume fraction of $BaSO_4$ powder were optimum in the preparation of $BaSO_4$ suspension showing highest viscosity at infinite shearing.

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