74 resultados para Fe3
Resumo:
Iron is an essential trace element for biological requirements of phytoplankton. Effects of iron on physiological and biochemical characteristics of Microcystis wesenbergii were conducted in this study. Results showed that 0.01 mu M [Fe3+] seriously inhibited growth and chlorophyll synthesis of M. wesenbergii, and induced temporary increase of ATPase activities, however, NR. ACP and ALP activities were restrained by iron limitation. Interestingly, iron addition on day 8 resulted in the gradual restoration of structures and functions of above enzymes and resisted a variety of stresses from iron limitation. M. wesenbergii in 10 mu M [Fe3+] treatment group grew normally. enzymes maintained normal levels, and residual phosphate contents in cultures first sharply decreased, then smoothly as M. wesenbergii has a characteristic of luxury consumption of phosphorus. Above parameters in 100 mu M [Fe3+] treatment group were almost same with those in 10 mu M [Fe3+] treatment group except for NR, ACP and ALP activities. In 100 mu M [Fe3+] treatment group, activities of ACP and ALP had temporary increase because phosphate and ferric iron could form insoluble compound - ferric phosphate (Fe3PO4) through adsorption effect. resulting in lack of bioavailable phosphate in culture media. The experiment suggested that too low or too high iron can affect obviously physiological and biochemical characteristics of M. wesenbergii.
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The effects of nutrients on the photosynthetic recovery of Nostoc flagelliforme during re-hydration were investigated in order to see if their addition was necessary. Net photosynthesis was negligible in distilled water without nutrient-enrichment. Addition of K+ resulted in significant enhancement of net photosynthesis, whereas other nutrients (Fe3+, Mg2+, Na+, NO3-, PO43-, Cl-) and trace-metals (A(5)) showed little effect. The recovered net photosynthetic activity increased with the increased K+, and reached the maximum at concentrations above 230 mu M. Desiccation and re-hydration did not affect the dependence of photosynthetic recovery on K+. It was concluded that dried field populations of N. flagelliforme require exogenous addition of potassium for photosynthetic recovery and that growth may be potassium-limited in nature.
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Structural and magnetic characteristics of Fe3-xSnxO4 (x < 0.3) nanoparticles synthesized using the precipitation exchange method have been investigated by X-ray diffraction, transmission electron microscope, Mossbauer spectra, X-ray photoelectron spectroscopy and magnetization measurement. The mean particle dimension decreases from 8 to 6 nm, the lattice parameters enlarge, the saturation magnetization decreases, as well as the magnetization and the coercive field increase, with increasing tin-content. The paramagnetic property of the specimens indicates that the replacement of Fe3+ by Sn4+ on the octahedral sites of Fe3O4 causes a progressive lowering of the Curie temperature and the Curie temperatures of the materials are all lower than that of crystallite tin-doped magnetite. This striking debasing is due to the lessening of the grain size. This is the smallest size reported thus far for paramagnetic tin-doped magnetite particles. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
La0.67Sr0.33MnO3La0.67Sr0.33Mn1-xFexO3Sr2xLaxMnMoO6Sr2xLaxMnWO6Sr2(NiCo)WO6 -La0.67Sr0.33MnO39001300 La0.67Sr0.33Mn1-xFexO3(0x0.2)Fe3La0.67Sr0.33MnO3x0.08La0.67Sr0.33Mn1-xFexO3(0x0.20)EPRHppTminTminx=0.20380KLa0.67Sr0.33MnO3 Sr2xLaxMnMoO6 (0x1)5TLa3+
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LDAGGA 5dTMB2 (TM = Hf, Ta, W, Re, Os and Ir, Pt)Pmmn6.87.2TM d-B pOsB2WReIr ReB2WB2ReB2WB2P63/mmcP6/mmmReB2WB2Poisson WIEN2k+Cs2AgF4Cs2AgF4Cs2AgF4 WIEN2k+YBaFe2O53dFe2+ Fe3+t2g0.73YBaFe2O5O 2pFe egFe2+ Fe3+dxzG
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Eu~3Sm~3Mn~2Fe~3Co~2Ni~2ZnOcccc10Onm15357-366nmEu3+Sm3Mn2+Fe3Co2Ni2Zn2+O2- Eu3+ZnO363nm368nmEg=3.423.40evEu3Zn1-xEux0.005x0.15Zn1-xTMxO356nm-369nm3.34-3.46eVCo2d-dZn1-xCoxO60Zn1-xEuxO90Zn1-xEuxO613nmEu37F5D378nmZnO394nmEu3+5D07FJJ1234zno378nmEu3+5D07F2znoE4-400KZn0.9Eu0.1OznogCooIO23oK200KM-HBr021emgHc327OeZn0.9Mn0.1OZn0.9Ni0.1OZn0.9Co0.1O80KZn0.9Eu0.1OZT110K14.53Zn1-xTMxOCoFeNiMnZn1-xTMxO80Co2DMSsol-gelZnoTMMCM-41AAOZnO:TMMCM-41MCM-41AAoloonmMCM-41Zn0.9Co0.1O80K-30OKMnFeNiZnoAAOZnO:TM(TM=MnFeCoNiSOK-30OKZnO:AABuSmcoZnlxCoxOPH5ZnORERE=EuSmZn0.98Co0.02O80KZnOREREEuSm80K
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ABBLaSr2Mn2O7CrTiNiFeMnBCr3Mn4Cr3crNi2Fe3MnLaS2Mn2O7MnMnMnFex0.2MR28OK74LasrZMn2O7Bi3+Sr2+x0.2Bi3Bi3TcoGdn=3Laca4kMn3O10La3-3xCa13xMn3O100.5x1.0La3x0.50.7x=0.8-1.0La3Mn3Mn3+Mn4+LaxCa4-xMn3O10x0-0.9Mn4x0.2x0.2xG-AFMx0.9C-AFM
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1758-3600m 6175826203200350035873600m22540185225 1.2251028452251010928 1604511745B1394873U/ml16SrDNAB1394Bacillus subtilis60pH 8.0 405060 Mn2+ Mg2+ Ca2+Hg2+ Fe3+ Cu2+ Zn2+ Fe2+PMSF 2.10040 Rhizoctonia solaniCandida albicans373537%35%1845%SHA6Fusarium oxysporum10SHA6, SHA6Aurantimonas altamirensis 3.205SHA4100g/ml83%,400ppm48h38%SHA4Nocardiopsis sp
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CIB871CIB87130(0.3%)IG(0.03%)(1%)60-6550%-70%PH7.037,5mMAg+Co2+Hg2+, Mg2+, Zn2+ Fe2+Fe3+
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CNO13% X-() (Thiobacillus Beijerinek)(Thiobacillu ferrooxidans, TF), (Thiobacillus thiooxidans, TT)TT (15-20)20g/L60% 48.5h91.2281.6hPH (1) Arrhenius(2) PHPHPH (3) 30g/L(4) TT10g/L25-36 100% Fe2+Fe3+Fe3+ Cr3+Cr6+,Cr6+CrO3This paper has studied bioleaching and recovery of Chronium(Cr)from electroplating sludge by two consortum of bacteria and their combination, with sludge produced by microbiological process treating electroplating wastewater containing Cr as material. The share of Cr is 13% and its state is Cr (OH)3 in the sludge. One of the bacteria in the paper was isolated from acid sewage sludge and the other was from acid mineral water. The former was tested and determined as Thiobacillus ferroxidans(TF) and the latter was Thiobacillus thiooxidans(TT). Different microorganisms, responsible for the metal leaching activity, have great influence on the efficiency of leaching. The results showed that TT has biggest power. Experiments were conducted to examined effects of three different ways of leaching(Shaking, Down-leaching, Static-leaching). When temperature was in-door's (15-20)and concentration of the sludge was 20g/L, the bioleaching time required to reach 60% of Cr solubilization with the above three ways were 91.2, 48.5, 81.6h respectively. Down-leaching was proved to be the most efficient. The influence of different temperature, initial PH, concentration of the sludge and non-mature inoculum had been studied. The results obtained reveal that: (1) The variation of temperature is important during the time from initial to middle of leaching. The reaction of bioleaching belongs to first-order. The relation between the bioleaching rate constant(In k)and temerature can be expressed by Arrhenius function. (2) The fittest initial PH is the nature PH of mature inoculum. Any alteration with it could cause clearly negative effection. (3) The concentration of the sludge can make strong influence on the bioleaching efficiency. But when the concentration is above 30g/L, the increasing of Cr in the solution is little. (4) If non-mature inoculum acts as the bioleachin microorganism, little quantity of Cr would be gained from the sludge. But the micormass in the solution is very active. The results from electron microscope showed that microorganisms adhered to the surface of the sludge and the adherence was the first stage of the bioleaching. Some salts of Cr can be obtained afer the water of the bioleaching solution being evaporated. By analysing the results of experiment with X-Ray spectroscopy, the salt was identified as CrO3. The recovery rate of Cr is 78.4%.
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,Vc .pH 7.0 ,35 2 4h,2 L . ,L .pH/ , ,pH/ 8 40 ,Fe3+ ,Co2 + ,2 ,6 , ,TritonX 10 0Tween 80 . 8 7
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Two organically templated trivalent metal-containing crystalline zirconium phosphate materials FeZrPO-8 and AlZrPO-8 have been prepared hydrothermally by using fluoride as a mineralizer, and 1,6-diaminohexane (DAH) as templates. The powder XRD patterns indicate that the as-synthesized products are new materials. Substitutions of Al3+ or Fe3+ into Zr4+ sites were confirmed by a combination of powder X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) studies. The thermal behavior of the title compounds have been investigated using TG-DTA and X-ray thermodiffractometry, which indicated that the inorganic framework of the compounds are thermally stable up to similar to400 degreesC. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) seawaters. A study of inorganic carbon (IC) forms and its influencing factors was presented in Liaodong Gulf sediments, and especially the influence of iron was discussed in detail. Inorganic carbon in Liaodong Gulf sediments was divided into five forms: NaCl, NH3H2O, NaOH, NH2OHHCl and HCl. The concentration of NaCl and NaOH forms were similar and they only occupied the minority of total inorganic carbon (TIC). However, NH3H2O, NH2OHHCl and HCl forms were the principal forms of TIC and accounted for more than 80% of TIC. Especially, the percentage of NH3H2O form was much higher than that in the Changjiang River Estuary and Jiaozhou Bay sediments. All forms of inorganic carbon were influenced by organic carbon,pore water, iron, pH, redox potential(Eh) and sulfur potential(Es) in sediments, moreover, the influences had different characteristics for different IC forms. However, the redox reactions of iron affected mainly active IC forms. Iron had little effect on NH2OHHCl and HCl forms of IC which were influenced mainly by pH. Iron had a stronger influence on NaCl, NaOH and NH3H2O forms of IC; the influence of Fe2+ was higher than Fe3+ and its effect on NH3H2O form was stronger than on NaCl and NaOH forms.
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3 200~3 600 m185,1B1394,873 U/mL16S rDNA,(Bacillus subtilis):60,pH 8.0,3040,40~60,;Mn2+Mg2+Ca2+,Hg2+Fe3+Cu2+Zn2+Fe2+;PMSF,
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First principles calculations using the augmented plane wave plus local orbitals method, as implemented in the WIEN2k code, have been used to investigate the electronic and magnetic properties of YBaFe2O5, especially as regards the charge-orbital ordering. Although the total 3d charge disproportion is rather small, an orbital order parameter defined as the difference between t(2g) orbital occupations of Fe2+ and Fe3+ cations is large (0,73) and gives unambiguous evidence for charge and orbital ordering: Strong hybridization between O 2p and Fe e(g) states results in the nearly complete loss of the separation between the total charges at the Fe2+ and Fe3+ atoms.
