Rare earth elements（REEs） and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimet...Rare earth elements（REEs） and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimetric method.The results showed that they were hydrogenous crusts with average ∑REE content of 2084.69 μg/g and the light REE（LREE）/heavy REE（HREE） ratio of 4.84.The shale-normalized REE patterns showed positive Ce anomalies.The total content of strictly trivalent REEs increased with water depth.The Ce content and LREE/HREE ratios in Fe-Mn crusts above 2000 m were lower than those below 2000 m.The change in REE with water depth could be explained by two processes：adsorptive scavenging by setting matters and behaviors of REE in seawater.However, the Ce abundance took no obvious correlation with water depth reflects the constant Ce flux.The Ce in crusts existed mainly as Ce（IV）, implying that the oxidative-enriching process was controlled by kinetic factors.展开更多
Transition metal catalysts M-N-C（M = Co,Fe,Mn） were synthesized by a template-free method by heating meso-tetraphenyl porphyrins（i.e.CoTPP,FeTPPCl,MnTPPCl） precursors.The catalysts were characterized by N2 adsorpt...Transition metal catalysts M-N-C（M = Co,Fe,Mn） were synthesized by a template-free method by heating meso-tetraphenyl porphyrins（i.e.CoTPP,FeTPPCl,MnTPPCl） precursors.The catalysts were characterized by N2 adsorption-desorption,thermogravimetry,high-resolution transmission electron microscopy,and Raman and X-ray photoelectron spectroscopy.The selective oxidation of ethylbenzene with molecular oxygen under a solvent-free condition was carried out to explore the catalytic performance of the M-N-Cs,which exhibited different catalytic performance.That was ascribed to the difference in M（Co,Fe,Mn） and different graphitization degree forming during the heating process,in which M（Co,Fe,Mn） might have different catalytic activity on the formation of the M-N-C catalyst.All the M-N-C composites had remarkable recyclability in the selective oxidation of ethylbenzene.展开更多
Cobalt（Ⅱ）ion can catalyze the decolorrization reaction of hydrogan peroxide and m-cresol purple in a pH=10.0 NH3-NH4Cl buffer solution.The kinetic condition was studied,and the apparent activation energy（E′a=51.2...Cobalt（Ⅱ）ion can catalyze the decolorrization reaction of hydrogan peroxide and m-cresol purple in a pH=10.0 NH3-NH4Cl buffer solution.The kinetic condition was studied,and the apparent activation energy（E′a=51.26 KJ/mol.）and apparent rate constant[k′=1.13×10-4(s-1)]were determined.The linear range is 4.0～40 μg/L,and the detection limit for cobalt（Ⅱ）is 6.0×10-10 g/mL.The method was applied to the direct determination of trace Co（Ⅱ）in VB12,Jasmine tea and groundwater samples.展开更多
基金supported by the National Natural Science Foundation of China(40704029 40376016)+1 种基金China International Science and Technology Cooperation Project (2006DFB21620)the Young People Marine Science Foundation of State Oceanic Administration (2005304)
文摘Rare earth elements（REEs） and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimetric method.The results showed that they were hydrogenous crusts with average ∑REE content of 2084.69 μg/g and the light REE（LREE）/heavy REE（HREE） ratio of 4.84.The shale-normalized REE patterns showed positive Ce anomalies.The total content of strictly trivalent REEs increased with water depth.The Ce content and LREE/HREE ratios in Fe-Mn crusts above 2000 m were lower than those below 2000 m.The change in REE with water depth could be explained by two processes：adsorptive scavenging by setting matters and behaviors of REE in seawater.However, the Ce abundance took no obvious correlation with water depth reflects the constant Ce flux.The Ce in crusts existed mainly as Ce（IV）, implying that the oxidative-enriching process was controlled by kinetic factors.
基金supported by the National Natural Science Foundation of China (21103045, 1210040, 1103312)State Key Laboratory of Heavy Oil at China University of Petroleum (SKCHOP201504)Key Laboratory of Mineralogy and Metallogeny of the Chinese Academy of Sciences at Guangzhou Institute of Geochemistry(KLMM20150103)~~
文摘Transition metal catalysts M-N-C（M = Co,Fe,Mn） were synthesized by a template-free method by heating meso-tetraphenyl porphyrins（i.e.CoTPP,FeTPPCl,MnTPPCl） precursors.The catalysts were characterized by N2 adsorption-desorption,thermogravimetry,high-resolution transmission electron microscopy,and Raman and X-ray photoelectron spectroscopy.The selective oxidation of ethylbenzene with molecular oxygen under a solvent-free condition was carried out to explore the catalytic performance of the M-N-Cs,which exhibited different catalytic performance.That was ascribed to the difference in M（Co,Fe,Mn） and different graphitization degree forming during the heating process,in which M（Co,Fe,Mn） might have different catalytic activity on the formation of the M-N-C catalyst.All the M-N-C composites had remarkable recyclability in the selective oxidation of ethylbenzene.
文摘Cobalt（Ⅱ）ion can catalyze the decolorrization reaction of hydrogan peroxide and m-cresol purple in a pH=10.0 NH3-NH4Cl buffer solution.The kinetic condition was studied,and the apparent activation energy（E′a=51.26 KJ/mol.）and apparent rate constant[k′=1.13×10-4(s-1)]were determined.The linear range is 4.0～40 μg/L,and the detection limit for cobalt（Ⅱ）is 6.0×10-10 g/mL.The method was applied to the direct determination of trace Co（Ⅱ）in VB12,Jasmine tea and groundwater samples.
