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Characterization of apparent sulfur oxidation activity of thermophilic archaea in bioleaching of chalcopyrite 被引量:5
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作者 朱薇 夏金兰 +2 位作者 彭安安 聂珍媛 邱冠周 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第8期2383-2388,共6页
The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi (JCM 8954), Metallosphaera sedula (YN 23), Acidianus manzaensis (YN 25) and Sulfolobus metallicus (YN 24) and the... The apparent sulfur oxidation activities of four pure thermophilic archaea, Acidianus brierleyi (JCM 8954), Metallosphaera sedula (YN 23), Acidianus manzaensis (YN 25) and Sulfolobus metallicus (YN 24) and their mixture in bioleaching chalcopyrite were compared, which were characterized indirectly by the evolution of the cells concentration, pH value and sulfate ions concentration in solution. The results show that the mixed culture contributed significantly to the raising of leaching rate, which suggests that the mixed culture had a higher sulfur oxidation activity than the pure culture. Meanwhile, the results also indicate that the changes of parameters characterizing the sulfur oxidation activity of thermophilic archaea are often influenced by many factors, so it is hard to reflect accurately the specific sulfur oxidation activities among the different sulfur-oxidizing microbes when bioleaching chalcopyrite at different conditions. Accordingly, an efficient method to characterize microbial sulfur oxidation activity appears to be desirable. 展开更多
关键词 thermophilic archaea sulfur oxidation activity CHARACTERIZATION BIOLEACHING
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Bacterial oxidation activity in heap leaching 被引量:1
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作者 柳建设 夏海波 +1 位作者 王兆慧 胡岳华 《Journal of Central South University of Technology》 EI 2004年第4期375-379,共5页
Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans(T.f.) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The s... Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans(T.f.) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The surveys of production process and the bacterial oxidation activity in the heap bioleaching were investigated. The results show that pH value is high, bacteria biomass and ferric concentration are low, generation time (above 7.13 h) is long in leachate, and less bacteria are adsorbed on the ores. The bacteria in the leachate exposing on the surface and connecting with mineral, have much faster oxidation rate of Fe(Ⅱ) and shorter generation time, compared with those which are in the reservoir for a long time. There is diversity for oxidation activity of Fe(Ⅱ), while there is no diversity for oxidation of sulfur. So it is advisable to add sulfuric acid to degrade pH value to 2.0, add nutrients and shorten recycling time of leachate, so as to enhance bacteria concentration of leachate and the leaching efficiency. 展开更多
关键词 heap bioleaching oxidation activity BACTERIA
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SnO_2 nano-sheet as an efficient catalyst for CO oxidation 被引量:2
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作者 彭洪根 彭跃 +4 位作者 徐香兰 方修忠 刘玥 蔡建信 王翔 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期2004-2010,共7页
Polycrystalline SnO2 fine powder consisting of nano-particles (SnO2-NP), SnO2 nano-sheets (SnO2-NS), and SnO2 containing both nano-rods and nano-particles (SnO2-NR+NP) were prepared and used for CO oxidation. S... Polycrystalline SnO2 fine powder consisting of nano-particles (SnO2-NP), SnO2 nano-sheets (SnO2-NS), and SnO2 containing both nano-rods and nano-particles (SnO2-NR+NP) were prepared and used for CO oxidation. SnO2-NS possesses a mesoporous structure and has a higher surface area, larger pore volume, and more active species than SnO2-NP, and shows improved activity. In contrast, although SnO2-NR+NP has only a slightly higher surface area and pore volume, and slightly more active surface oxygen species than SnO2-NP, it has more exposed active (110) facets, which is the reason for its improved oxidation activity. Water vapor has only a reversible and weak influence on SnO2-NS, therefore it is a potential catalyst for emission control processes. 展开更多
关键词 SnO2 catalyst Nano-sheet Nano-rod Exposed active facet EO oxidation
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Electrochemically reduced graphene oxide with enhanced electrocatalytic activity toward tetracycline detection 被引量:4
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作者 胥燕燕 高明明 +4 位作者 张国辉 王新华 李佳佳 王曙光 桑元华 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期1936-1942,共7页
An electrochemically reduced graphene oxide sample, ERGO_0.8v, was prepared by electrochemical reduction of graphene oxide (GO) at -0.8 V, which shows unique electrocatalytic activity toward tetracycline (TTC) det... An electrochemically reduced graphene oxide sample, ERGO_0.8v, was prepared by electrochemical reduction of graphene oxide (GO) at -0.8 V, which shows unique electrocatalytic activity toward tetracycline (TTC) detection compared to the ERGO-12v (GO applied to a negative potential of-1.2 V), GO, chemically reduced GO (CRGO)-modified glassy carbon electrode (GC) and bare GC electrodes. The redox peaks of TTC on an ERGO-0.8v-modifled glass carbon electrode (GC/ERGO-0.8v) were within 0-0.5 V in a pH 3.0 buffer solution with the oxidation peak current correlating well with TTC concentration over a wide range from 0.1 to 160 mg/L Physical characterizations with Fourier transform infrared (FT-IR), Raman, and X-ray photoelectron spectroscopies (XPS) demonstrated that the oxygen-containing functional groups on GO diminished after the electrochemical reduction at -0.8 V, yet still existed in large amounts, and the defect density changed as new sp2 domains were formed. These changes demonstrated that this adjustment in the number of oxygen-containing groups might be the main factor affecting the electrocatalytic behavior of ERGO. Additionally, the defect density and sp2 domains also exert a profound influence on this behavior. A possible mechanism for the TTC redox reaction at the GC/ERGO-0.8v electrode is also presented. This work suggests that the electrochemical reduction is an effective method to establish new catalytic activities of GO by setting appropriate parameters. 展开更多
关键词 Electrochemically reduced graphene oxide Electrochemical detection Tetracycline Electrocatalytic activity Oxygen-containing functional groups
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An examination of active sites on Au-Ag bimetallic catalysts based on CO oxidation over Au/Ag_2O and a comparison to Ag-contaminated Au powder
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作者 Yasuo Iizuka Yasuhiro Hiragi +1 位作者 Hikaru Yakushiji Takumi Miura 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第10期1712-1720,共9页
There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact inter... There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact interfaces between AgOx regions and the surface of the bulk Au as active working sites, while the other holds that charge transfer from Ag to Au in a surface Au‐Ag alloy causes the catalytic activity. One key point in examining these theories and determining the origin of the synergy in‐volves determining whether or not Ag exists as an oxide or as a metallic alloy on the Au surface. To confirm that enhanced activity results from contact between Ag2O and Au nanoparticles (NPs), a comparative study of catalytic CO oxidation over Au/Ag2O and Ag2O was performed in the present work, using a closed recirculation reaction system. A reaction mixture consisting of a stoichiometric composition of CO and O2 (CO/O2=2/1) was supplied to both catalysts and the resulting pressure decrease rates were tracked, from which the amounts of gas consumed as well as the quantity of CO2 produced were determined. The steady state reactions of both Au/Ag2O and Ag2O did not lead to any meaningful difference in the rate of pressure decrease during the oxidation. The pressure decrease over both catalysts was attributed to the reduction of surface lattice O on Ag2O by CO. The results obtained for Au/Ag2O are in good agreement with previous data resulting from the use of Ag‐contaminated Au powder (Ag/Au‐b) having an oxidized surfaces. This finding suggests that the perimeters between AgOx zones and the bulk Au surface may not function as active sites during CO oxidation. A review of previous results obtained with Ag/Au‐b specimens having so‐called steady state surfaces indicates that AgOx species in such materials are reduced to the 0 state to form a Ag‐Au alloy that provides the active sites. 展开更多
关键词 Gold-silver bimetallic catalyst Synergy effect Carbon monoxide oxidation Active site Gold-silver alloy
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Intensification of bituminous coal and lignite oxidation by copper-based activating additives
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作者 K.B.Larionov I.V.Mishakov +1 位作者 K.V.Slyusarskiy A.A.Vedyagin 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第1期141-153,共13页
The oxidation of lignite and bituminous coal samples modified by 5 wt%(in terms of dry salt)addition of copper salts Cu(NO_(3))_(2),CuSO_(4),and Cu(CH_(3)COO)_(2) was studied.The samples’reactivity was studied by the... The oxidation of lignite and bituminous coal samples modified by 5 wt%(in terms of dry salt)addition of copper salts Cu(NO_(3))_(2),CuSO_(4),and Cu(CH_(3)COO)_(2) was studied.The samples’reactivity was studied by thermogravimetry within a temperature range of 45–600℃ at a heating rate of 2.5℃/min in an oxidizing environment.The introduction of activating additives has resulted in a significant decrease in the temperature of intense oxidation onset(ΔT_(i)=20/94℃),in a reduction in the sample residence time in the volatile matter release region(Δt_(e)=2/22 min)and the total duration of the coal combustible mass oxidation(Δt_(f)=8/14 min).The Friedman method was used to calculate the activation energy values for the oxidation process of the modified samples.The maximum change in activation energy values was observed for the bituminous coal sample.The possible mechanism behind the action of the copper-salt additives,which activate the oxidation of lignite and bituminous coal,is discussed.According to the data of mass spectrometric analysis,the concentration of NOx in the reaction products decreases as the temperature of the activated oxidation process is shifted towards the low-temperature region. 展开更多
关键词 Coal Activated oxidation Copper nitrate Copper sulfate Copper acetate Thermo-gravimetric and mass spectrometry analysis
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Electron Donating Property and Catalytic Activity ofPerovskite-type Mixed Oxides (ABO_3) Consisting of Rare Earth and 3d Transition Metals
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作者 S.Sugunant and V.Meera(Dept. of Applied Chemistry, Cochin University of Science and Technology, Kochi-682022, India) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第3期229-231,共3页
The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have... The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides 展开更多
关键词 activity type ABO3 Consisting of Rare Earth and 3d Transition Metals Electron Donating Property and Catalytic activity ofPerovskite-type Mixed Oxides
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Invariance and Noises of Shannon Entropy for Information on Oxidative Activity of DNA in All Living Cells for Medical Diagnostics
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作者 Nikolay E. Galich 《American Journal of Operations Research》 2014年第2期72-89,共18页
We analyze oxidative activity of DNA due to fluorescence of chromosomes inside cells, using flow cytometry method with nanometer spatial resolution. Statistics of fluorescence is presented in histogram as frequency di... We analyze oxidative activity of DNA due to fluorescence of chromosomes inside cells, using flow cytometry method with nanometer spatial resolution. Statistics of fluorescence is presented in histogram as frequency distributions of flashes in the dependence on their intensity and in distributions of Shannon entropy, which was defined on the base of normalized distribution of information in original histogram for frequency of flashes. We show that overall sum of entropy, i.e. total entropy E , for any histogram is invariant and has identical trends of changes all values of E(r) = lnr at reduction of histogram’ rank r. This invariance reflects informational homeostasis of chromosomes activity in multi-scale networks of entropy inside all cells in various samples of blood for DNA inside neutrophils, lymphocytes, inside all leukocytes of human and inside chicken erythrocytes for various dyes, colors and various excitations of fluorescence. Informational homeostasis of oxidative activity of 3D DNA in the full set of chromosomes inside living cells exists for any Shannon-Weaver index of biodiversity of cells, at any state of health different beings. Regulation perturbations in information activity DNA provides informational adaptability and vitality of cells at homeostasis support. Noises of entropy, during regulation of informational homeostasis, depend on the states of health in real time. The main structural reconstructions of chromosomal correlations, corresponding to self-regulation of homeostasis, occur in the most large-scale networks of entropy, for rank r<32. We show that stability of homeostasis is supported by activity of all 46 chromosomes inside cells. Patterns, hidden switching and branching in sequences of averages of H?lder and central moments for noises in regulation of homeostasis define new opportunities in diagnostics of health and immunity. All people and all aerobic beings have one overall homeostatic level for countdown of information activity of DNA inside cells. We noted very bad and dangerous properties of artificial cells with other levels of informational homeostasis for all aerobic beings in foods, medical treatment and in biotechnologies. 展开更多
关键词 Averages of Holder for Noises of Shannon Entropy in Homeostasis Regulation of Total Shannon Entropy Entropy and Information of DNA activity in Cells Information Entropy for Oxidizing activity of DNA Informational Homeostasis and Self-Regulation of DNA activity in Cells Noise of Information Entropy
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Analysis of CO_3O_4/ Mildly Oxidized Graphite Oxide(mGO)Nanocomposites of Mild Oxidation Degree for the Removal of Acid Orange 7
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作者 王倩 时鹏辉 +3 位作者 朱少波 李洁冰 ASIF Hussain 李登新 《Journal of Donghua University(English Edition)》 EI CAS 2015年第2期185-191,共7页
In this study,a series of Co_3O_4/ mildly oxidized graphite oxide(mGO) nanocatalysts(Co_3O_4/ mGO-l,Co_3O_4/ mGO-2 and Co_3O_4/mGO-3) were synthesized through solvothermal method and used as a mediator for the heterog... In this study,a series of Co_3O_4/ mildly oxidized graphite oxide(mGO) nanocatalysts(Co_3O_4/ mGO-l,Co_3O_4/ mGO-2 and Co_3O_4/mGO-3) were synthesized through solvothermal method and used as a mediator for the heterogeneous peroxymonosulfate(PMS)activation.The performance of CO_3O_4 / mGO/PMS system was investigated using acid orange 7(AO7).Results showed that Co_3O_4/mGO-3 had the best degradation efficiency of AO7 and the removal rate was above 90%in about 6 min.The phenomenon indicated the catalytic activity of Co_3O_4/mGO composites was related to the oxidation degree of graphite oxide(GO).In addition,experiments showed the content of Co_3O_4 had an effect on the catalytic activity.The composites were characterized with X-ray powder diffraction(XRD),FTIR,Raman,X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM).According to the charactrization and synergistic catalytic mechanism,the generation of Co—OH complexes found to be the initial step to activate PMS in the heterogeneous system of Co_3O_4/mGO hybrid. 展开更多
关键词 graphite photoelectron orange oxidized Orange synergistic dispersed attributed activate heterogeneous
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Effect of CeO_2 on Crystal Structures and Catalytic Properties of the Mn_2O_3 Catalysts
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作者 罗孟飞 朱波 袁贤鑫 《Journal of Rare Earths》 SCIE EI CAS CSCD 1994年第4期259-263,共5页
The manganese-cerium complex oxide catalysts were prepared by coprecipitation.The crystal structures,the desorption properties of surface oxygen and reducibility of these catalysts were investigated by means of X-ray ... The manganese-cerium complex oxide catalysts were prepared by coprecipitation.The crystal structures,the desorption properties of surface oxygen and reducibility of these catalysts were investigated by means of X-ray diffraction analysis (XRD),temperature-programmed desopotion-mass spectrography (TPD-MS) and temperature-programmed reduction (TPR).The crystal structure of Mn-O and Mn-Ce-O catalysts are bixbyite-Mn2O3 and γ-Mn2O3 respectively.The presence of CeO2 can not change the position of the feature peaks of Mn2O3 on the TPD or profiles,but can increase evidently the amount of the adsorbed surface oxygen,which are correlated with the catalytic activity for methanol oxidation.The activity of the catalyst is optimum when Mn/Ce atom ratio is 4:1.The presence of CeO2 brings a change of the reducibility,which reveals that there is an interaction between Mn2O3 and CeO2. 展开更多
关键词 Mn_2O_3 CeO_2 Surface oxygen oxidation activity Crystal structure
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Effect of Addition of Sm_2O_3 on Property of CuO-γ-Al_2O_3 Catalyst
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作者 蒋晓原 周仁贤 +1 位作者 毛建新 郑小明 《Journal of Rare Earths》 SCIE EI CAS CSCD 1997年第3期20-26,共7页
Effect of the addition of Sm 2O 3 on CuO γ Al 2O 3 catalyst for CO oxidation reaction was investigated. The result shows that the right amount of Sm 2O 3 can promote the adsorption of the surface oxygen a... Effect of the addition of Sm 2O 3 on CuO γ Al 2O 3 catalyst for CO oxidation reaction was investigated. The result shows that the right amount of Sm 2O 3 can promote the adsorption of the surface oxygen and recovery of CuO γ Al 2O 3 catalyst. Sm 2O 3 plays an important role in change of γ Al 2O 3 phase into θ Al 2O 3 phase. In addition, the right amount of Sm 2O 3(5%) can improve the oxidation activity of the CuO γ Al 2O 3 catalyst. Whereas an excess of Sm 2O 3(10%) makes the CuO crystal in CuO γ Al 2O 3 catalyst become bigger and restrain the oxidation activity of the CuO γ Al 2O 3 catalyst. 展开更多
关键词 Rare earths CuO γ Al 2O 3 catalyst Sm 2O 3 oxidation activity
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A binder-free, flexible cathode for rechargeable Na-O_2 batteries 被引量:1
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作者 李娜 徐丹 +2 位作者 鲍迪 马金玲 张新波 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第7期1172-1179,共8页
Rechargeable Na-O2 batteries have attracted significant attention as energy storage devices owing to their theoretically high energy storage capacity and the natural abundance of sodium. However, practical application... Rechargeable Na-O2 batteries have attracted significant attention as energy storage devices owing to their theoretically high energy storage capacity and the natural abundance of sodium. However, practical applications of this type of battery still suffer from low specific capability, poor cycle sta- bility, instable electrolytes, and unstable polymer binders. Herein, we report a facile method of synthesizing binder free and flexible cathodes with C0304 nanowire arrays vertically grown onto carbon textiles. When employed as a cathode for Na-O2 batteries, this cathode exhibits superior performance, including a reduction of charge overpotential, high specific capacity (4687 mAh/g), and cycle stability up to 62 cycles. These enhanced performance can be attributed to the synergistic effect of the porosity and catalytic activity of the C0304 nanowire catalyst. 展开更多
关键词 FlexibleBinder-freeCobalt oxide nanowiresPorosityCatalytic activity
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Enhanced cycle performance of Li/S battery with the reduced graphene oxide/activated carbon functional interlayer 被引量:8
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作者 Haipeng Li Liancheng Sun +3 位作者 Yongguang Zhang Taizhe Tan Gongkai Wang Zhumabay Bakenov 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第6期1276-1281,共6页
The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great co... The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries. 展开更多
关键词 Lithium/sulfur battery Shuttle effect Functional interlayer Reduced graphene oxide/activated carbon composite
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Catalytic Performance of Carbon Materials Supported Pd Nanoparticles in Selective Hydrogenation of Acetylene 被引量:2
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作者 姚繁繁 霍羽佳 马运生 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第5期559-565,I0002,共8页
Pd/C catalysts were prepared by deposited Pd nanoparticles (NPs) on different carbon supports including activated carbon (AC), graphite oxide (GO), and reduced graphite oxide (rGO) using sol-immobilization met... Pd/C catalysts were prepared by deposited Pd nanoparticles (NPs) on different carbon supports including activated carbon (AC), graphite oxide (GO), and reduced graphite oxide (rGO) using sol-immobilization method. Through transmission electron microscopy, powder X-ray di raction, and X-ray photoelectron spectroscopy, the role of the carbon supports for the catalytic performances of Pd/C catalysts was examined in selective hydrogenation of acetylene. The results indicate that Pd/AC exhibited higher activity and selectivity than Pd/GO and Pd/rGO in the gas phase selective hydrogenation of acetylene. Thermal and chemical treatment of AC supports also have some effect on the catalytic performance of Pd/AC catalysts. The differences in the activity and selectivity of various Pd/C catalysts were partly attributed to the metal-support interaction. 展开更多
关键词 Selective hydrogenation of acetylene Pd Active carbon Graphite oxide Reduced graphite oxide X-ray photoelectron spectroscopy
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Immobilized reactor for rapid destruction of recalcitrant organics and inorganics in tannery wastewater 被引量:4
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作者 A.Ganesh Kumar G.Sekaran +1 位作者 S.Swarnalatha B.Prasad Rao 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第4期681-685,共5页
The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic acti... The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic activated carbon oxidation(CAACO) reactor, an immobilized cell reactor using chemoautotrophs for the treatment of tannery wastewater. The treatment scheme comprised of anaerobic treatment, sand filtration, and CAACO reactor, which remove COD, BOD, TOC, VFA and sulphides respectively by 86%, 95%, 81%, 71% and 100%. Rice bran mesoporous activated carbon prepared indigenously and was used for immobilization of chemoautotrophs. The degradation of xenobiotic compounds by CAACO was confirmed through HPLC and FT-IR techniques. 展开更多
关键词 chemo-autotrophic activated carbon oxidation(CAACO) mesoporous rice bran activated carbon XENOBIOTIC
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Relationship Between Iron Oxides and Surface Charge Characteristics in Soils 被引量:2
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作者 SHAOZONG-CHEN WANGWEI-JUN 《Pedosphere》 SCIE CAS CSCD 1991年第1期29-39,共11页
The relationship between iron oxides and surface charge characteristics in variable charge soils ( latosol and red earth ) was studied in following three ways. ( 1 ) Remove free iron oxides ( Fed ) and amorphous iron ... The relationship between iron oxides and surface charge characteristics in variable charge soils ( latosol and red earth ) was studied in following three ways. ( 1 ) Remove free iron oxides ( Fed ) and amorphous iron oxides ( Feo ) from the soils with sodium dithionite and acid ammonium oxalate solution respectively. ( 2 ) Add 2% glucose ( on the basis of air-dry soil weight ) to soils and incubate under submerged condition to activate iron oxides, and then the mixtures are dehydrated and air-dried to age iron oxides. ( 3 ) Precipitate various crystalline forms of iron oxides onto kaolinite. The results showed that free iron oxides ( Fed ) were the chief carrier of variable positive charges. Of which crystalline iron oxides ( Fed-Feo ) presented mainly as discrete particles in the soils and could only play a role of the carrier of positive charges, and did little influence on negative charges. Whereas the amorphous iron oxides ( Feo ) , which presented mainly as a coating with a large specific surface area, not only had positive charges, but also blocked the negative charge sites in soils. Submerged incubation activated iron oxides in the soils, and increased the amount of amorphous iron oxides and the degree of activation of iron oxide, which resulted in the increase of positive and negative charges of soils. Dehydration and air-dry aged iron oxides in soils and decreased the amount of amorphous iron oxides and the degree of activation of iron oxide, and also led to the decrease of positive and negative charges. Both the submerged incubation and the dehydration and air-dry had no significant influence on net charges. Precipitation of iron oxides onto kaolinite markedly increased positive charges and decreased negative charges. Amorphous iron oxide having a larger surface area contributed more positive charge sites and blocked more negative charge sites in kaolinite than crystalline goethite. 展开更多
关键词 amorphous iron oxide degree of activation of iron oxide free iron oxide surface charge variable charge soil
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Effects of selenium and sulfur on antioxidants and physiological parameters of garlic plants during senescence 被引量:3
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作者 CHENG Bo LIAN Hai-feng +5 位作者 LIU Ying-ying YU Xin-hui SUN Ya-li SUN Xiu-dong SHI Qing-hua LIU Shi-qi 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第3期566-572,共7页
A hydroponic study was conducted to determine the effects of selenium(Se: 0, 3, 6 μmol L^-1) on senescence-related oxidative stress in garlic plants grown under two sulfur(S) levels. We evaluated the yields of p... A hydroponic study was conducted to determine the effects of selenium(Se: 0, 3, 6 μmol L^-1) on senescence-related oxidative stress in garlic plants grown under two sulfur(S) levels. We evaluated the yields of plants harvested at 160 and 200 days after sowing. Plants grown under a low Se dose(0.3 μmol L^-1) at low S level showed higher yields(12.0% increase in fresh weight yield, 13.7% increase in dry weight yield) than the controls, despite a decrease in chlorophyll concentration. Compared with control plants, the Se-treated plants showed lower levels of lipid peroxidation. The Se-treated plants also showed higher activities of glut athione peroxidase and catalase, but lower superoxide dismutase activities. Changes in Fv/Fm values and proline contents were affected more strongly by S than by Se. On the basis of our results, we can conclude that Se plays a key role in the antioxidant systems in garlic seedlings. It delays senescence by alleviating the peroxide stress, but it can be toxic at high levels. A high S level may increase tolerance to high Se concentrations through reducing Se accumulation in plants. 展开更多
关键词 selenium sulfur garlic antioxidant activity oxidative stress senescence
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Self-reaction of initial active groups in coal 被引量:7
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作者 Qi Xuyao Wang Deming +1 位作者 James A Milke Zhong Xiaoxing 《International Journal of Mining Science and Technology》 2012年第2期169-175,共7页
For further understanding of self-heating of coal, we tested the reactions of seven different ranks of coal under inert atmosphere. In the test, 50-gram of coal sample ranged from 0.18 mm to 0.38 mm was put into a spe... For further understanding of self-heating of coal, we tested the reactions of seven different ranks of coal under inert atmosphere. In the test, 50-gram of coal sample ranged from 0.18 mm to 0.38 mm was put into a special designed copper reaction vessel and let pure nitrogen to flow into the coal sample from the bottom at a rate of 100 mL/min. The programmed temperature enclosure was run at a programmed rate of 0.8 ~C/min. The concentration of the carbon oxides and the coal temperature were tested. The results show that the coal reactions under inert atmosphere can generate CO and C02. The reactions under inert atmosphere are affected by coal ranks, initial pore structure of coal and sulfur content. For low ranks of coal, the productions of carbon oxides are piecewise. The coal temperature is lower than the surrounding temperature throughout the reactions under inert atmosphere, but it rises quickly and reaches a crossing point temperature in the later stage under dry-air atmosphere. Based on the analysis, it indicates the self-reaction of initial active groups exists in the self-heating of coal besides the reactions in the two parallel reactions model. Spontaneous combustion of coal is due to both the oxidation heat accumulation and the chain reaction. A new reaction model of self-heating of coal was orooosed. 展开更多
关键词 CoalSelf-heatingInitial active groupsSelf-reactionInert atmosphereCarbon oxides
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Reduction of chromium oxides in stainless steel dust 被引量:1
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作者 Yan-ling Zhang Wen-ming Guo Xin-lei Jia 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第6期573-581,共9页
The recovery of metal oxides from stainless steel dust using C(graphite), SiFe, and Al as reductants was investigated under various conditions. The apparent distribution ratio of Cr(L Cr ′^m/s ) in the recovered ... The recovery of metal oxides from stainless steel dust using C(graphite), SiFe, and Al as reductants was investigated under various conditions. The apparent distribution ratio of Cr(L Cr ′^m/s ) in the recovered metal and residual slag phases was defined as the major performance metric. The results show that the recovery ratio of metals increases as the ratio of CaO :SiO2 by mass in the residual slag increases to 1.17. The residual content of metals in the slag decreases as the Al2O3 content of the slag is increased from approximately 8wt% to 10wt%. The recovery ratio of Cr increases with increasing L Cr ′^ m/s , and a linear relationship between L Cr ′^m/s and the activity coefficient ratio of CrO in the slag and the recovered metal phase is observed. The combination of C and SiFe or Al as the reducing agents reveals that Si is the more effective coreductant. 展开更多
关键词 stainless steel dust chromium oxides recovery apparent distribution ratio activity coefficient
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MIL-101(Cr)-decorated Ti/TiO_(2) anode for electrochemical oxidation of aromatic pollutants from water 被引量:2
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作者 Zepeng Zhang Yunyun Li +4 位作者 Longzhang Dong Zhonglong Yin Ziqi Tian Weiben Yang Zhen Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第2期301-305,共5页
Hydroxyl radicals(·OH) generated on anode play a vital role in electrochemical oxidation(EO) of organic pollutants for water treatment. Inspired by the four-electron oxygen evolution reaction(OER), we supposed an... Hydroxyl radicals(·OH) generated on anode play a vital role in electrochemical oxidation(EO) of organic pollutants for water treatment. Inspired by the four-electron oxygen evolution reaction(OER), we supposed an anode-selection strategy to stabilize deeply oxidized states(*O and*OOH) which are beneficial to generating·OH. To verify the hypothesis, a candidate anode component(MIL-101(Cr), a well-known metal-organic framework with active variable-valence transition metal centers) was used to coat Ti/TiO_(2)plate to fabricate anodes. Compared to TiO_(2)(101) plane on undecorated anode surface, fast and complete removal of aniline and phenol, and improved energy utilization were achieved on MIL-101(Cr)-coatedTi/TiO_(2)anode. Mechanism investigation, including pollutant degradation pathways, showed the predominate contribution(69.60%–75.13%) of·OH in pollutant mineralization. Density functional theory(DFT)computations indicated Cr site in MIL-101(Cr) was more conducive to stabilizing*O and*OOH, leading to thermodynamical spontaneous generation of·OH. This work opens up an exciting avenue to explore·OH production, and supplies a useful guidance to the development of anode materials for EO process. 展开更多
关键词 Active oxidation species Electrocatalytic oxidation DFT computation MOF Hydroxyl radical Composite anode
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