Investigation on preparation of CuO-SnO2 -CeO2γ-Al2O3 catalysts for catalytic wet air oxidation process and their catalytic activity for degradation of phenol

Catalytic Wet Air Oxidation process is an efficient measure for treatment of wastewater with great strength which is not biodegradable. Heterocatalysts now become the key investigation subject of catalytic wet air oxidation process due to their good stability and easy separation. In the paper, CuO-SnO2-CeO2/γ-Al2O3 catalysts are prepared by impregnation method, with SnO2 as a doping component, CuO as an active component, CeO2 as a structure stabilizer, γ-Al2O3 as a substrate. XPS test is carried out to investigate the effect of Sn on the chemical surrounding of Cu and O element on the catalyst surface and their catalytic activity. It is shown that the right doping of Sn can increase Cu content on the catalyst surface, as a result the quantity of adsorption oxygen is also increased. It is found that Cu content on the catalyst surface is one of the primary factors that determin catalytic activity of catalyst through analyzing the catalytic wet air oxidation process of phenol.     

Failure analysis of corrosion cracking and simulated testing for a fluid catalytic cracking unit

The failure of a fluid catalysis and cracking unit (FCCU) in a Chinese refinery was investigated by using nondestructive detection methods, fracture surface examination, hardness measurement, chemical composition and corrosion products analysis. The results showed that the failure was caused by the dew point nitrate stress corrosion cracking. For a long operation period, the wall temperature of the regenerator in the FCCU was below the fume dew point. As a result, an acid fume NOx-SOx-H2O medium presented on the surface, resulting in stress corrosion cracking of the component with high residual stress. In order to confirm the relative conclusion, simulated testing was conducted in laboratory, and the results showed similar cracking characteristics. Finally, some suggestions have been made to prevent the stress corrosion cracking of an FCCU from re-occurring in the future.     

Ship-in-bottle synthesis of NaY zeolite encapsulated Cosalen complex and its catalytic performance for cyclohexane oxidation

N, N’-bis (salicylidene) ethylenediiminocobalt (Cosalen) was encapsulated into microporous NaY zeolite via the technique of “ship-in-bottle”. The encapsulated complex (Cosalen-NaY) was characterized by Fourier-transform infrared spectrum, ultraviolet-visible spectrum, Brunauer-Emmett-Teller surface areas, X-ray diffraction, thermogravimetry-differential thermal analysis and scanning electron microscope. The reaction of cyclohexane oxidation using oxygen was chosen to investigate the catalytic performance of Cosalen-NaY, and the effects of oxygen pressure, temperature and reaction time were also studied. The results show that Cosalen complex is encapsulated into the supercage of the zeolite and the structure of NaY zeolite remains integrity and the thermal stability of Cosalen is greatly enhanced after encapsulation. Cosalen-NaY shows the better activity in the oxidation of cyclohexane without reductant and solvent. The conversion of cyclohexane is up to 13.4% at 150 ℃ for 3 h under oxygen pressure of 0.85 MPa, with the higher total selectivity to cyclohexanol, cyclohexanone, cyclohexyl hydroperoxide (CHHP) and acid (79.2%) than the neat complex (55.5%). NaY zeolite carrier maybe contributes to the results. There is no obvious induction period to initiate the reaction; furthermore, the amount of CHHP among the products is small, which indicates that the Cosalen-NaY has the strong ability to accelerate the decomposition of CHHP. Recycling tests show that the hybrid material can be used repeatedly with a negligible loss of active sites.     

Preparation,characterization of superacid SO4 2−/ZrO2-SiO2 and its activity on catalytic synthesis of methyl p-nitrobenzoate

Solid superacid SO42-/Zr O2-SiO2 was prepared by dip-impregnation method, and its catalytic activity was tested with esterification of p-nitrobenzoic acid and methanol. The optimum conditions were also found, that is, the molar ratio between silica and zirconia was 10:1, the calcination temperature was 550 ℃ and the soaked consistency of H2SO4 was 1.0 mol?L-1. Under the conditions that the ratio of methanol to acid(m L/g) was 12:1, the amount of catalyst was 0.5 g, the reaction time was 5 h and the stirring speed was 800 r?min-1, the yield of methyl p-nitrobenzoate could reach up to 90.5%. Then the characterizations of cataslyst, including the acidity and types of acidic centers, specific surface area and surface structure was respectively examined by Hammett indicator, in-situ pyridine IR, BET method, FT-IR(KBr), transmission electron microscope(TEM), and X-ray diffraction(XRD). The results showed that the catalyst SO42-/Zr O2-SiO2 was superacid with high specific surface area due to Ho-12.70. It contained acidic sites of Lewis and BrΦnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.     

Preparation of ultrafine α-Al_2O_3 powders by catalytic sintering of ammonium aluminum carbonate hydroxide at low temperature

1 INTRODUCTIONUltrafine alumina with extensively excellentproperties such as high heat resistance ,high corro-sion resistance ,good electrical insulation and cata-lytic abilities , etc ,is a very i mportant branch ofultrafine powder materials and widely applied infields of ceramics , metallurgy , electron and cata-lysts[1 ,2]. The thermal decomposition of ammoni-umaluminum carbonate hydroxide ( AACH) is anew method developed in recent years for produ-cing ultrafine alumina powders , and …     

Preparation of uitrafine α-Al2O3 powders by catalytic sintering of ammonium aluminum carbonate hydroxide at low temperature

The precursor of ammonium aluminum carbonate hydroxide was synthesized by using aluminum sulfate （Al2 （SO4）3 ） and ammonium carbonate（（NH4 ）2CO3 ）. The effects of α-Al2 O3 seeds and mixture composed of α- Al2O3 and ammonium nitrate, as well as multiplex catalysts （AT） on phase transformation of alumina in sintering process were investigated respectively. The results show that the α-Al2 O3 seeds and the mixture of α-Al2 O3 and ammonium nitrate can lower the phase transformation temperature of α-Al2O3 to different extents while the particles obtained agglomerate heavily. AT has great potential synergistic effects on the phase transformation of alumina and reduces the phase transformation temperature of α-Al2O3 and the trends of necking-formation between particles. Therefore the dispersion of powder particles is improved significantly.     

Storage of hydrogen in floating catalytic carbon nanotubes after graphitizing

Hydrogen storage under moderate pressure (~10 MPa) and ambient temperature (~25℃) in multi-walled carbon nanotubes (MWNTs) prepared by the floating catalyst method is investigated. The capacity of hydrogen adsorption is evaluated based on both the nanotubes diameter and morphology. Indirect evidence indicates that hydrogen adsorption not only occurs on tube surface and interiors, but also in tube interlayers. The results show that the floating catalytic carbon nanotubes might be a candidate hydrogen storage material for fuel cell electric vehicles.     

Selective catalytic reduction of NO with NH3 over sol-gel-derived CuO-CeO2-MnOx/γ-Al2O3 catalysts

Granular CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. Preliminary tests were carried out to analyze the behavior of NH₃ and NO over catalyst in the presence of oxygen. The optimum temperature range for SCR over the CuO-CeO₂-MnO _x /γ-Al₂O₃ catalysts is 300–400 °C. The catalysts maintain nearly 100% NO conversion at 350 °C. The °C NH₃ oxidation experiments show that both NO and N₂O are produced gradually with the increase of temperature. The catalysts in this experiment have a stronger oxidation property on NH₃, which improves the denitrification activity at low temperature. The over-oxidation of NH₃ at high temperature is the main cause leading to a decrease in the NO conversion. The NH₃ and NO desorption experiments show that NH₃ and NO can be adsorbed on CuO-CeO₂-MnO _x /γ-Al₂O₃ granular catalysts. The transient response of NH₃ and NO indicates that the SCR reaction proceeds in accordance with the Eley-Rideal mechanism. The adsorbed NO has little influence on the denitrification activity in SCR process. Foundation item: Projects (50776037, 50721005) supported by the National Natural Science Foundation of China     

Precipitation of antimony from the solution of sodium thioantimonite by air oxidation in the presence of catalytic agents

The behavior of antimony oxidation in the solution of sodium thioantimonite was studied in the presence of catalytic agents. The catalytic effects of the respective addition of cupric sulfate, sodium tartrate, potassium permanganate, phenol, 1,2-dihydroxybenzene and their combination on the oxidation of sodium thioantimonite were investigated. A pilot test was carried out. The results show that the respective use of sodium tartrate, cupric sulfate, potassium permanganate, phenol and 1,2-dihydroxybenzene have little catalytic effect on the oxidation of sodium thioantimonite. However there exists obvious catalytic oxidation by the combination of 0.25 g/L 1,2-dihydroxybenzene, 0.5 g/L potassium permanganate and 1.0 g/L phenol. Moreover, high blast intensity, the increase of temperature and NaOH concentration favor the oxidation of antimony. The oxidation process of antimony has such advantages as quick reaction and low operation costs. The results of the pilot test are consistent with those of laboratory experiments.     

Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter

1　INTRODUCTIONImperialSmeltingProcess (ISP) ,isaprocessavailableforproductionofzincandlead .Atpresent,about 13operatingISPsmeltersproduceabout 13%ofglobalzincandlead[1] .ButISPisasignificantcontributortoindustrialgreenhouseandacidityemis sionsduetoitshighenergyconsumption .Althoughcellemissionshavebeenreducedconsiderablyinre centyears ,thegrowingglobalconcernonenviron mentalissuesisimposingpressureontherelatedcom paniestoreducetheiremissions .Becauseofthelargenumberoffeedstreams ,by…     

Eleetrodeposition and Characterization of CulnSe2 Thin Films for Solar Cells

CulnSe2 （CIS） thin films were prepared by electrodeposition from the de-ionized water solution consisting of CuCl2, InCl3, H2SeO3 and Na-citrate onto Mo/soda-lime glass （SLG） substrates. A thermal processing in Se atmosphere at 450℃ was carried out for the electrodepositied films to improve the stoichiometry. The composition and morphology of selenized CIS thin films were studied using energy dispersive spectroscopy （EDS） and scanning electron microscopy （SEM）, respectively. X-ray diffraction （XRD） studies show that the annealing in Se atmosphere at 450℃ promotes the structural formation of CIS chalcopyrite structure.     

Synthesis and Performance of LiMnO_2 as Cathodes for Li-ion Batteries

1　IntroductionLithiummanganates (LiMn2 O4 orLiMnO2 )areoftensuggestedascathodematerialsforlithiumionbatteries,andhavebecomeofmajorinterestlatelybecausemanga neseisnotonlyrelativelyinexpensivebutalsohasthede siredpropertiesfortheelectrode.Inparticular,spinel typelithiummanganate(LiMn2 O4)hasbeenstudiedandisknowntoexhibitexcellentrechargeableproperties.Assuch,thisspinelcompoundhasapotentialforpracticaluseinthenearfuture[1].Asecondlithiummanganate,LiMnO2 compoundshavetwostructure types,orth…     

Electrodeposition and Characterization of CuInSe_2 Thin Films for Solar Cells

CuInSe2 (CIS) thin films were prepared by electrodeposition from the de-ionized water solution consisting of CuCl2, InCl3, H2SeO3 and Na-citrate onto Mo/soda-lime glass (SLG) substrates. A thermal processing in Se atmosphere at 450 ℃ was carried out for the electrodepositied films to improve the stoichiometry. The composition and morphology of selenized CIS thin films were studied using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. X-ray diffraction (XRD) studies show that the annealing in Se atmosphere at 450 ℃ promotes the structural formation of CIS chalcopyrite structure.     

UV/TiO2 and UV/TiO2-film for Degradation of Textile Dyes

Wastewaters fromtextile and dyeingindustries are highly colored by various non-biodegradable dyes whichcause serious environ-mental problems[1].The effluents of the wastewater introduced not only color but alsotoxicityinto aquatic system.The conventionalt…     

Effect of TiB_2 content on resistance to sodium penetration of TiB_2/C cathode composites for aluminium electrolysis

1　INTRODUCTIONInrecent years ,therehavebeenincreasingeffortstoimprovetheHall Heroult processintheprimaryaluminiumindustry[1 ] .InordertoovercometheshortagesofHall Heroultprocess ,suchashighconsumptionofelectricalpower ,highconsumptionofcarbonanodeandserious pollutionduetocarbonanodemanufactureandconsumptionetc ,anoveltypeofaluminareducedcellsbasedoninertanodeandwettablecathodesystemwasdevelopedtoreplaceconventionalHall Heroultprocess[2 ,3 ] .Titaniumdiboride(TiB2 )appearstobethebestca…     

Research on atomic states, physical properties and catalytic performance of Ru metal

Using the one-atom theory (OA) of pure metals, the atomic states of Ru metal with hcp structure, fcc structure, bcc structure and liquid state were determined as fol- lows: [Kr](4dn)3.78(4dc)2.22(5sc)1.77(5sf)0.23,Ψa(fcc-Ru)=[Kr](4dn)3.70(4dc)2.44 (5sc)1.42(5sf)0.44, Ψ a(bcc-Ru)=[Kr](4dn)4.00(4dc)2.22(5sc)1.56(5sf)0.22, Ψ a(L-Ru)=[Kr](4dn)4.00(4dc)2.00(5sc)1.52 (5sf)0.48. The potential curve and physical properties as a function of temperature for hcp-Ru such as lattice constant, cohesive energy, linear thermal expansion coeffi- cient, specific heat and Gibbs energy and so on were calculated quantitatively. The theoretical results are in excellent agreement with experimental value. The rela- tionship between the atomic states and catalytic performance was explained qualitatively and these supplied the designation of Ru metal and relative materials with theoretical instruction and complete data.     

Phase and Rietveld Refinement of Pyroehlore Gd_2Zr_2O_7 Used for Immobilization of Pu （Ⅳ）

The phase of pyrochlore Gd_2Zr_2O_7 used for immobilization of Pu （Ⅳ） was investigated, tetravalent cerium was used as the simulacrum for plutonium with tetravalence, and the compounds in the system Gd_2Zr_2-_xCe_xO_7 （0.0≤x≤2.0） were synthesized via a high temperature solid reaction method with Gd_2O_3 and ZrO_2 powders being used as the starting materials. Based on the collected XRD data of the gained samples, the phase and microstructural change of compounds were calculated by means of rietveld structural refinement method. The experimental results indicated that the phases of compounds were changed from pyrochlore to fluorite-type phase with the increasing x. The linear relation between a and x was discovered in the range of fluorite-type phase, which accorded with a = 0.52748 ＋ 0.00825 x （0.2≤x≤2.0）, while V= 0.14668 ＋ 0.00711 x （0.2≤x≤2.0） was also achieved.     

Phase and Rietveld Refinement of Pyrochlore Gd_2Zr_2O_7 Used for Immobilization of Pu(Ⅳ)

The phase of pyrochlore Gd2Zr2O7 used for immobilization of Pu(Ⅳ) was investigated, tetravalent cerium was used as the simulacrum for plutonium with tetravalence, and the compounds in the system Gd2Zr2-x Ce x O7(0.0 x 2.0) were synthesized via a high temperature solid reaction method with Gd2O3 and ZrO2 powders being used as the starting materials. Based on the collected XRD data of the gained samples, the phase and microstructural change of compounds were calculated by means of rietveld structural refinement method. The experimental results indicated that the phases of compounds were changed from pyrochlore to fluorite-type phase with the increasing x. The linear relation between a and x was discovered in the range of fluorite-type phase, which accorded with a = 0.52748 + 0.00825 x(0.2 x 2.0), while V = 0.14668 + 0.00711 x(0.2 x 2.0) was also achieved.     

Microwave Synthesis of Cathode Material LixMn2O4 for Lithium-ion Battery

LixMn2O4 was synthesized rapidly by microwa heaing,the product phases of the microwave synthesis and comventional solid-solid-state synthesis were comparatively inesitigated,The capacity of microwave synthesis product decreases relatively slow,The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling .But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting,Tehe influential factors of the process parameters are discussed such as heat preservation time,pre-heating at 400℃ for 24 h and coupled agent.