硅藻土特性对复合绝缘子人工污秽试验的影响

复合绝缘子的耐污闪性能主要受硅橡胶材料的憎水性和憎水迁移特性的影响,复合绝缘子人工污秽试验中,不溶污秽的特性对硅橡胶的憎水迁移性有很大的影响,因此在复合绝缘子人工污秽试验中选用合适的不溶污秽对试验结果的可对比性具有至关重要的意义。对6种不同硅藻土在高温硫化硅橡胶(HTV)和室温硫化硅橡胶(RTV)表面进行了憎水迁移性试验,研究了不同硅藻土特性对材料憎水迁移性的影响,并进行了不同污秽类型的电镜扫描和比(BET)表面积、孔隙度的研究。试验结果表明,不同的硅藻土对硅橡胶表面憎水性的迁移速度有很大的影响,且与其微观特性有着比较好的相关性。根据试验结果对人工污秽试验所用硅藻土的特征值进行了推荐。该文的研究结果可以作为分析硅橡胶材料憎水迁移特性的参考,同时也为复合绝缘子人工污秽试验的标准制定提供了一定的依据。

Regeneration of waste SCR catalyst by air lift loop reactor

A solution of 0.1 mol/L to 1.0 mol/L H2SO4 can dissolve alkali metals and alkaline earth metals which weaken an active site of SCR catalyst. The waste catalyst washed with 0.5 mol/L H2SO4 regained the best catalytic activity. When a concentration of the sulfuric acid is less than 0.5 mol/L, sufficient cleaning effects cannot be obtained. In contrast, when the concentration is greater than 1.0 tool/L, the active components, vanadium and tungsten are undesirably eluted. The total BET surface of the catalyst regenerated by air lift loop reactor showed almost the same as that of fresh catalyst due to the removal of insoluble compounds which may be penetrated into pores of catalyst. The addition of a solution of 0.075 mol/L ammonium vanadate （NHnVO3） and 0.075 mol/L ammonium paratungstate （5（NH4）20· 12WO3-5H20） to 0.1 mol/L H2SO4 significantly increases the activity of the waste catalyst.

Influence of Alumina Content on Catalytic Performance of PtSn/Al_2O_3/SBA-15 Catalysts for Propane Dehydrogenation

The alumina-modified SBA-15 （A12OJSBA-15） zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface area mea- surements, hydrogen chemisorption, FT-IR spectroscopy, NH3-TPD, XPS and TPO techniques were used to characterize the catalysts. Test results showed that the addition of alumina not only could modify the acid function of the support but also the structure of the metallic phase, thus affecting their catalytic properties. Among these catalysts studied, the PtSn/AI203 （5%）/ SBA-15 catalyst exhibited a best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance might be attributed to the relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn species.

Effect of incorporation manner of Zr promoter on precipitated ironbased catalysts for Fischer-Tropsch synthesis

The promotional effects of Zr on the structure, reduction, carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis （FTS） catalysts were investigated. The catalysts were characterized by N2 physisorption, temperature-programmed reduction （TPR）, and M6ssbauer effect spectroscopy （MES） techniques. As revealed by N2 physisorption, Zr decreased the BET surface area and pore volume of the catalyst. The results of TPR and MES show that Zr suppresses the reduction and carburization of Fe catalysts because of the interaction between Fe and Zr. The FTS reaction results indicate that Zr decreases the FTS activity of Fe catalysts but improves the catalysts＇ stability. In addition, Zr promoter restraines the formation of light hydrocarbons （methane and C2-C4） and shifts the production distribution to the heavy hydrocarbons.

Improvement of visible light-induced photocatalytic performance by Cr-doped SrTiO_3-carbon nitride intercalation compound (CNIC) composite

Novel organic-inorganic composite photocatalyst offers new opportunities in the practical applications of photocatalysis. Novel visible light-induced Cr-doped Sr Ti O3–carbon nitride intercalation compound(CNIC) composite photocatalysts were synthesized. The composite photocatalyst was characterized by X-ray diffraction(XRD), field-emission scanning electron microscopy(FESEM), high-resolution transmission electron microscopy(HRTEM), Fourier transform infrared(FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence(PL) spectroscopy, and BET surface area analyzer. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange(MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. For maximizing the photodegradation activity of the composite photocatalysts, the optimal CNIC content was determined. The improved photocatalytic activity of the as-prepared Cr-doped Sr Ti O3–CNIC composite photocatalyst may be attributed to the enhancement of photo-generated electron–hole separations at the interface.

Highly Active and Stable Ni_2P/SiO_2 Catalyst for Hydrogenation of C_9 Petroleum Resin

Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reduction（TPR） method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity（LHSV） was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values（250 mg Br/100g） within 300h, showing the high activity and stability of Ni2P/SiO2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction（XRD）, BET surface area（BET） analysis, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared（FTIR） pyridine adsorption, and X-ray photoelectron spectroscopy（XPS）. Compared with the traditional sulfurated-Ni W catalysts, Ni2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni2P/SiO2 catalyst. The stability of Ni2P/SiO2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni2P nanoparticles and weak surface acidity for the Ni2P/SiO2 catalyst.

The performance of nano multicomponent cocatalyst in the improvement of catalytic sensor of methane

Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_3 were prepared via sol-gel technique inthe experiment.BET surface area, catalytic activity and thermal stability were tested andcompared.It is found from the experiment that the Ce-doped Al_2O_3 vector possesseshigher catalytic activity than pure Al_2O_3 vector.Zr-doped Al_2O_3 vector can enhance thethermal stability of methane sensors.Ce-Zr-Al solid solution can be obtained by the presenceof Ce and Zr doped with Al_2O_3.The reaction activity and thermal stability of catalyticsensors were improved because of the unique synergy effect from Ce-Zr-O.Among themixed cocatalysts, Ce-Zr-O was reported to be an excellent cocatalyst material.The performanceof methane sensors can be improved significantly via the modification ofCe-Zr-Al_2O_3 vector.

Removal of elemental mercury by modified bamboo carbon

The mercury removal performance of modified bamboo charcoal （BC） was investigated with a bench-scale fixedbed reactor, A simple impregnation method was used to modify the BC with ZnCI2 and FeCI3 separately. BET and XPS were used to determine the pore structure and surface chemistry of the sorbents. The role of Fe3 ＋ in the removal of elemental mercury by modified sorbents was discussed. The experimental results suggest that the modified BCs have excellent adsorption potential for elemental mercury at a relatively higher temperature, 140 ℃. The BET surface area and average pore size of modified sorbents do not show noticeable priority compared to unmodified BC, XPS spectra indicate that Fe atoms mainly exist in the form of Fe3 ＋ for the FeC1j-impregnated BC. Better performance of FeCl3-impregnated BC at different temperatures （20, 140 and 180 ℃） suggests the enhancement of non-chloride functional groups （Fe3 ＋）. Inhibition effect of SOx and NO for Hg removal by BC samples is present in the study.

Effect of pyrolysis temperature on properties of ACF/CNT composites

Activated carbon fiber/carbon nanotube(ACF/CNT) composites were fabricated by chemical vapor deposition(CVD) process.The effects of pyrolysis temperature on properties of ACF/CNT composites,including BET specific surface area,mass increment rate and adsorption efficiency for rhodamine B in solution,were investigated by scanning electron microscopy.The results show that the pyrolysis temperature is a key factor affecting the qualities of ACF/CNT composites.The mass increment rate and BET specific surface area sharply decrease with the increase of pyrolysis temperatures from 550 ℃ to 850 ℃ and the minimum diameter of CNTs appears at 750 ℃.The maximum adsorption efficiency of ACF/CNT composites for rhodamine B is obtained at 650 ℃.ACF/CNT composites are expected to be useful in adsorption field.

Exploring aramid as emerging contender for CO_2 capture

To prevent CO_2 accumulation in the atmosphere generated from scorching of fossil fuels, carbon capture and sequestration(CCS) technology is considered as a potential route to mitigate the emissions of CO_2 from reaching the atmosphere. Power generation from sources such as gas, coal and biomass can fulfill the energy demand more readily than many other sources of electricity production. Thus these sources may be retained as important alternative option in the global energy cycle. In order to curtail CO_2, porous aramid network was fabricated by the condensation of 1,3,5-benzenetricarbonyl trichloride and 1,3-phenylenediamine in 1,4-dioxane solvent. Aramid was characterized for various analyses including FTIR, XRD, TGA, BET surface area and pore size analysis, FESEM and CO_2 adsorption measurements. Excellent thermal stability was provided by strong amide linkages in the polymer backbone. Optimum CO_2 uptake of aramid was achieved to be 23.14 mg·g^(-1) at 273 K at 0.1 MPa. The basic amide groups of network structure showed greater affinity for CO_2.Excellent thermal stability of aramid makes it a promising sorbent for CO_2 capture in adverse conditions.

Physicochemical Properties and Gasification Reactivity of the Ultrafine Semi-char derived from a Bench-scale Fluidized Bed Gasifier

Zhtmdong coalfield is the largest intact coalfield worldwide and fluidized bed gasification has been considered as a promising way to achieve its clean and efficient utilization. The purpose of this study is to investigate the phy- sicochemical properties and gasification reactivity of the ultrafme semi-char, derived from a bench-scale fluidized bed gasifier, using Zhundong coal as fuel. The results obtained are as follows. In comparison to the raw coal, the carbon and ash content of the semi-char increase after partial gasification, but the ash fusion temperatures of them show no significant difference. Particularly, 76.53% of the sodium in the feed coal has released to the gas phase after fluidized bed gasification. The chemical compositions of the semi-char are closely related to its particle size, attributable to the distinctly different natures of diverse elements. The semi-char exhibits a higher graphitization degree, higher BET surface area, and richer meso- and macropores, which results in superior gasification reactiv- ity than the coal char. The chemical reactivity of the semi-char is significantly improved by an increased gasifica- tion temperature, which suggests the necessity of regasification of the semi-char at a higher temperature. Conse- quently, it will be considered feasible that these carbons in the semi-char from fluidized bed gasitiers are rec- laimed and reused for the gasification process.

Photoactivity of titanium dioxide/carbon felt composites prepared with the assistance of supercritical carbon dioxide: Effects of calcination temperature and supercritical conditions

TiO2-coated carbon felt(TCF)composite catalysts have been prepared via a supercritical treatment of titanium tetraisopropoxide(TTIP)as the precursor.The physical properties of the catalysts were characterized by means of thermogravimetric and differential thermal analysis(TG–DTA),X-ray diffraction(XRD),fluorescence spectroscopy,scanning electron microscopy (SEM),and BET surface areas techniques.The photocatalytic activities of the materials were evaluated using the degradation of Congo red(CR)as a probe reaction.All the composites showed much higher photocatalytic activity than commercial P25 due to significant synergistic effects.Reused TCF retained high photocatalytic activity for degradation of CR.The photocatalytic efficiency in CR degradation was found to be strongly dependent on the TiO2-coating ratio and calcination temperature.A possible mechanism for the enhanced reactivity involves shuttling of electrons from TiO2 particles to the carbon felt(CF)as a result of an optimal arrangement in TCF that stabilizes charge separation and reduces charge recombination.In addition to the significant synergistic effects,the abundant spaces between adjacent carbon fibers allow UV light to penetrate into the felt-like photocatalyst to a considerable depth,so that a three-dimensional environment is available for the photocatalytic reaction.

Preparation of nano-porous AlN micro-rods

In this paper, nano-porous A1N micro-rods were prepared and characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Brunauer-Emett-Teller （BET） method of nitrogen adsorption at low temperature, UV-via absorption spectrometry and Raman spectrometry. The SEM images and TEM images showed that the A1N samples were micro-size rods with pores in their surfaces evenly. The length of the rod was in the range of a few mi- crons to tens of micron, the diameter of the rods was about one micron, the diameter of the pore was about hundreds of nano- meter and the wall thickness of the pore about tens of nanometer. The BET surface area of the sample was 41.424 ma/g. The optical spectra showed that the optical properties of the A1N samples almost agreed with that of A1N bulk or film.