氢氧直接合成过氧化氢用PdO/γ-Al2O3催化剂过渡金属改性研究

采用等体积浸渍法制得过渡金属改性的系列催化剂MOx-PdO/γ-Al2O3 (M=La、Mn、Ni、Ce).在10℃、常压下考察了过渡金属种类及氧化镧负载量对催化剂MOx-PdO/γ-Al2O3催化氢氧直接合成过氧化氢性能的影响.采用能谱(EDS)、X射线衍射(XRD)、程序升温还原(H2-TPR)等手段对催化剂进行表征分析.结果表明,经过渡金属改性后的MOx-PdO/γ-Al2O3催化剂活性高于未改性的催化剂PdO/γ-Al2O3;以镧为助剂制得的La2O3-PdO/γ-Al2O3(氧化镧质量分数为1％、氧化钯质量分数为2.5％)催化剂性能优于其他过渡金属改性的催化剂,与PdO/γ-AhO3相比,所得过氧化氢的浓度、收率、选择性分别提高了76.54％、76.61％、44.21％.     

A continuous method to prepare porous polystyrene membranes with high adsorption ability for polycyclic aromatic hydrocarbons

A convenient and continuous method to prepare porous polystyrene (PS) membranes via a microlayer coextrusion and template method is proposed. The porous PS membranes can be obtained via the acid etching of a CaCO₃ template embedded in the membranes. Scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy of the porous PS membranes show that most of the CaCO₃ particles can be etched away. The effects of etching time, CaCO₃ content, and membrane thickness on the porous structures are investigated, which can be used to regulate and control the porous structure. To demonstrate the adsorption performance of porous PS membranes on polycyclic aromatic hydrocarbons, pyrene is used as the model compound. Compared with that of solid PS membranes, porous PS membranes exhibit much higher adsorption performance for trace pyrene. The adsorption kinetics and isotherm of porous PS membranes can be well fit by pseudo‐second‐order kinetics and a Freundlich isotherm model. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45917.     

Study on the relationship between the particle size distribution and the effectiveness of the K‐powder fire extinguishing agent

The relationship between the particle size distribution and the extinguishing effectiveness of the new K‐powder fire extinguishing agent has been studied experimentally, to explore the reason of the great extinguishing efficiency exhibited by the new K‐powder fire extinguishing agent on Class B fire (liquid fuel fire). The results of the experiment showed that the extinguishing effectiveness increased along with the decrease of the particle size distribution. In addition, a sharp discontinuity appeared around the limiting size, about 40 μm. The powder with the particle size below 40 μm exhibited highly effective extinguishing with the minimum effective extinguishing concentration C_xr = 23 g·m^?3, while the powder with the particle size above 40 μm exhibited little fire extinguishing efficiency. Compared with other fire extinguishing agents produced by different substances, the new K‐powder fire extinguishing has the bigger limiting size. That means, in the same particle size distribution, the new K‐powder fire extinguishing agent contains more highly effective powder than others contain, and is more effective.     

Synthesis of an Alkyl Polyoxyethylene Ether Sulfonate Surfactant and Its Application in Surfactant Flooding

Surfactant flooding as a potential enhanced oil‐recovery technology in a high‐temperature and high‐salinity oil reservoir after water flooding has attracted extensive attention. In this study, the synthesis of an alkyl alcohol polyoxyethylene ether sulfonate surfactant (C₁₂EO₇S) with dodecyl alcohol polyoxyethylene ether and sodium 2‐chloroethanesulfonate monohydrate, and its adaptability in surfactant flooding were investigated. The fundamental parameters of C₁₂EO₇S were obtained via surface tension measurement. And the ability to reduce oil–water interfacial tension (IFT), wettability alteration, emulsification, and adsorption was determined. The results illustrated that IFT could be reduced to 10^?3 mN m^?1 at high temperature and high salinity without additional additives, and C₁₂EO₇S exhibited benign wettability alternate ability, and emulsifying ability. Furthermore, the oil‐displacement experiments showed that C₁₂EO₇S solution could remarkably enhance oil recovery by 16.19% without adding any additives.     

Fabrication of ZrB2-SiC ceramic composites by optimized gel-casting method

The ZrB₂-SiC ceramics with homogenous microstructures were successfully fabricated by the optimized gel-casting method and pressureless sintering. The effects of the processing parameters, including the monomer content, cross-linker/monomer ratios, initiator addition, catalyst concentration and polymerization temperature, on the final gel properties were systematically investigated. The rheological behavior and stability of ZrB₂-SiC suspensions were evaluated, and the microstructures and mechanical properties of sintered ceramics were also analyzed. The homogenous gel networks containing low monomer content (4 wt%) and without catalysts had been successfully obtained, which could be mainly attributed to the homogeneous distribution of crosslinking points and temperature-induced gelation. The crack-free and complex-shaped ZrB₂-SiC ceramic composites were achieved by the optimized gel-casting, which could reach the highest relative density of 97.2% and the flexural strength of 402 ± 57 MPa, respectively. This study provides an optimized gel-casting process for fabricating ZrB₂-SiC ceramics with excellent properties by low colloidal additives and without catalysts.     

掺杂铁离子和铜离子的TiO2光催化剂的研究

利用钛酸正四丁酯水解制备了几种不同浓度的TiO2胶体,在降解甲基橙后发现,R（乙醇与水物质的量比）值为1／50的0．01mol／L TiO2胶体降解效果最好。在不同的pH值、反应温度、搅拌速度下制备了同时掺杂铁离子和铜离子的R值为1／50的0．01mol／L TiO2胶体,通过光降解甲基橙,发现pH值、反应温度、搅拌速度和掺杂离子浓度对TiO2胶体的形态、掺杂效果和光催化活性均有影响。对比纯TiO2胶体的光降解甲基橙效果发现,掺杂铁离子和铜离子的TiO2光催化剂在pH值2．0、低搅拌速度、室温情况下,具有更好的光催化活性。     

Insulation performance and microstructure in modified polyethylene by MPE

Electrical measurements have shown to be able to provide useful information on physical, chemical, and microstructural properties of dielectric material. In this article, the depolarization characteristics of low‐density polyethylene blended with a small amount of metallocene catalyzed polyethylene were measured by pulsed electro‐acoustic method under various stresses. According to space charge limited current theory, the derivation of quantities such as mean volume density of space charge, apparent trap‐controlled mobility, trap depth distribution, and threshold stress were discussed. The test results showed that low‐density polyethylene blended with 1 wt % metallocene catalyzed polyethylene could effectively decrease deep trap density, increase shallow trap density, and then improve the mobility of charges. We also measured the breakdown voltage and tensile strength of the blends. It was found that low‐density polyethylene blended with a small amount of metallocene catalyzed polyethylene could effectively improve its breakdown voltage and tensile strength but reduce the material tenacity. Finally, mechanical relax and crystalline morphology of blends were studied by dynamic mechanical measurement, wide‐angle X‐ray diffraction, and small‐angle X‐ray scattering experiments. The results showed that the improvement of electrical properties and mechanical strength in the blends were relevant to the crystalline morphology. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

抗蚀水泥的组分设计与性能研究

主要研究在水玻璃激发条件下,矿渣、粉煤灰、水泥按一定的配合比配制成复合胶凝材料,并对这种复合胶凝材料的抗硫酸盐侵蚀性能进行研究。试验采用正交实验法,以获得高抗硫酸盐侵蚀能力的复合胶凝材料的最优配比;并采用XRD、SEM和MIP等手段对其机理进行了研究探讨。结果表明:(1)掺加矿物掺和料的水泥比普通硅酸盐具有更好的抗硫酸盐侵蚀性能;(2)试验条件下的高抗硫酸盐侵蚀能力的复合胶凝材料的最佳配比为:矿物掺合料与水泥的掺量比为7:3,矿物掺合料中矿渣与粉煤灰掺量比为4:6,水玻璃掺量与矿物掺合料总量比为7%。     

Kinetic study of Diels–Alder reaction involving in maleimide–furan compounds and linear polyurethane

Linear polyurethane was synthesized by Diels–Alder (DA) reaction between a polyurethane prepolymer end-capped with furan rings (MPF) and bismaleimide (BMI). The polymerization kinetics were studied following a preliminary kinetic study of the DA reaction between furfuryl alcohol (FA) and BMI compounds by attenuated total reflection infrared, ultraviolet–visible and in situ ¹H NMR spectroscopies, where in situ ¹H NMR spectroscopy was selected as the analytical method of choice to study the DA reaction between MPF and BMI. The results showed that the reaction followed second-order kinetics, and the most beneficial experimental conditions to maximize conversion were identified.     

活性炭表面性质对染料废水生化出水深度净化效果的影响

不同种类活性炭对实际废水的吸附效果差异很大,由此对某大型染料生产厂的染料废水生化出水进行了活性炭吸附实验研究,对具有不同表面性质的活性炭的吸附效果进行了比较,探讨了染料废水生化出水吸附效果与活性炭表面官能团、吸附指标、比表面积之间的关系。结果表明,活性炭的吸附作用不仅与活性炭比表面积有关,还与孔结构有密切关系;染料废水生化出水中的溶解性有机物与活性炭表面碱基团可通过氢键、静电作用在活性炭表面吸附。