Preparation and antifouling performance of thin inorganic ultrafiltration membrane via assisted sol-gel method with different composition of dual additives

A novel TiO₂ thin film was prepared on the ceramic hollow fiber by the sol-gel method using poly(vinylpyrrolidone) (PVP) and polyvinyl alcohol (PVA) as additives. SEM images verified the formation of TiO₂ layer with various thickness using different composition of titania sols. The effect of the PVP and PVA contents on the TiO₂ sol properties, the separation and the antifouling performance of the ultrafiltration membranes were investigated thoroughly. When the contents of PVP and PVA were 1.0 wt% and 0.8 wt%, respectively, the resultant membrane showed a thickness of 0.55 μm with a pure water flux of 255 L m^?2 h^?1. In addition, the adherent foulant bovine serum albumin was applied to evaluate the antifouling performance. During the three fouling-recovery cycles, the flux recovery ratio and the flux decay ratio maintained about 99% and 30%. The BSA flux and rejection were still 169 L m^?2 h^?1 and 96.9% after the cycles, indicating a superior antifouling property.     

高应力软岩巷道锚注一体化联合支护技术应用

介绍了国家专利注锚剂、中空注浆锚索等产品,以国家能源麦朵山煤矿11采区2煤辅助运输巷为研究对象,采用数值模拟、理论分析、现场测试及井下试验相结合的综合研究方法,对11采区2煤辅助运输巷采用锚注一体联合支护技术,来实现对岩体裂隙注浆,使浆料与岩体结为一体,在围岩与支护体共同作用过程中,实现强岩增荷的作用,维护巷道的稳定性,实现工作面的安全生产。     

Synthesis and characterization of superoleophobic fumed alumina nanocomposite coated via the sol-gel process onto ceramic-based hollow fibre membrane for oil-water separation

Oily wastewater treatment is a global challenge due to the substantial amount of effluent resulted from many industrial and domestic activities. To overcome the challenge of using existing treatment approach and fouling, superoleophobic coatings were fabricated. In this study, a superoleophobic membrane surface was obtained using the sol-gel technique with perfluorooctanoate (PFO), poly (diallyl dimethylammonium chloride) (PDADMAC), and nanoparticles as complex-polymer nanocomposites. The effects of coating cycles on the surface structure, chemical properties, surface chemistry, and oleophobicity of the surface were examined using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and oil contact angle measurement. The results showed that the coated layer successfully adhered to the substrate surface. However, the chemical stability with respect to oil contact angle (OCA) revealed a decline at pH 7 and pH 9 and maintained stability at pH 3. Besides, oil flux at 63.0 L/m². h was achieved for PDADMAC-Al₂O₃/44 wt% PFO and the highest separation efficiency of 98% was obtained. Furthermore, the oil rejection decreases as the oil concentration increases from 1 to 3 g/L. OCA of 155° was obtained after 5 coating cycles. Apart from mitigating substrate fouling, the superoleophobic and superhydrophilic coating can be applied to a ceramic-based hollow fibre membrane and efficiently used for the separation of oil from oily wastewater.     

Preparation of PEDOT-modified double-layered hollow carbon spheres as Pt catalyst support for methanol oxidation

In this paper, Pt nanoparticles (Pt NPs) deposited hybrid carbon support is prepared by modifying double-layered hollow carbon spheres（DLHCs）with poly(3,4-ethylenedioxythiophene) (PEDOT) and used as anode catalyst of methanol oxidation. The structure of nanocomposites is characterized by SEM, TEM, FT-IR, XRD and XPS, confirming the greatly enhanced synergistic effect between the PEDOT and DLHCs, and illustrating the uniform distribution of Pt NPs on the PEDOT/DLHCs composite surface with a small particle size (~2.63 nm). Cyclic voltammetry, chronoamperometry and impedance spectroscopy applied to determine the electrocatalytic activity of catalysts, it is found that the synthesized PEDOT/DLHCs/Pt possesses excellent characteristics such as large electrochemically active surface area and high mass activity of 59.45 m² g⁻¹ and 807 mA mg⁻¹ in 0.5 M H₂SO₄ containing 1 M methanol solution, which is almost 1.24 and 2.8 times greater than those of commercial Pt/C, and the catalyst exhibits superior stability after 500 durability cycles. The enhanced electrocatalytic behavior can be ascribed to the excellent electronic conductivity of PEDOT-modified DLHCs and the strong binding of PEDOT/DLHCs to Pt NPs, suggesting that the PEDOT/DLHCs/Pt is a promising electrocatalyst for direct methanol fuel cell.     

Solution‐Processable Photonic Inks of Mie‐Resonant Hollow Carbon–Silica Nanospheres

Hollow carbon–silica nanospheres that exhibit angle‐independent structural color with high saturation and minimal absorption are made. Through scattering calculations, it is shown that the structural color arises from Mie resonances that are tuned precisely by varying the thickness of the shells. Since the color does not depend on the spatial arrangement of the particles, the coloration is angle independent and vibrant in powders and liquid suspensions. These properties make hollow carbon–silica nanospheres ideal for applications, and their potential in making flexible, angle‐independent films and 3D printed films is explored.     

Experimental investigations of enhanced glow based on a pulsed hollow-cathode discharge

In this work, the pulsed hollow cathode discharges at low pressure argon with an axial magnetic field were studied. The results indicate that the pulsed discharge is operated in an enhanced glow(EG) mode. Under the same conditions, the discharge current of the pulsed discharge is two or three orders higher than that of the direct current discharge. The spatial and temporal evolution of the light emission shows that, the current fluctuation at the rising edge of the pulse plays an important role for the EG discharge of pulsed hollow cathode, which forms a high-density, highcurrent and long-distance plasma column outside the cavity.     

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

The Fischer–Tropsch synthesis (FTS) continues to be an attractive alternative for producing a broad range of fuels and chemicals through the conversion of syngas (H₂ and CO), which can be derived from various sources, such as coal, natural gas, and biomass. Among iron carbides, Fe₂C, as an active phase, has barely been studied due to its thermodynamic instability. Here, we fabricated a series of Fe₂C embedded in hollow carbon sphere (HCS) catalysts. By varying the crystallization time, the shell thickness of the HCS was manipulated, which significantly influenced the catalytic performance in the FTS. To investigate the relationship between the geometric structure of the HCS and the physic-chemical properties of Fe species, transmission electron microscopy, X-ray diffraction, N₂ physical adsorption, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, Raman spectroscopy, and Mössbauer spectroscopy techniques were employed to characterize the catalysts before and after the reaction. Evidently, a suitable thickness of the carbon layer was beneficial for enhancing the catalytic activity in the FTS due to its high porosity, appropriate electronic environment, and relatively high Fe₂C content.     

SiO2气凝胶隔热保温涂料研究及保温结构优化设计

石油化工行业是国家节能减排重点工程之一，如果相关设备设施保温不当，不仅会造成严重的热量散失，还会对油水分离和输送等产生影响。本文系统介绍了传统的以中空玻璃微珠或陶瓷微珠为主要隔热功能填料的隔热保温涂料的保温机理、性能及其存在的问题；以 SiO₂气凝胶为主要功能填料的新型隔热保温涂料研究现状及研究中的技术难点；针对不同应用环境，开发兼具防腐、防开裂、隔热保温功能的复合保温结构设计。本文为研制新型耐高温、高效水性无机隔热保温涂料的研究提供了参考方向，为隔热保温涂料在石油化工领域的工程应用提供分析。     

Up-pulling force analysis for ESC hollow cylindrical casting

Electroslag casting(ESC)is an important method to produce high quality castings.In this study,the ESC up-pulling inner mold method(EUPIM)was used to produce hollow cylindrical castings with the multiple consumable electrodes.The radial deformation,the axial and radial internal stress of the inner mold,and the axial internal stress of the slag shell were analyzed using the finite element method(FEM)with the aid of ANSYS software.The ProCAST software was used to calculate the specific heat,heat conductivity and density curve of Cu.Simulation results show that the radial deformation,the axial and radial internal stress of the inner mold,and the axial internal stress of the slag shell near the slag-metal interface of hollow cylndrical casting gradually increase from 0 s to 360 s after the ESC starting(slagging)process but before applying the up-pulling force.The suitable initial up-pulling moment of the inner mold is at around 180-198 s after the starting process.     

基于SnO2中空纳米球的低温氢气传感器的研究

采用水热法一步合成SnO2纳米材料,采用XRD、SEM、TEM和氮吸附-脱附对材料的结构和形貌进行表征。表征结果表明所制备SnO2纳米材料是由直径150~200 nm的中空纳米球组成,且具有较大比表面积(82.6 m2/g)。采用丝网印刷技术将SnO2气敏浆料涂覆到叉指电极上,制成厚膜型气体传感器器件,研究其对氢气的气敏性能。结果表明SnO2中空纳米球在较低温度(200℃)下对5~200μl/L氢气具有较高的响应值及较快的响应速度,这归因于所制备的SnO2材料的中空结构和较大比表面积,利于氢气气体的吸附与扩散。