活性污泥对管式多孔α-Al_2O_3陶瓷膜支撑体性能影响的初步研究

以剩余活性污泥作为支撑体的成孔剂,采用滚压成型及熔膜芯法制备管状多孔α-Al2O3陶瓷膜支撑体,研究了粘结剂羧甲基纤维素(CMC)和活性污泥的加入量对氧化铝陶瓷膜支撑体品质的影响。结果表明,随着成孔剂和粘结剂的增多,支撑体孔隙率和渗透通量呈增大趋势,孔隙率最大可达43.07%,纯水通量在0.4~1.0 MPa压力下变化范围为12 786.67~37 617.84 L/(m2·h·MPa)。     

活性污泥对管式多孔α-Al_2O_3陶瓷膜支撑体性能影响的初步研究

以剩余活性污泥作为支撑体的成孔剂,采用滚压成型及熔膜芯法制备管状多孔α-Al2O3陶瓷膜支撑体,研究了粘结剂羧甲基纤维素（CMC）和活性污泥的加入量对氧化铝陶瓷膜支撑体品质的影响。结果表明,随着成孔剂和粘结剂的增多,支撑体孔隙率和渗透通量呈增大趋势,孔隙率最大可达43.07%,纯水通量在0.4~1.0 MPa压力下变化范围为12 786.67~37 617.84 L/（m2·h·MPa）。     

Preparation and investigation of porous aluminosilicate ceramic materials

The optimum conditions for the synthesis of macroporous aluminosilicate ceramic materials are chosen. The dependence of the total porosity of the ceramic materials on the initial components is established. The pore size distribution is investigated. The chemical durability of the ceramic materials is determined.     

催化型多孔陶瓷球制备及催化玉米秸秆热解

针对生物质热解液化过程中生物油品质差的问题,本文以陶瓷球作热载体为研究基础,制备了5种负载金属氧化物（ZnO、NiO、CeO₂、Cr₂O₃、Fe₂O₃）的多孔陶瓷球,在固定床反应器上研究多孔陶瓷球催化剂对玉米秸秆热解过程的催化效果。结果表明：多孔陶瓷球基体在热解过程中有一定催化活性,经浸渍改性处理后,都能促进生物油产率的提高,其中Ni基多孔陶瓷球热解的产率高达41.62%。多孔陶瓷球负载的5种金属氧化物可促使生物油中酚类、呋喃类物质的含量明显增加,酸类物质的含量明显降低,且种类减少,其中CeO₂降酸效果显著,降低幅度为37.15%。此外,催化型多孔陶瓷球的引入促进了不可冷凝气中C _n H _m （n≥2）的生成,烯烃类中乙烯的增长幅度最大,为50.53%,同时生物炭的理化特性在一定程度上得到改善和提高。     

耐溶剂聚酰亚胺/陶瓷复合膜的制备及性能表征

采用3,3',4,4'-二苯酮四羧酸二酐(BTDA)、4,4'-二氨基二苯基甲烷(MDA)和4,4'-二氨基联苯(Bz)按一定比例共聚合成了一类新的共聚型聚酰亚胺(PI-BTDA/MDA/Bz),通过调整MDA和Bz的比例制备了4种具有不同化学结构的聚酰亚胺均质膜,测试了这些聚酰亚胺均质膜对水的接触角和在N,N-二甲基甲酰胺中的溶胀性。实验结果表明:BTDA、MDA、Bz的摩尔比为5:4:1时,所得的聚酰亚胺均质膜亲水性最好,且耐溶剂性能最优。以此比例的聚酰胺酸为铸膜液,0.2mm孔径的Al₂O₃陶瓷膜片为支撑体,制备了聚酰亚胺复合膜,并考察了进料温度和进料浓度对复合膜分离性能的影响。     

Strength degradation and failure limits of dense and porous ceramic membrane materials

Thin dense membrane layers, mechanically supported by porous substrates, are considered as the most efficient designs for oxygen supply units used in Oxy-fuel processes and membrane reactors. Based on the favorable permeation properties and chemical stability, several materials were suggested as promising membrane and substrate materials: Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3?δ, La_0.6?xSr_0.4Co_0.2Fe_0.8O_3?δ (x = 0, 0.02) and Ce_0.9Gd_0.1O_1.95?δ. Although membranes operate at elevated temperatures, the ends of tubes in certain three-end concepts remain almost at room temperature. The current work concentrates on the failure potential of these membrane parts, where in a complex device also the highest residual stresses should arise due to differences in thermal expansion. In particular, sensitivity of the materials to subcritical crack growth was assessed since the long-term reliability of the component does not only depend on its initial strength, but also on strength degradation effects. The results were subsequently used as a basis for a strength–probability–time lifetime prediction.     

Preparation and characterization of PSSA/PVA catalytic membrane for biodiesel production

Poly(styrene sulfonic acid) (PSSA)/Poly(vinyl alcohol) (PVA) blend membranes prepared by the solution casting were employed as heterogeneous acid catalysts for biodiesel production from acidic oil obtained from waste cooking oil (WCO). The membranes were annealed at different temperature in order to enhance their stability. The structure and properties of the membranes were investigated by means of Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), X-ray diffraction (XRD). It is found that the crosslinking structure among PVA and PSSA chains formed when the thermal treatment temperature was higher than 80 °C. The retention of PSSA in the blend membranes in the methanol/water solvent was markedly increased from 50% to 85% with the increase of the annealing temperature from room temperature (for the untreated membrane) to 150 °C due to the formation of the crosslinking structure. The results of esterification of acidic oil show that the conversion was slightly improve with the PVA content in the membrane at a fixed PSSA content. The thickness of the catalytic membrane had no significant effect on the conversion in the end. The membrane annealed at 120 °C exhibited the best catalytic performance among the membranes, with a stable conversion of 80% with the runs.     

Preparation of porous ceramic materials based on wollastonite using silicon-containing components

Results are provided for evaluation of the possibility of preparing porous ceramic materials using synthetic wollastonite and silicon-containing components by chemical pore formation. The mechanism of pore formation, and also chemical processes during material drying and firing are studied. The physicochemical properties and microstructure of the material obtained are studied.     

Preparation and characterization of novel ceramic membranes for micro-filtration applications

Porous microfiltration range ceramic membranes were prepared using kaolin and other suitable materials like feldspar, quartz, boric acid, activated carbon, sodium metasilicate and titanium dioxide following standard paste casting route. The membranes were casted as circular disks of 40 mm ID and 5 mm thickness. They were characterized using thermo gravimetric analysis (TGA), particle size distribution (PSD), X-ray diffraction (XRD) and scanning electron microscope (SEM) to evaluate the effect of maximum sintering temperature on the structure, porosity and mechanical integrity. The prepared membranes were initially dried at 120 °C and 250 °C for 24 h each and finally sintered at 850 °C, 900 °C and 950 °C for 6 h. Morphological parameters viz. pore size distribution, porosity, average pore size of the prepared membranes were determined and the membrane performance were evaluated by carrying out the permeation experiment with pure water. Results show that the average pore size of the membranes increases from 1.59 µm to 2.56 µm and porosity of the membrane supports decreases from 18.88% to 5.59% with increase in sintering temperature from 850 °C to 950 °C. The membrane corrosion resistance was also tested using acid and base and it is observed that there is no significant weight loss in the process. Based on market price of the inorganic precursors, the membrane cost was estimated to be $92/m² which can be considered low cost in the microfiltration range for industrial applications.     

Preparation and characterization of porous,biomorphic SiC ceramic with hybrid pore structure

Bio-carbon template (charcoal) was prepared by carbonizing pine wood at 1200 °C under vacuum, and was impregnated with phenolic resin/SiO₂ sol mixture by vacuum/pressure processing. Porous SiC ceramics with hybrid pore structure, a combination of tubular pores and network SiC struts in the tubular pores, were fabricated via sol–gel conversion, carbonization and carbothermal reduction reaction at elevated temperatures in Ar atmosphere. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were employed to characterize the phase identification and microstructural changes during the C/SiO₂ composites-to-porous SiC ceramic conversion. Experimental results show that the density of C/SiO₂ composite increases with the number of impregnation procedure, and increases from 0.32 g cm⁻³ of pine-derived charcoal to 1.5 g cm⁻³ of C/SiO₂ composite after the sixth impregnation. The conversion degree of charcoal to porous SiC ceramic increases as reaction time is lengthened. The resulting SiC ceramic consists of β-SiC with a small amount of α-SiC. The conversion from pine charcoal to porous SiC ceramic with hybrid pore structure improves bending strength from 16.4 to 42.2 MPa, and decreases porosity from 76.1% to 48.3%.     

漫谈多孔陶瓷材料及其过滤技术

多孔陶瓷作为过滤元件组成的陶瓷过滤器,在各行业的分离,净化领域中已得到较全面的推广应用。陶瓷过滤器以其独特的功能特性,在各分离,净化领域中已成为一种不可替代产品。根据多孔陶瓷滤材技术的发展变迁,研究了多孔金属滤材与多孔陶瓷滤材的性能优势,阐述了多孔陶瓷滤材过滤元件的性能指标及过滤原理,介绍了多孔陶瓷及过滤器的应用市场,...     

Structural parameters of porous monodisperse ceramic materials

A method for determining the parameters of the porous structure of ceramic materials made from monodisperse particles and fibers that makes it possible to allow for the difference in the sizes of the interparticle and interfiber contacts is suggested. Analytical dependences for determining the coordination number of fiber systems as a function of the porosity and the size of the interfiber contacts are obtained. Examples of calculations are presented. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 15–18, February, 2000.     

Preparation and characterization of ceramic nanofiltration membrane prepared from hazardous industrial waste

Kiln rollers, which are widely used in ceramic tiles production, are usually subjected to surface grinding to remove the contaminations. The resulted fine powder is considered useless waste and a hazardous source of environmental pollution particularly as it contains health-threatening fine free silica. In the present paper, the grind waste from kiln rollers was reused as raw material in the fabrication of nanofiltration ceramic membrane. The samples of produced ceramic membranes were formed into disks by adding 15% (by weight) organic binder solution with 2% concentration, then pressed at 35 MPa, dried and fired at temperatures range from 1100°C to 1300°C for 1 hour soaking time. It was found that the best firing temperature to produce nanofiltration ceramic membrane is 1250°C, where the ceramic membrane provides high removal of turbidity and high monovalent, divalent, and trivalent salts separation percentage.     

磷钨酸/磺化聚醚砜/聚酯非织造布复合膜制备、表征及催化酯化性能

针对催化酯化反应中,传统的强酸、强碱催化剂会导致设备腐蚀严重,产生大量的废酸和废碱,造成环境污染等问题,采用溶液相转化法以聚酯非织造布(NWF)为支撑材料,磷钨酸(HPW)/磺化聚醚砜(SPES)为铸膜液,制备HPW/SPES/NWF复合催化膜。并对复合催化膜结构采用场发射扫描电镜(FESEM)、压汞仪和透射电镜(TEM)进行表征。研究了复合膜结构与性能之间的关系,考察了HPW加入量、进料流速、醇油质量比对酯化性能的影响以及复合膜重复使用性。结果表明,FESEM观察复合膜为均一的海绵状结构。压汞仪得到复合膜的平均孔径在60μm左右,孔隙率为65%。TEM得到HPW均匀地分散在SPES中。在最佳实验条件下,HPW/SPES/NWF复合催化膜转化率达到96.32%,重复使用5次转化率仍保持在96.03%。     

Preparation and characterization of multicomponent porous materials prepared by the sol-gel process

An experimental strategy was developed to obtain transparent Si-Al-Ti-Ni-Mo and Si-Zr-Ti-Ni-Mo sols via the sol-gel process. The sol was prepared from Si(OEt)₄ (TEOS), Al(OBu^s)₃ (OBu^s: C₂H₅CH(CH₃)O), Ti(OEt)₄ (OEt: OCH₂CH₃), Zr(OPrⁿ)₄ (OPrⁿ: OCH₂CH₂CH₃). In both cases nickel nitrate hexahydrate (Ni(NO₃)₂ · 6H₂O) and ammonium heptamolybdate tetrahydrate ((NH₄)₆Mo₇O₂₄ · 4H₂O) were the Ni and Mo sources, respectively. The sols were characterized by Fourier Transform Infrared Spectroscopy (FTIR). Assignments of the simultaneous formation of the Si-O-Al, Si-O-Ti, Si-O-Ni, and Si-O-Zr bonds were done. The sols were polymerized at room temperature (293 K) to obtain gels, and these were dried at 423 K and calcined at 573, 853 and 893 K in air. The characterization techniques used were small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and ²⁹Si and ²⁷Al magic angle spinning nuclear magnetic resonance (MAS NMR). The density of the solids was measured following ASTM method D-4892 and the porosity and surface area were determined by N₂ adsorption/desorption isotherms. The corresponding average pore diameters were evaluated using the BJH, HK, and DA methods.     

Preparation and characterization of red mud sintered porous materials for water defluoridation

This research was undertaken to characterize a porous material prepared from red mud and to investigate the capacity of zirconium hydroxide-modified red mud porous materials (Zr-modified RMPMs) for the removal of fluoride from aqueous solutions. An organic foam template was used for the preparation. After sintering, the RMPM had a porosity up to 80 % with the pore size controlled between 50 and 100 μm. Batch experiments were performed to study the defluoridation of water using Zr-modified RMPM under various experimental conditions. Kinetic data revealed that the equilibrium for fluoride removal was achieved within 60 min. The fluoride sorption process was well fitted to the pseudo-second-order rate kinetics and pore diffusion models. The optimum fluoride removal was observed between pH range 3 and 4 and the adsorption capacity for fluoride by Zr-modified RMPM was 0.6 mg/g. Results from this study demonstrated potential use of Zr-modified RMPM in defluoridation of drinking water.     

双金属氰化物络合物催化剂的制备、表征与催化性能研究

分别以PEG-1000、β-环糊精和吐温-60等为助络合剂,采用不同工艺方法制备了具有不同结构的双金属氰化物络合物(DMC)催化剂,研究了不同助络合剂和不同制备方法对DMC催化剂的形貌、粒径、晶型结构和催化活性的影响.结果表明以PEG-1000、β-环糊精和吐温-60等为助络合剂,利用传统制备方法可以获得晶态与非晶态组分混合物的DMC催化剂.而将助络合剂提前加入到钾盐和锌盐溶液中,可制备出高度分散的非晶态的DMC.这种非晶态的DMC催化剂活性高,反应速度快,其催化性能明显优于利用传统制备方法制备的DMC.     

Mechanical aspects of ceramic membrane materials

Interest in ceramic transport membrane materials has increased significantly leading also to questions with respect to mechanical reliability and robustness, hence, requiring knowledge of the mechanical properties. The current review focuses on the mechanical properties of such ceramics, emphasizing in particular relationships between mechanical properties, non-elastic effects, phase changes and materials’ stability. Room and elevated temperature application is considered with a main emphasis on elastic and creep deformation as well as fracture. Consideration is given to dense membranes as well as porous substrate materials for advanced asymmetric concepts. Properties are summarized for selected oxygen and proton conductors. Furthermore, mechanical properties of some selected porous ceramic and metallic substrate materials are given. In addition to the failure probability associated with the Weibull distribution of fracture stresses, creep rupture of dense materials and enhanced creep deformation of porous materials are aspects that need special consideration in the application of these materials in gas separation systems.