Characterization of nanoporous materials prepared from montmorillonite clay and its application to the decolorization of mare's milk oil

Nanoporous materials have been prepared by leaching the purified montmorillonite clay with sulfuric acid (H₂SO₄) solution with varying concentrations (0.5–2 M) at 80°C for 0.5–4 h. Acid leaching causes partial amorphisation of the clay with depletion of MgO, Al₂O₃, CaO and Fe₂O₃ components mostly from interlayer and octahedral sites. This increases the specific surface area by more than 3 times, i.e. from 49.1 to 157 m²/g. The pore-size distribution curves calculated from the adsorption isotherms of the leached montmorillonite show that most of the pores are in the mesoporous region with their diameter ranging 3–4 nm. This material turns out to be appropriate for bleaching of the mare's milk oil. The chemical and structural changes of the acid-leached montmorillonite are discussed in terms of the decolorization capacity.     

Fabrication of Porous SiC Ceramics with Special Morphologies by Sacrificing Template Method

Sacrificial template technique is widely used in producing porous materials with controlled morphologies and tailored properties. In this paper, unique templates such as filters, carbon nanotube, carbon fiber and silica were used to make porous SiC ceramic with special morphologies. Template derived porous ceramic plates, SiC nano-net, fiber-inverse and bead-inverse porous SiC ceramic were successfully prepared from the preceramic precursor, polymethylsilane (PMS). The synthesis procedures were involved with the infiltration of the templates with appropriate concentration of the preceramic polymer, their curing, pyrolysis and subsequent template removal. The synthesized porous SiC was characterized by SEM, TEM, XRD and BET methods.     

Dynamics of fluid circulation in coupled free and heterogeneous porous domains

Fluid flow in coupled free and porous domain, particularly when the porous medium is heterogeneous, is encountered in many hydro-environmental conditions, e.g., leakage from underground pipe, combined groundwater lake-subsurface interactions. One of the most difficult problems in the study of coupled flow behaviour has been the development of a universally applicable modelling scheme for combining the flow regimes. This is because the free/porous interfacial properties (e.g., shear-stress; velocity slip) that govern the coupled flow behaviour are difficult to determine experimentally under hydro-environmental conditions. On the other hand, the implications of various forms of heterogeneity in the porous media properties can be very different on the fluid-flow behaviour. Difficulties may also arise in direct coupling of the model equations that govern the fluid flow in the individual regions (e.g., Navier-Stokes for free-flow region and the Darcy's equation for the porous flow region). Consequently, models of coupled free and porous flow for hydro-environmental conditions are not very well developed at the moment. While there are some indications that fluids in coupled free and porous domains may circulate (i.e., development of flow cells), there is a lack of appropriate 3D analysis on how heterogeneities in porous media may affect such flow patterns. In this paper, we aim to analyse how porous media heterogeneity affects the dynamics of flow circulation in the porous side of a coupled free and porous domain. For this purpose, we analyse flow patterns in several model domains made up of two porous layers with differing permeabilities. The governing model equations are discretised and solved using the standard finite volume method on a staggered cell-centred mesh. The temporal discretisation is done using the explicit method. An in-house graphical user interface (GUI) has been created specifically to aid in the visualisation of otherwise complex flow patterns. The GUI contains many post-processing options and provides a comprehensive tool for the analysis of hydrodynamics and contaminant motion (not discussed in this paper) in coupled free and porous flow domains. This GUI is described in this paper briefly. The effects of altering the aspect ratio (i.e., multi-scale) of the domain on the coupled flow pattern have also been discussed.     

多孔陶瓷分离膜

多孔陶瓷膜由于其优良的耐高温、耐腐蚀、耐微生物侵蚀等性质，近年来被快速地应用于分离领域。本文介绍其制备方法、性能测定及应用前景。     

Surface hydrolysis of filaments based on poly(trimethylene terephthalate) spun at high spinning speeds

The surface alkaline hydrolysis of fibers made from poly(trimethylene terephthalate) (PTT) was studied after extruding the polymer at high spinning speeds from 2000 to 6000 m/min and heat setting in the range of temperatures from 100 to 180°C. Fiber weight loss increased with an increasing heat‐setting temperature but it was also dependent on the spinning speed. Some of the partially hydrolyzed fibers had a well‐developed, hydrophilic surface, and pore size in the range of 0.69 to 1.20 μm. The optimum reaction and morphological conditions for increasing porosity in PTT fibers depends on spinning speed and heat‐setting temperature. A temperature of 180°C is the upper limit for heat‐setting PTT filaments but seems to be the most effective for making porous fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1724–1730, 2004     

地下水多孔介质中胶体与污染物协同运移规律研究进展

在总结国内外地下水中污染物运移规律研究的基础上,阐述了地下水多孔介质中胶体与污染物协同运移的研究进展。讨论了胶体运移的基本过程、相关机理,探究污染物-胶体-微生物(生物胶体)协同运移的作用方式、影响因素、实验分析、模型构造,并指出该领域目前研究存在的主要问题,以及对该领域研究趋势的展望。     

多孔陶瓷材料的制备技术及应用

本文综述了近年来多孔陶瓷材料制备技术的研究现状及应用，多孔陶瓷性能特殊，应用广泛，并为生物医学等相关行业带来进步。     

纳米二氧化硅模板的制备

以微乳液法制备纳米二氧化硅（SiO2）粒子，经压制、烧结制备SiO2模板。通过红外（IR）、热分析（TGDTA）、扫描电镜（SEM）等方法对SiO2模板进行表征，结果表明所得SiO2粒度在100nm左右．烧结温度在800℃时，SiO2粒子之间将实现颈长，有利于有机／无机杂化多孔材料的制备。     

多孔β-TCP陶瓷药物载体结构与性能的影响因素

本分析了影响多孔β-TCP陶瓷药物载体结构与性能的因素，确定了制备多孔β-TCP陶瓷药物载体的技术路线和工艺参数。     

莫来石纤维多孔陶瓷负载性能研究

用酸性偏磷酸盐作粘结剂、加压排液法成型制备了孔隙率高达96％的莫来石纤维多孔陶瓷，采用真空浸渍法，对其负载稀土复合金属氧化物La0.8Sr0.2CoO3的性能进行了研究，考察了浸渍时间、浸渍次数对负载量的影响，得出最佳浸渍时间为60min，浸渍次数为2次。通过扫描电镜(SEM)表征了内部架构，最后指出莫来石纤维多孔陶瓷有望成为具有较好效果的新型催化剂载体。