新型中空纤维陶瓷膜的制备方法

新型中空纤维陶瓷膜由于具有装填密度大、单位体积膜有效分离面积大、膜壁薄、渗透通量高和节省原料等独特优点而受到广泛关注,在用于多孔和致密陶瓷分离膜、固体氧化物燃料电池、微通道反应器、催化剂载体等方面都有着潜在的应用前景。在概括中空纤维陶瓷膜特点的基础上,综述了中空纤维陶瓷膜的制备方法研究进展,着重分析比较了不同制备方法的优缺点。将相转化法应用于中空纤维陶瓷膜的制备,可实现通过一步成型制造具有自支撑非对称结构的复合陶瓷膜,有利于提高膜的渗透通量、简化膜制备工艺和显著降低制造成本。     

中空纤维陶瓷膜的研制现状与应用前景

相转化法制备中空纤维陶瓷膜是新近发展起来的一种陶瓷膜制造新工艺,它兼有了有机膜和无机膜制备方法的优点.中空纤维陶瓷膜具有比传统陶瓷膜比表面积大、自支撑体成膜、工艺简单和成本低等独特优势,因而在很多领域具有广泛的应用潜力和竞争力.本文主要介绍了利用高分子辅助方法制备如Al2O3、YSZ等中空纤维陶瓷膜的制备原理,研究进展及其在分离膜、质子导电膜、透氧膜和燃料电池等方面的应用现状.     

丙烯膜法脱水工艺技术的研究分析

传统的丙烯脱水工艺存在能耗高、丙烯浪费大、再生氦器气用量大等缺点。蒸汽渗透技术具有能耗低、过程简单、分离因子高、操作灵活等优点，而且它的渗透通量较低，这使得它特别适用于微量可凝组分的分离。本研究以脱除丙烯中微量水分为目的，以聚乙烯醇、壳聚糖为复合膜活性层，聚砜中空纤维膜为支撑层，制备出多种中空纤维复合膜。考察制膜条件及实验操作条件对膜性能的影响。     

聚醚砜分子量对相转化法YSZ中空纤维陶瓷膜结构与性能的影响

采用不同分子量聚醚砜(PES)作为聚合物结合剂,通过相转化法和高温烧结制备了非对称结构YSZ中空纤维陶瓷膜。研究了不同分子量聚醚砜制备的铸膜浆料粘度变化对相转化过程及膜的微观结构与孔隙率和孔径、纯水和氮气渗透通量及抗弯强度等性能的影响。结果表明,采用分子量较小的PES制备的中空纤维膜由内侧大指孔结构和外侧小指孔结构构成。随着PES分子量和铸膜浆料粘度提高,外侧指孔长大而内侧指孔减小,且出现明显的中间海绵层。随着浆料粘度提高,膜孔隙率明显下降。采用PES E3010作为聚合物原料时,制备的YSZ中空纤维膜具有最大的外表皮层分离孔径,表现出最高的渗透性能和抗弯强度,在1400℃保温3 h烧结时,膜纯水通量和抗弯强度分别可达到9.35 m~3/(m~2·h·MPa)和113.9 MPa。     

一种聚氯乙烯中空纤维超滤膜制备方法

本发明的目的是提供一种聚氯乙烯中空纤维超滤膜制备方法,用于制造、使用寿命长,膜丝断裂伸长率高、水通量大而且易清洗的聚氯乙烯中空纤维超滤膜。为达到所述效果,本发明一种聚氯乙烯中空纤维超滤膜制备方法,包括由以下重量百分比的组份的铸膜液制成：     

原料碳化硅种类及粒径对所制备中空纤维膜的影响

碳化硅中空纤维膜兼具碳化硅耐酸耐碱和中空纤维膜的比有效过滤面积大的优势。以不同碳化硅粉与炭黑、硅粉为主要原料,采用挤出成型和高温烧结的方法,制备出了碳化硅中空纤维膜,并对所制备样品的机械强度、孔隙率、孔径大小及分布、氮气通量等性能进行了测试。结果表明:碳化硅的种类对陶瓷纤维膜性能有较大影响,以绿碳化硅粉为原料制备的中空纤维膜其各项性能指标更优,所制备中空纤维膜具有高渗透性和窄孔径分布,并且随着碳化硅粉粒径的减小,所制备样品机械强度增大,开孔孔隙率、孔径以及氮气通量均减小。     

多孔堇青石中空纤维陶瓷膜的制备与表征(英文)

采用相转化和烧结法,通过一步成型制备了新颖的堇青石中空纤维陶瓷膜,并对制备的中空纤维膜微观结构、孔隙率和孔径分布、抗弯强度、纯净水通量和氮气渗透性等结构与性能进行了表征。结果表明:堇青石中空纤维膜为多孔非对称结构,由内部大孔层和外部海绵状多孔层组成。在1360℃保温2h制备的堇青石中空纤维膜孔隙率为39.2%,抗弯强度为76.5MPa。0.10MPa压差下的纯净水和氮气渗透性分别达到61.34m3/(m2·h·MPa)和7824m3/(m2·h·MPa)。实验证明,采用较大粒径的廉价工业级粉体为原料,可制备非对称的中空纤维陶瓷微滤膜。     

中空纤维陶瓷膜的制备及表面修饰

以YSZ粉末、聚醚砜(PES)、N,N-二甲基吡咯烷酮(NMP)为原料,聚乙烯吡咯烷酮(PVP)为添加剂,NMP与水的混合溶液为芯液,自来水为外凝固液,利用相转化法制备了中空纤维陶瓷膜,并研究了PVP质量、芯液组成、涂膜次数对中空纤维陶瓷膜结构和性能的影响。结果表明:随着PVP质量的增加,中空纤维陶瓷膜的抗弯强度逐渐增加,孔隙率与水通量逐渐减小;随着芯液中NMP质量分数的减小,膜的抗弯强度逐渐增强,其水通量和透气率逐渐减小,膜的管壁逐渐变厚;随着涂膜次数的增加,中空纤维陶瓷膜的抗弯强度随之增大,透气率随之减小,修饰层逐渐变厚,膜外表面的孔径和孔数逐渐减少,膜外表面变得越来越致密。     

相转化法制备氧化钇稳定氧化锆中空纤维陶瓷膜

采用相转化和烧结相结合的方法制备了氧化钇稳定氧化锆(YSZ)中空纤维陶瓷膜，研究了铸膜液中YSZ粉末含量和烧结温度对中空纤维陶瓷膜的微观结构和性能的影响。结果表明，YSZ中空纤维陶瓷膜的不对称结构包含指状结构和海绵状结构，YSZ含量会影响两种结构的比例，烧结则会引起微观结构的致密化。在铸膜液配比为m(YSZ):m(PSF):m(NMP)=5.0:1:4，烧结温度为1200 ℃的条件下制备出性能良好的中空纤维陶瓷膜，其纯水通量为2.33 m3/(m2·h·MPa)，抗弯强度为134.5 MPa。     

内压式中空纤维膜气体脱CO2应用研究

针对天然气、沼气、烟道气等脱CO_2应用需求,探究了内压式中空纤维膜的气体分离性能,考察了压力、温度、处理量等对膜分离性能的影响。结果显示,与外压式膜不同,随着压力的增加内压式中空纤维膜的气体渗透通量显著增加。压力越高对混合气的处理能力越大,且膜组件存在最优处理能力。随着温度的增加,渗透通量增加、分离系数下降。     

Development of high strength,porous mullite ceramic hollow fiber membrane for treatment of oily wastewater

Ceramic hollow fiber membranes (CHFMs) are known for their excellent characteristics including high surface area, compact design, and good chemical, thermal, and mechanical stabilities. Despite these interesting attributes, CHFMs are also prone to certain limitations, such as brittleness and high cost that hinder them from being commercialized. To mitigate this drawback, we have developed a high strength, porous ceramic hollow fiber membrane, derived from mullite–kaolinite powder, for efficient oil–wastewater separation. The superhydrophilic, low-cost mullite-based (CHFM) was successfully fabricated through combined phase inversion and sintering techniques. Prior to the fabrication, the as-received mullite–kaolinite was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analyses. Subsequently, operational parameters such as the effect of mullite content, sintering temperature, and air gap were optimized during the fabrication of mullite ceramic hollow fiber membrane. The resulting membranes were systematically characterized and evaluated in terms of morphology, porosity, mechanical strength, water flux, and oil–water separation. Increasing the mullite content, air gap, and sintering temperature enhanced the formation of microvoid structure. It is interesting to note that the mechanical strength of 86 MPa was obtained for the membrane containing 60 wt % of mullite sintered at 1450 °C and an air gap of 5 cm. The membrane induced a stable permeate water flux and oil rejection of mullite CHFM of 182 L/m²?h and 97.1%, respectively. As compared to kaolin ceramic counterparts, this porous mullite ceramic hollow fiber membrane can be used in various water treatment applications, including for the separation of oily wastewater due to its mechanical strength and water flux.     

Zwitterionic monolayer grafted ceramic membrane with an antifouling performance for the efficient oil-water separation

Enormous demands on the separation of oil/water (O/W) emulsions in various industries, such as petrochemical, food and pharmaceutical industries, are looking for high performance and energy-efficient separation methods. Ceramic membranes have been used to deal with O/W emulsions, for its outstanding characteristics of easy-operation, high-flux, and long-term stability. However, membrane fouling is still a challenge in the industrial application of ceramic membranes. Herein, antifouling ceramic membranes were fabricated by grafting zwitterions on the membrane surface via an environment-friendly two-step grafting method, which improves the antifouling property and permeability. Successful grafting of such zwitterion on the ceramic surface was assessed by the combination of FTIR and XPS characterization. More importantly, the hydration can be formed by electrostatic interactions layer on the modified membrane, which was confirmed by TGA characterization. The antifouling performance of prepared zwitterionic ceramic membranes in the separation of O/W emulsions was systematically tested. The results suggested that zwitterion can significantly improve the flux of ceramic ultrafiltration membrane, and can also improve antifouling property dramatically by reducing the irreversible fouling in the separation of O/W emulsions. Therefore, zwitterionic ceramic membranes hold promising potentials as an antifouling, highly efficient and green method in the practical purification of the O/W emulsions.     

低成本多孔非对称陶瓷过滤膜的制备与性能研究进展

陶瓷膜因具有机械强度高、耐高温、化学稳定性好、孔径分布可控、再生性能好和环境友好等诸多优势而被应用于众多行业。然而,其生产成本较高导致市场占有率低。此外,陶瓷膜还面临高渗透性和高选择性不能兼备的难题,这限制了其大规模应用。本文综述了采用廉价原料、添加烧结助剂和优化制备工艺来降低非对称陶瓷膜生产成本以及提高其性能方面的研究,分析了相关措施对陶瓷膜的利弊,并展望了陶瓷膜未来的发展方向和应用前景。     

陶瓷纳滤膜制备与应用研究进展

陶瓷纳滤膜以其优良的热稳定性、化学稳定性和机械强度等特性,在涉及高温、酸碱、有机溶剂等苛刻环境的过程工业领域具有广阔的应用前景。因此,陶瓷纳滤膜材料的制备研究已引起众多科研工作者的关注。本文综述了陶瓷纳滤膜在制备及应用方面的研究进展,着重介绍了溶胶-凝胶法、化学气相沉积法、原子层沉积法及表面接枝等陶瓷纳滤膜制备方法。溶胶-凝胶法反应温度低、操作过程相对简单且精确可控,是目前国内外陶瓷纳滤膜制备的常用方法;化学气相沉积法及原子层沉积法则需借助气相化学反应在多孔基底表面进行材料沉积,从而修复缺陷,减小平均孔经;表面接枝技术可改变陶瓷膜表面亲疏水性,同时将陶瓷基膜孔径减小至纳滤范围。此外简单介绍了陶瓷纳滤膜的应用,并对未来陶瓷纳滤膜研究方向提出了建议,指出陶瓷纳滤膜微结构参数与分离性能之间的关系建立,以及探讨陶瓷纳滤膜在溶剂体系中的分离机理将成为今后一段时间内的研究热点。     

Influence of sintering temperature on the morphology of ceramic hollow fibers prepared from niobium pentoxide

Ceramic hollow fibers were prepared by the phase inversion and sintering method using niobium pentoxide (Nb₂O₅) as an innovative starting material. X-ray diffraction and Raman analyses revealed the same monoclinic crystalline phase for the ceramic material, H-Nb₂O₅, at all the evaluated sintering temperatures. According to SEM images, the starting material was composed of polydisperse particles of irregular size and shape with sizes ranging from 12.5 to 89.7 μm. The increase in the sintering temperature caused particles agglomeration. In the hollow fiber precursor (without sintering), Nb₂O₅ grains were surrounded by the coagulated polymer. The polymeric phase was eliminated when the fibers were sintered at temperatures above 600°C. When sintered at 1350°C, the outer surface of the fiber presented elongated crystals of well-defined shape, while agglomerated round shape grains were observed at the inner surface of the fiber. Formation of these elongated crystals was probable due to the material sintering at high temperatures (up to 1350°C) for more than 300 minutes. This study demonstrated the potential for general applicability of niobium pentoxide to fabricate ceramic hollow fiber membranes.     

中空纤维膜制备方法研究进展

介绍了中空纤维膜3种主要制备方法,即溶液纺丝法、熔融纺丝-拉仲法和热致相分离法。分别阐述了这3种方法的技术路线和致孔机理,回顾了3者的进展,展望了中空纤维膜制备技术的发展趋势。     

Fabrication of polysulfone asymmetric hollow‐fiber membranes by coextrusion through a triple‐orifice spinneret

Polysulfone (PSf) asymmetric hollow‐fiber membranes, which have a dense outer layer but a loose inner layer, were tentatively fabricated by coextrusion through a triple‐orifice spinneret and a dry/wet‐phase inversion process. Two simple polymer dopes were tailored, respectively, for the dense outer layer and the porous inner layer according to the principles of the phase‐inversion process. By adjusting the ratio of the inner/outer extrusion rate, the hollow‐fiber membranes with various thicknesses of outer layers were achieved. The morphology of the hollow‐fiber membranes was exhibited and the processing conditions and the water permeability of the membrane were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 259–266, 2004     

Effect of stretching on continuous oil/water separation performance of polypropylene hollow fiber membrane

In this work, polypropylene (PP) hollow fiber membranes were fabricated by thermal-induced phase separation method. The influence of cold-stretched and hot-stretched treatment on the morphology and permeability of the PP hollow fiber membranes was investigated. The results showed that there were cracks and crystalline particulate structures on the outer and inner surfaces of the stretched PP hollow fiber membranes, which were not isolated but linked together through fiber-like connections. Compared to the original PP hollow fiber membrane, the mean pore sizes, the porosities, the hydrophobicity and water entry pressure of the stretched PP hollow fiber membranes improved significantly. When applied in conjunction with a vacuum system, the PP hollow fiber membranes could continuously remove oils from water surface, and separate surfactant-free and surfactant-stabilized water-in-oil emulsions, as well. The initial kerosene fluxes of the hot-stretched PP hollow fiber membrane were higher than that of the membranes prepared from original PP hollow fibers or cold-stretched PP hollow fibers. The permeate fluxes of the hot-stretched PP hollow fiber membrane for all different emulsion separations were higher than those of the original PP hollow fiber membrane. There could be seen no emulsion droplet in the optical micrographs after separation, indicating that the water-in-oil emulsions were effectively separated in one-step method.     

Hollow fiber nanofiltration membranes: A comparative review of interfacial polymerization and phase inversion fabrication methods

Membrane-based separation is now established as one of staple technologies used in water treatment and reuse applications. Nanofiltration, in particular, can be a cost-effective solution for removing large ions and low-molecular-weight compounds from water. Nanofiltration membranes have been manufactured mostly as flat sheets and used in spiral wound modules. Hollow fiber geometry, however, offers several advantages over flat sheet and other configurations. This paper overviews recent developments in the design of hollow fiber nanofiltration membranes and provides a comparative analysis of two main methods of their fabrication: interfacial polymerization and phase inversion.     

Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes for pervaporation separation of ethanol/water solution

Polysulfone (PSF) hollow fiber membranes were spun by phase‐inversion method from 29 wt % solids of 29 : 65 : 6 PSF/NMP/glycerol and 29 : 64 : 7 PSF/DMAc/glycol using 93.5 : 6.5 NMP/water and 94.5 : 5.5 DMAc/water as bore fluids, respectively, while the external coagulant was water. Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes were prepared after PSF hollow fiber membranes were coated using different PVA aqueous solutions, which were composed of PVA, fatty alcohol polyoxyethylene ether (AEO₉), maleic acid (MAC), and water. Two coating methods (dip coating and vacuum coating) and different heat treatments were discussed. The effects of hollow fiber membrane treatment methods, membrane structures, ethanol solution temperatures, and MAC/PVA ratios on the pervaporation performance of 95 wt % ethanol/water solution were studied. Using the vacuum‐coating method, the suitable MAC/PVA ratio was 0.3 for the preparation of PVA/PSF hollow fiber composite membrane with the sponge‐like membrane structure. Its pervaporation performance was as follows: separation factor (α) was 185 while permeation flux (J) was 30g/m²·h at 50°C. Based on the experimental results, it was found that separation factor (α) of PVA/PSF composite membrane with single finger‐void membrane structure was higher than that with the sponge‐like membrane structure. Therefore, single finger‐void membrane structure as the supported membrane was more suitable than sponge‐like membrane structure for the preparation of PVA/PSF hollow fiber composite membrane. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 247–254, 2005