中空纤维陶瓷膜的研究进展

由陶瓷材料制备的无机膜具有良好的耐溶剂腐蚀性以及稳定性,在苛刻条件下能够表现出明显优于有机聚合物膜的性能。对陶瓷中空纤维膜的制备方法和制备过程中的相形成机理进行了讨论;从膜材料角度对其分类介绍;此外,介绍了陶瓷膜的煅烧工艺、表面改性及其应用等。     

Recent advances in acid-resistant zeolite T membranes for dehydration of organics

Zeolite membranes offer outstanding potentials in separation of many molecular mixtures due to their molecular sieving selectivity and the high thermal and mechanical stability that allow them to operate at harsh conditions.Development of durable and high separation performance membranes with lower fabrication and operation cost are highly demanded for industrial applications. Zeolite T membrane possesses good acid-resistance with excellent hydrophilic properties as compared to NaA zeolite membrane and can be extended to industrial organic dehydrations under an acidic environment. In the present review the research advances in development of zeolite T membranes for the dehydration of organic mixtures in acidic conditions are summarized. Especially the low temperature synthesis, and epitaxial growth of the zeolite membrane with high performance are well addressed, besides emphasis is particularly placed on ensemble synthesis of hollow fiber zeolite T membrane module and its future prospects for industrial separations.     

Mass transfer model,preparation and applications of zeolite membranes for pervaporation dehydration:A review

Pervaporation (including vapor permeation) is a kind of new membrane separation technology, possessing the advantages of high efficiency, energy saving and convenient operation. It has promising application in the separation and purification of organic solvents. Dehydration is an important step in the production and recovery of organic solvents. Zeolite membranes have attracted wide attention for pervaporation dehydration due to their high separation performance and good thermal/chemical stability. So far, zeolite membranes have been preliminarily industrialized for dehydration of organic solvents. This paper reviews the recent development of zeolitemembranes for pervaporation dehydration, includingmass transfermodels, preparation and applications of zeolite membranes. The review also discusses the current industrial applications of zeolite membranes and their future development in pervaporation.     

SRNF membranes for edible oil purification: Introducing free amines in crosslinked PEEK to increase membrane hydrophilicity

PEEK membranes with good stability in polar aprotic solvents are developed for the separation of edible oils from acetone. PEEK membranes are hydrophobic in nature, and thus suitable to achieve high fluxes in organic solvents. Chemical crosslinking with amines provides the membranes with robust solvent stability. In this research, three types of modified PEEK were synthesized. All were crosslinked with both the well-known difunctional crosslinker hexanediamine as with the multifunctional polyallylamine. Performance of membranes prepared with both crosslinkers was compared for rose Bengal solutions in isopropanol and acetone, and for sunflower oil dissolved in acetone. Using polyallylamine as a crosslinker introduced free amines into the membrane structure, increasing the hydrophilicity of the membrane which improved the retention of edible oil significantly.     

Evolution of polymeric hollow fibers as sustainable technologies: Past, present, and future

Energy, water, affordable healthcare and global warming are four major global concerns resulting from resource depletion, record high oil prices, clean water shortages, high costs of pharmaceuticals, and changing climate conditions. Among many potential solutions, advances in membrane technology afford direct, effective and feasible approaches to solve these sophisticated issues. Membrane technology encompasses numerous technology areas including materials science and engineering, chemistry and chemical engineering, separation and purification phenomena, molecular simulation, as well as process and product design. Currently, polymeric hollow fiber membranes made using a non-solvent-induced phase inversion process are the dominant products because polymers offer a broad spectrum of materials chemistry and result in membranes with desirable physicochemical properties for diverse applications. Their low cost and ease of fabrication make polymeric membranes superior to inorganic membranes. Therefore, this review focuses on state-of-the-art polymeric hollow fiber membranes made from non-solvent-induced phase inversion and the potential of membrane processes for sustainable water and energy production. The specific topics include: (i) basic principles of hollow fiber membrane formation and the phase inversion process; (ii) membranes for energy (natural gas, H₂, and biofuel) production; (iii) membranes for CO₂ capture; and (iv) emerging desalination technologies (forward osmosis and membrane distillation) for water production. Finally, future opportunities and challenges for the development of advanced membrane structures are discussed.     

Membranes for Kraft black liquor concentration and chemical recovery: Current progress,challenges, and opportunities

Membranes can significantly reduce energy consumption during concentration of black liquor (BL) in the Kraft papermaking process, but the harsh conditions (pH ~12, 80°C–95°C, ~15 wt% solids) make this challenging. We elucidate challenges and opportunities for membranes in BL applications. We critically review membrane materials, processes, and operational modes investigated in the literature. Future advances will involve fabrication of higher-rejecting (≥95% lignin and inorganics), BL-resistant, NF, and RO membranes. Opportunities exist for molecular sieving and electrically driven membranes to recover other valuable chemicals such as carboxylic acids. We also discuss the economics of BL concentration with a single-stage membrane process.     

金属有机骨架膜的制备与应用进展

膜分离技术因其高效节能的特点,被认为是最有前景的分离技术之一。由于众多待分离的混合组分在物理性质（如尺寸）上极为接近,实现精确的膜分离仍具有极大的挑战。金属有机骨架材料具有孔径精确可调、孔隙率高等优点,使其有望实现对尺寸相近分子的精确筛分,因此可以作为理想的膜材料。本文对传统的多孔膜材料进行了比较,并对基于金属有机骨架材料的多孔膜进行了分类,包括支撑型金属有机骨架膜和混合基质膜。同时,系统地总结了两大类金属有机骨架膜的制备方法及其发展历程,对先进的膜制备技术进行了展望;总结了金属有机骨架膜在气体分离、纳滤及海水淡化、渗透汽化等方面的应用。最后,针对支撑型金属有机骨架膜提出了改善其透量和选择性的思路。     

共混改性法对有机分离膜影响进展

有机聚合物如聚砜类、聚偏氟乙烯类、醋酸纤维素类、聚烯烃类等具有优良特性,是重要的膜材料。然而,膜污染问题限制了膜的应用。共混改性法操作简单,改性和成膜同时进行,效果稳定,通过共混改性法对有机聚合物膜进行膜改性可以有效降低膜污染。一方面通过共混亲水性聚合物、两亲性聚合物、两性离子聚合物对有机聚合物膜进行膜改性,制备改性膜的防污性和渗透性等性能均有不同程度的提升;另一方面,共混如TiO₂、SiO₂、碳纳米管（CNTs）、Al₂O₃、氧化石墨烯（GO）和ZrO₂等无机纳米粒子也可以制备高性能分离膜。本文从以上两方面综述了共混改性法的研究进展和存在的问题,并指出了通过共混改性提升膜的抗污染等性能是今后主要的发展趋势。     

Bottlenecks and recent improvement strategies of ceramic membranes in membrane distillation applications: A review

Ceramic membranes have received more attention currently from researchers in membrane distillation (MD) applications due to their outstanding properties. However, despite their superior mechanical, thermochemical stability, and resistance to harsh operating conditions, several bottlenecks still limit their applications in MD. Although there are several published articles on ceramic membranes in MD, the uniqueness of this review lies in the fact that it discusses the critical bottlenecks that significantly affect the performance of ceramic membranes in long-term operation and limit their scale-up to commercial MD applications. Furthermore, recent advances, strategies, and techniques to mitigate these limitations have also been discussed. A discussion on high ceramic membrane fabrication costs and mitigation strategies using alternative low-cost ceramic materials to erstwhile conventional ceramic materials has been presented. In addition, the inherent problems of the brittleness and wetting/fouling of ceramic membranes and recent advances in strengthening ceramic membranes and fouling/wetting control via the development of superhydrophobic and omniphobic ceramic surfaces in MD have been addressed. Consequently, technical bottlenecks that still exist despite recent development in ceramic membranes for MD applications have been highlighted and future research direction in developing robust ceramic membranes in MD applications has been elaborated.     

Advancement in separation materials for blood purification therapy

Blood purification refers to the extra corporeal therapies of removing potentially toxic substances, in which blood is circulated through an adsorption system loading separation materials. High-efficient inexpensive separation materials are critical to success. In this review, separation materials such as polymers and nanomaterials are summarized and compared. Combining the advantages of the adsorptive membranes and nanomaterials, organic–inorganic hybrid/blend membranes have been developed explosively. These hybrid/blend membranes have both the characteristics of high permeability, easy fabrication, good biocompatibility of adsorptive membranes, and characteristics of fast adsorption rate and high adsorption capacity of nanomaterials. The preparation and modification methodology of the separation materials is reviewed. For affinity separation materials, the relationship of ligand chemistry, ligand density and pores of the matrix is discussed. This paper also summarizes some interesting applications in separation materials for removal of bilirubin, endotoxin, toxic metal ions, cytokine, etc.     

Recent progress on low-cost ceramic membrane for water and wastewater treatment

Great progress in the development of low-cost ceramic membranes from alternative materials have been achieved recently towards various application especially water and wastewater treatment. However, their significance has not been fully recognized and understood especially in term of their microstructural analysis such as formation of grain growth and microcracks. This review paper summarizes fabrication method, alternative materials, microstructure, wettability, mechanical properties and application of low-cost ceramic membrane. The fabrication method including slip casting, tape casting, extrusion, pressing method and phase inversion technique are described. Alternative materials used in low-cost ceramic membrane fabrication are discussed and categorized into clays, agricultural waste, industrial waste and animal bone waste. The mechanisms of morphology formation, microstructure and wettability properties are analysed. Modification strategies for the surface of low-cost ceramic membrane are discussed, and classified into modification for separation application, modification for photocatalytic application and modification for membrane distillation and membrane contactor system. Modification improves the membrane structure by changing the pore size, porosity and wettability properties of low-cost ceramic membranes. Mechanical properties of low-cost ceramic membranes are also discussed in detail towards several mechanism, like grain growth phenomenon and formation of microcracks which also considered as membrane defects. Grain growth phenomenon can be divided into normal and abnormal grain growth. Meanwhile, formation of microcracks could be occurred in single-phase polycrystalline ceramics that have anisotropic grains or biphasic polycrystalline grains. The application of low-cost ceramic membrane in seawater desalination, oily wastewater treatment, heavy metal adsorption, textile separation and photocatalytic application are reviewed. Finally, some possible opportunities and challenges for further development of low-cost ceramic membrane are pointed out.     

Review: membrane materials for the removal of water from industrial solvents by pervaporation and vapor permeation

Organic solvents are widely used in a variety of industrial sectors. Reclaiming and reusing the solvents may be the most economically and environmentally beneficial option for managing spent solvents. Purifying the solvents to meet reuse specifications can be challenging. For hydrophilic solvents, water must be removed prior to reuse, yet many hydrophilic solvents form hard-to-separate azeotropic mixtures with water. Such mixtures make separation processes energy-intensive and cause economic challenges. The membrane processes pervaporation (PV) and vapor permeation (VP) can be less energy-intensive than distillation-based processes and have proven to be very effective in removing water from azeotropic mixtures. In PV/VP, separation is based on the solution–diffusion interaction between the dense permselective layer of the membrane and the solvent/water mixture. This review provides a state-of-the-science analysis of materials used as the selective layer(s) of PV/VP membranes in removing water from organic solvents. A variety of membrane materials, such as polymeric, inorganic, mixed matrix, and hybrid, have been reported in the literature. A small subset of these is commercially available and highlighted here: poly (vinyl alcohol), polyimides, amorphous perfluoro polymers, NaA zeolites, chabazite zeolites, T-type zeolites, and hybrid silicas. The typical performance characteristics and operating limits of these membranes are discussed. Solvents targeted by the United States Environmental Protection Agency for reclamation are emphasized and ten common solvents are chosen for analysis: acetonitrile, 1-butanol, N,N-dimethyl formamide, ethanol, methanol, methyl isobutyl ketone, methyl tert-butyl ether, tetrahydrofuran, acetone, and 2-propanol. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.     

石墨烯基材料在CO2分离膜领域的研究进展

节能高效的CO₂分离技术的开发具有重要的现实及长远意义,膜法CO₂分离在该领域备受关注,具有优异传质特性的新型分离膜材料对膜分离过程有决定性的影响。近年来,石墨烯及其衍生材料因独特的单原子层厚度、亚纳米级别的孔道结构以及优异的机械、化学和热稳定性,成为气体分离膜领域的研究热点,膜的加工难度、技术成本、大面积制备、工作稳定性等问题是限制其实际应用的关键因素。石墨烯基CO₂分离膜主要有三种形式：纳米孔石墨烯膜、层状结构氧化石墨烯膜、基于石墨烯及其衍生材料的混合基质膜。本文综述了石墨烯基CO₂分离膜领域的突破性研究进展,重点介绍了气体的跨膜传质机理和膜的构性关系,总结了膜性能的优化思路和原理,梳理了石墨烯基CO₂分离膜发展面临的挑战,提出了潜在的研究方向。分析表明,进行系统的理论研究,采用先进的表征手段,以建立膜构性关系的理论模型,指导膜结构设计是未来研究的重点。此外,进一步降低膜加工成本,充分研究膜在实际工作环境中的稳定性也至关重要。     

Fabrications and applications of low cost ceramic membrane from kaolin: A comprehensive review

The application of low cost ceramic membrane from kaolin has attracted much interest due to its excellent mechanical stability, chemical and thermal resistivity and most importantly, because it is cost effective, in some cases, compared to polymeric membranes. The advantage of kaolin based ceramic membrane is its thermal properties that allow sintering at much lower temperature than alumina. Although many studies have been made on the application of kaolin based ceramic membranes, detailed discussions were scarcely made and the information on the fabrication of ceramic membrane from kaolin is very limited. This article is aimed to make a comprehensive review on ceramic membrane from kaolin for its fabrication methods and applications. An attempt is also made to show the future direction of the R and D on the kaolin based ceramic membrane.     

State-of-the-art developments in fabricating ceramic membranes with low energy consumption

Ceramic membranes are especially beneficial for treating industrial wastewater due to their satisfactory bending strength, high chemical resistance, and excellent thermal stability. However, the high fabrication cost has restricted their wide applications. Usually, sintering-energy consumption accounts for most of the costs of ceramic membranes, thus increasing the fabrication costs and limiting their application prospects. In this review, we discuss strategies to decrease energy consumption and give meaningful prospects for future work. Easily sintered materials, low sintering temperature, cold sintering process, no sintering process, rapid sintering process, and decrease sintering methods (i.e., co-sintering process and optimized membrane structure) are the main methods treated in this work. This review will provide an important reference for ceramic membranes regarding low energy consumption in the ceramic field.     

Zirconia and titania composite membranes for liquid phase separation: preparation and characterization

Crack-free tubular TiO₂/ZrO₂ composite ceramic membranes on ZrO₂ supports have been successfully synthesized from colloidal titania sols by the sol-gel technique. The pore sizes of the prepared membrane were mainly controlled by the sol properties and the calcination conditions. The influence of different parameters such as additives and solvents on the hydrolysis and polycondensation properties of the sols was studied by DTA–TG and viscosity measurements. The TiO₂/ZrO₂ composite ceramic membranes were characterized by X-ray diffraction and scanning electron microscopy. Composite membrane permeability and rejection properties were also investigated. The results proved that the range of composite membrane flux and retention could be controlled by controlling the amount of polyethylene glycol (PEG). PEG in titania sol systems was suitable for use as an organic additive to fabricate crack-free composite membranes. The larger the amount of PEG added to the precursor solution, the larger the size and number of pores produced in the prepared membranes when the PEG was completely combusted during heat-treatment. By controlling the amount of PEG added to the precursor solution, TiO₂/ZrO₂ composite ceramic membranes with different pore sizes were prepared, which can be used in photocatalytic membrane reactors and applied in liquid–liquid or liquid–solid separation in future research.     

Construction strategies of self-cleaning ceramic composite membranes for water treatment

Ceramic membranes have received much popularity due to their high mechanical strength, satisfactory acid/alkali resistance, and long-term stability. However, ceramic membranes are also inevitably fouled by contaminates during the membrane separation process. Therefore, construction strategies of anti-fouling ceramic membranes are a main topic in current research. In this work, we review a better anti-fouling ceramic membrane, which is named “self-cleaning” membrane and membrane process. Date to now, there are four main strategies to construct self-cleaning ceramic membranes: 1) porous piezoelectric ceramic membranes; 2) photo-catalytic ceramic membrane; 3) electrochemical ceramic membranes and 4) self-cleaning ceramic membrane surface. Self-cleaning ceramic membranes can in-situ remove and decompose the pollutants on the membrane surface and recover the water permeance that exhibits a great potential to treat industrial wastewater without backwashing or other methods. The detailed membrane fabrication period, mechanism and important case studies are reported in this review. Self-cleaning ceramic membrane is expected to be next-generation anti-fouling ceramic membrane material for continuous water treatment. It is a first review work that systematically concluded all the strategies for self-cleaning ceramic membranes that can be an important reference in ceramic or membrane fields.     

Micro‐ and ultrafiltration film membranes from poly(ether ether ketone) (PEEK)

Film membranes from the thermoplastic poly(ether ether ketone) (PEEK) have been extruded and tested for their microfiltration and ultrafiltration performance. High‐performance asymmetric membranes have been obtained by extruding polymer blends of PEEK, polysulphone, and a small molecule solvent mixture, and then by removing the polysulphone and solvent in a subsequent extraction step. The process for making ultrafiltration membranes differs from microfiltration membranes only in the relative blend components, and the temperature of the film pick‐up rolls. Processing parameters with important effects on the membrane performance have been identified. Microfiltration membranes are characterized by their pore‐size distributions and SEM, and ultrafiltration membranes by their rejection of bovine serum albumin, bubble point, and SEM. Composite membrane for nanofiltration utilizing the PEEK ultrafiltration membrane as a substrate performed similarly to a commercial membrane for the same purpose. This work details the best method for making PEEK film membranes published to date. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1146–1155, 1999     

超滤膜技术概述

当今社会,超滤作为一种新型膜分离技术,应用的领域十分广泛,而且也获得了良好的效果。本文首先介绍了超滤技术的原理、四大有机高分子膜材料和相转化制膜中常用的浸没沉淀法和溶剂蒸发法,然后简述了超滤膜的优点、四大领域的应用、三大污染物质及防治措施,并把超滤膜技术多年后的研究方向和未来前景总结出来。指出超滤膜具有在水处理净化、食品提纯和中药分离等方面的诸多优势,接下来在广泛总结颗粒物、有机物和微生物污染的基础上,通过针对性的污染类别,遴选出高效的处理措施,并且能够显著提升超滤膜的抗菌抗污染性能,从而为超滤膜发展和实践运用提供可能。文中提出：今后研究的重点将是制备高性能、低成本、绿色化的超滤膜,并与其他膜分离技术协同作用于生产生活。