Kailash Khulbe

University of Ottawa · Department of Chemical and Biological Engineering

Membrane characterization is an important part of membrane research, development, and engineering. It provides a crucial link between the preparation and performance of the membranes and their structure, chemistry, morphology, transport properties, and other characteristics, with the ultimate goal of understanding how to make the best membrane and...

This chapter describes the materials used for the preparation of synthetic membranes, including also their preparation methods. Synthetic membranes are either ceramic or polymeric. The membranes can be prepared in various shapes such as flat sheet, tubular, hollow fiber, and spiral wound, each with its own special features. Many novel functional na...

Nanotechnology in membrane process has emerged as a boon in various realms and sectors including industry, food, healthcare, electronics, water purification, military, clothing, space and construction etc. There is a significant need for novel advanced water technologies, in particular to ensure a high quality of drinking water, eliminate micropoll...

Gas separation via membrane has been recognized as the main technology that is used for hydrogen recovery, air separation, natural gas sweetening, helium recovery, natural gas dehydration, and so on. The successful application of a membrane-based separation process depends significantly on the appropriate chemical, physical, mechanical, and permeat...

Nanotechnology has been established in membrane technology for decades. In this book, comprehensive coverage is given to nanotechnology applications in synthetic membrane processes, which are used in different fields such as water treatment, separation of gases, the food industry, military use, drug delivery, air filtration, and green chemistry. Na...

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The technique to fabricate nanofibrous mat by electro-spinning has been known for a long time. However, the attempts to use the electospun nanofiber mats, also known as electrospun nanofiber membranes (ENMs), for filtration purposes began only recently. Among many membrane filtration processes, air cleaning by the removal of dust particles has alre...

Thin film composite (TFC) polymeric hollow fiber (HF) membranes are widely used in industrial gas/vapor separations and water treatment. There are many advantages of TFC HF membranes, such as low energy requirements, simplicity of operation, and high specificity. In the present article, a review is made on the progress that has been achieved during...

Nowadays asymmetric thin film composite (TFC) polymeric hollow fiber (HF) membranes are extensively used in industrial gas/vapor separations, water treatment etc. There are numerous advantages to use hollow fibers such as: low energy requirements, simplicity of operation, and high specificity. In the present article we discuss the progress made dur...

Application of polymeric membranes for the adsorption of hazardous pollutants may lead to the development of next-generation reusable and portable water purification appliances. Membranes for membrane adsorption (MA) have the dual function of membrane filtration and adsorption to be very effective to remove trace amounts of pollutants such as catio...

This chapter consists of the following three parts.1.The principle of electroparamagnetic resonance (EPR)2.Review on the application of EPR for membrane characterization3.Future potential of EPR application for membrane characterizationIn part 1, the fundamentals of the EPR spectroscopy is briefly outlined. Part 2 summarizes the EPR characterizatio...

While writing a book on reverse osmosis, it was realized that there had been remarkable progress in recent years in reverse osmosis science and technology. This is a brief summary in which many aspects of RO are discussed, including membrane material and membrane fabrication, membrane characterization, membrane transport, RO module, RO system desig...

Electro–spinning is known as a simple and versatile method to produce nonwoven membranes made out of nanofibers. A wide range of polymers and blends can be used to yield nanofibers. Commonly used membrane polymers such as cellulose acetate (CA), polysulfone (PSU) and polyvinylidene fluoride (PVDF) have been successfully electro–spun to form nonwove...

In this article an attempt is made to review critically the papers published recently on polymeric hollow fibers and hollow fiber membranes. Hollow fiber membranes emerged in early nineteen sixties at almost the same time as the announcement of the cellulose acetate reverse osmosis membrane for seawater desalination by Loeb and Sourirajan. Since th...

Membrane characterisation provides a crucial link between the preparation and performance of membranes and their structure, chemistry, morphology, transport properties and other characteristics. This feature article – published in two parts – covers various characterisation techniques. The first instalment, which was published in the July 2017 issu...

Biobased polymers are materials that are produced from renewable resources. The development of biobased materials is nowadays one of the main world challenges due to their potential to produce fewer greenhouse gases, require less energy, and produce fewer toxic pollutants over their lifecycle than products made from fossil fuels. Mixed-matrix membr...

Membrane characterisation provides a crucial link between the preparation and performance of membranes and their structure, chemistry, morphology, transport properties and other characteristics. This feature article – published in two parts – covers various characterisation techniques. The first instalment, which appears here, looks at why it is ne...

Reverse osmosis (RO) is a water purifcation technology that uses a semipermeable membrane to remove ions, molecules, and larger particles for the production of drinking water. The frst RO membrane for seawater desalination, wastewater treatment and other applications were made of cellulose acetate. But, the polyamide thin-flm composite membrane tha...

Membrane technology has gained acceptance for gas separation and recovery as membranes are friendly to the environment and less expensive. Membranes are starting to play a great role in industries such as separation and production of gases, sweetening of natural gas, processing of biogas and syngas, and oil refineries. This article evaluates the re...

Hollow-fibre membranes are of great commercial interest, with many applications. This article reviews recent progress made – mostly during the last eight years – in polymeric materials for hollow-fibre spinning, the spinning method and the effects of spinning conditions. It was found that amongst the large number of available polymers only a limite...

Understanding the effects of water vapour on gas permeation and separation properties of zeolite membranes especially at lower temperatures is important for the applications of these zeolite membranes for gas separations involving water vapour. Zeolite membranes have high potential for the purification of natural gas, biogas and syn-gas to produce...

Polymers are one of the most fascinating materials of the present era finding their applications in almost every aspects of life. Polymers are either directly available in nature or are chemically synthesized and used depending upon the targeted applications.Advances in polymer science and the introduction of new polymers have resulted in the signi...

Polymeric membranes are becoming increasingly important in the field of separation processes in the pharmaceutical industry, and artificial organs. Some polymers are obtained from natural sources (natural polymer) and then chemically modified for various applications, while others are chemically synthesized (synthetic polymer). Polymeric membranes...

The control of surface roughness of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS) and cellulose (CE) membranes was attempted by changing the rate of nonsolvent influx in the phase inversion process. PVDF and CE were chosen to represent membranes of high hydrophobicity and hydrophilicity, respectively, while PES and PS wer...

The control of surface roughness of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS) and cellulose (CE) membranes was attempted by changing the rate of nonsolvent influx in the phase inversion process. PVDF and CE were chosen to represent membranes of high hydrophobicity and hydrophilicity, respectively, while PES and PS wer...

The control of surface roughness of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS) and cellulose (CE) membranes was attempted by changing the rate of nonsolvent influx in the phase inversion process. PVDF and CE were chosen to represent membranes of high hydrophobicity and hydrophilicity, respectively, while PES and PS wer...

The control of surface roughness of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS) and cellulose (CE) membranes was attempted by changing the rate of nonsolvent influx in the phase inversion process. PVDF and CE were chosen to represent membranes of high hydrophobicity and hydrophilicity, respectively, while PES and PS wer...

The control of surface roughness of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS) and cellulose (CE) membranes was attempted by changing the rate of nonsolvent influx in the phase inversion process. PVDF and CE were chosen to represent membranes of high hydrophobicity and hydrophilicity, respectively, while PES and PS wer...

This book describes the tremendous progress that has been made in the development of gas separation membranes based both on inorganic and polymeric materials. Materials discussed include polymer inclusion membranes (PIMs), metal organic frameworks (MOFs), carbon based materials, zeolites, as well as other materials, and mixed matrix membranes (MMMs...

A membrane is a layer of material which serves as a selective barrier between two phases and is impermeable to specific particles, molecules, or substances when exposed to the action of a driving force. Some components are allowed passage by the membrane into a permeate stream, whereas others are retained by it and accumulate in the retentate strea...

Gas transport through polymers is an area of growing interest as materials with unique transport properties continue to find uses in new, specialized applications ranging from extended life tennis balls to natural gas systems. Membrane users (manufacturers and membrane scientists) require knowledge of membrane characteristics in order to choose an...

Hundreds of thousands of square meters of membrane are needed to perform the required separation of compounds in industrial plants. There are several efficient and economical ways to create a large surface area in a membrane package for effective compound separation. From an overall cost standpoint, not only the cost of membranes per unit area is c...

Gas permeation is a technique for fractionating gas mixtures by using nonporous polymer membranes having a selective permeability to gas according to a dissolution–diffusion mechanism. The membrane gas separation process is driven by a pressure difference across the membrane. The membrane may be either in the form of a flat sheet or a hollow fiber....

Membrane-based gas separation (GS) systems are today widely accepted and, in some cases, used as unit operations for generation, separation, and purification of gases in gas, chemical, petroleum, and allied industries. There are several fields of application of membrane GS, and several membrane materials and membrane modular solutions are available...

The escalating research in membrane fabrication for gas separation applications signifies that membrane technology is currently growing and becoming the major focus for industrial gas separation processes. Material selection and method of preparation are the most important parts in fabricating a membrane. Different preparation methods result in var...

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Membrane separation using hollow fibers has become one of the emerging technologies which underwent a rapid growth during the past few decades. In this article, recent progresses (last 12 years) on polymeric hollow fiber membranes have been discussed. In particular, the following topics were identified as the recent trends in the hollow fiber resea...

Nano-scale materials can be designed to exhibit novel and significantly improved physical and chemical properties. Polymer nanofibers, an important class of nano-materials, have attracted increasing attention in the last 10 years because of their high surface-to-mass (or volume) ratio and special characteristics attractive for advanced applications...

Pharmaceutical and personal care products (PPCPs) enter the environment mainly through municipal wastewater effluents, agricultural run-off, pharmaceutical and related chemical industry discharges. The present study was conducted to remove PPCPs through nano-filtration (NF) membranes prepared with two different tailor-made polymeric additives. The...

At present water crisis is not an issue of scarcity, but of access. There is a growing recognition of the need for increased access to clean water (drinkable, agricultural, industrial use). An encouraging number of innovative technologies, systems, components, processes are emerging for water-treatment, including new filtration and disinfectant tec...

Hydrophilization by treating the membrane surface with water soluble solvent (acids, alcohols, and mixtures of acids, alcohols, and water) is one of the surface modification techniques. Heating and coating are also used to modify the membrane surface. In chemical treatment, the polymeric membrane surface is modified through covalent bonding. Among...

Removal of volatile organic compound (chloroform) from water was carried out by membrane gas stripping using electro-spun poly(vinylidene fluoride) (PVDF) nanofiber membrane. It was shown that the process was feasible. The overall mass transfer coefficient of chloroform through the nanofiber membrane was found to be 2 × 10− 5 m/s at room tempera...

The intensity of the Cu2+ esr signal increased significantly on the addition of CO or SO2, especially with SO2, at room temperature to the preheated (at 400 °C) and evacuated CuO–alumina catalyst. When the CO or SO2 treated sample was evacuated at room temperature, the shape and intensity of the Cu2+ esr line returned to their original values. The...

X-Ray, infrared, and electron spin resonance (e.s.r.) studies were made on the samples prepared by the thermal decomposition of ammonium metavanadate at various temperatures between 100 and 700 °C. A new intermediate compound has been identified to be formed between 100 and 150 °C. This new compound is stable up to 200 °C, and is a complex ammonium...

The reaction between methylacetylene and hydrogen over unsupported nickel, copper, and their alloys has been investigated in a static constant volume system between 20 and 220 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and nearly independent of temperature. While the order of reaction with respect...

The reaction between methylacetylene and hydrogen over pumice supported and unsupported palladium, platinum, iridium, rhodium, and ruthenium catalysts has been investigated between 12 and 160 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and with respect to methylacetylene was zero to slightly negati...

Surface properties of polymeric membranes are of fundamental importance in many branches of industrial applications (e.g. separation of gases, liquid mixtures, filtration, water treatment, desalination, medicine etc.). Hence, it is natural that much attention has been paid to the membrane surface modification. Review of the patents that have appear...

The poly(ether sulfone) (PES) membranes were prepared by blending of two types of surface modifying macromolecules (SMMs)-charged (cSMM) and fluorinated (fSMM). Also, membranes were fabricated in three different conditions: (1) at room temperature (RT) without air-exposure period (the period between film casting and immersion into coagulation bath)...

Significant progress has been made recently in the fabrication of polymeric nanofibers, their characterization and applications, new polymeric materials, theoretical analysis, and so forth. Hence, in this brief review, we report the progress made in these subjects during the last 5 years. Most of the work concerns nanofibers related to the field of...

The development in the area of surface modification of polymeric synthetic membranes since 2000 is reviewed. Many patents, articles, and reviews have been written on the development in the area of surface modifi-cation of polymeric synthetic membranes subjected to RO, UF, NF, gas separation (GS), and biomedical applications, mainly since 2000, but...

This study aims at further improvement and development of the novel hydro–phobic/–philic composite membranes which are made specifically for membrane distillation (MD). This was attempted by studying the effect of the casting conditions during the membrane preparation process by the phase inversion method. Two variables were chosen to study, which...

DESALINATION AND WATER RESOURCES MEMBRANE PROCESSES Membrane Characterization Page131-173 Khulbe KC, Feng CY and Matsuura T, Industrial Membrane Research Laboratory, Chemical and Biological Engineering Department, University of Ottawa, Ottawa, K1N 6N5, Canada 1. Introduction 2. Pore Size Distribution Measurement 2.1. Bubble Gas Transport Meth...

Electro–spinning is known as a simple and versatile method to produce nonwoven membranes made out of nanofibers. A wide range of polymers and blends can be used to yield nanofibers. Commonly used membrane polymers such as cellulose acetate (CA), polysulfone (PSU) and polyvinylidene fluoride (PVDF) have been successfully electro–spun to form nonwove...

This study aims to compare the effect of host hydrophilic polymer on novel hydrophobic/ hydrophilic composite membrane characteristics and desalination performance by direct contact membrane distillation (DCMD). Two different polymers are used for the host polymer: polyethersulfone (PES) and polyetherimide (PEI). The membranes were prepared by the...

Polyethersulfone hollow fiber membranes were prepared by the dry/wet spinning technique under different gas gaps, namely, air, oxygen, nitrogen, carbon dioxide and argon. All spinning parameters were maintained the same. The effects of the gas type on the morphological properties of the hollow fibers were studied in terms of atomic force microscopy...

Polyvinylidene fluoride nanofiber membrane could be used in membrane distillation (MD) to produce drinking water (NaCl concentration <280 ppm) from a saline water of NaCl concentration 6 wt.% by air-gap membrane distillation. This was the first attempt to use electro-spun nanofiber membrane in MD. This new approach may eventually enable the MD proc...

Important membrane surface properties include the size of nodules and nodule aggregates, the shape of pores, the pore size and pore size distribution, and the surface roughness. In this chapter, the focus will be on nodules and nodular aggregates since AFM seems most suitable for those. Moreover, there is evidence that nodular structure has some re...

A large number of SEM pictures have been taken to show the cross-sectional structure of integrally skinned asymmetric membranes and thin film composite membranes. Figures 6.1 [1] and 6.2 [2] are typical examples of such pictures, showing the top skin layer supported by a porous sublayer comprised of either sponge-like pores (Fig. 6.1) or finger-lik...

When we think of microscopes, we think of optical or electron. The former uses a series of glass lenses for magnification of up to x1000. The latter creates a magnified image by focusing electrons, using magnetic fields of special coils. In the evolution of microscopy, the electron microscope improved the magnified image up to x100 000. But both me...

Tis book concentrates on atomic force microscopy (AFM), a method recently - veloped to study the surfaces of synthetic polymeric membranes. AFM is becoming a very important tool for the characterization of synthetic polymeric membranes. Te development of membranes of improved performance depends on the exact kn- ledge of the morphology of a thin se...

From the reviews: "This latest addition to the Springer Laboratory series provides a good overview of membrane technology and the application of atomic force microscopy (AFM) in membrane characterization. It is easy to read ! . In summary, this book presents a good introduction to the field of membrane science and technology. It will be of interest...

Argon plasma treatment enhanced the attachment of epithelial cells to a collagen-based artificial cornea crosslinked using glutaraldehyde (GA) and glutaraldehyde-polyethylene oxide dialdehyde (GA-PEODA) systems. The epithelialization of untreated and treated surfaces was evaluated by the seeding and growth of human corneal epithelial cells. Charact...

Hollow fibers were spun from a solution of surface-modifying macromolecule blended polyethersulfone in dimethyl acetamide by using dry-wet spinning method at different air gaps and at room temperature. The air gap was varied from 10 to 90 cm. The ultrafiltration performance of hollow fibers was studied by using aqueous solutions of polyethylene gly...

Surface film properties of the homopolymers polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA) and the copolymer poly(methyl methacrylate)-co-poly(butyl methacrylate) (PMMA-co-PBMA) and their blends with PS have been examined by atomic force microscopy (AFM) and contact angle measurements. The total and the Lifshitz...

The morphology of the cross section of polyetherimide hollow fiber membranes prepared at different air gaps were studied by the tapping-mode atomic force microscopy (TM-AFM). Samples were prepared by cutting the hollow fiber with a sharp edge at room temperature or by at liquid nitrogen temperature. No significant differences were observed on the m...

The effects of water vapor on CO2/CH4 separation using commercially available poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and Cardo-type polyimide hollow fiber membranes were investigated. Pure methane and CO2/CH4 mixture permeation experiments were carried out in the absence and presence of water vapor (60% RH). Pure methane permeance decreased i...

The internal and external curved surfaces of polysulfone hollow fiber membranes were characterized by atomic force microscopy (AFM), contact angle measurement (CAM), and scanning electron microscopy (SEM) with the aim of improving the membrane surface properties for blood compatibility. Novel approaches were applied to evaluate a number of properti...

Hydroxyl-terminated polybutadiene (HTPB) was blended into a poly(ether sulfone) (PES) casting solution used to prepare ultra-filtration (UF) membranes via the phase inversion technique. The membranes were then characterized by contact angle (CA) measurements and UF experiments. The CA was increased with the addition of HTPB in the PES membrane and...

Dense cellulose acetate, CA, and poly(2,6‐dimethyl‐1,4‐phenylene oxide), PPO, membranes were prepared with and without blending a spin probe, TEMPO free radical, and their ¹³ C solid‐state cross‐polarization magic angle spinning nuclear magnetic resonance, CPMAS NMR, spectra were taken. It was observed that there was no effect of blending TEMPO on...

Surface modified polyethersulfone (PES) membranes via the addition of different hydrophiLic Surface Modifying Macromole- cules (LSMMs) have been developed by Matsuura, Narbaitz and co-workers. This study compares the performance of the best PES-LSMM membrane with nine commercial ultrafiltration membranes manufactured using five different types of b...

Composite membranes, prepared by coating PPO on top of a 12kDa MWCO ultrafiltration membrane (Osmonics-HO51), showed enhanced gas permeability ratio and separation factor for CO2/CH4 gas system, as well as some decrease in the permeability of CO2 gas, in comparison to the dense homogeneous PPO membrane. Average permeability ratio, CO2/CH4, being re...

Hollow fibers were spun from a polyetherimide (PEI) solution in n-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) by using the dry–wet spinning method at different air-gaps. The ultrafiltration performance of hollow fibers was studied using aqueous solutions of polyethylene glycol of different molecular weights. The pure water permeation flux...

Dense flat-sheet membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) using the casting solvents chloroform and 1,1,2-trichloroethylene. X-ray diffraction, tapping mode atomic force microscopy (TM-AFM), and contact angle studies were used to characterize the membranes. The surface energy and the solubility parameters of the PPO...

Incorporation of zeolite to catalyst base-supports generally endows them with improved catalytic properties; especially those related to selectivity and activity. These effects are due to the stronger than normal acidity of zeolites and their molecular sieve effect. Such properties alter notoriously the way in which metals incorporate into a crysta...

Flat-sheet membranes for membrane distillation (MD) were prepared from solutions of polyvinylidene fluoride (PVDF) in dimethylacetamide by the phase inversion technique. Various amounts of water were added to the solutions as a non-solvent additive. The surface of the membranes were investigated by tapping mode atomic force microscopy (TM-AFM), to...

Hollow fiber membranes for hemodialysis were prepared from polyethersulfone (PES) and poly(vinyl pyrrolidone) (PVP) (PES/PVP=18/3 and 18/6 by weight) solution in N,N-dimethylacetamide by the dry wet spinning method. Hollow fibers were then heated either in hot water (95 °C for 30 min) or in air (150 °C for 5 min). These membranes were characterized...

Dense (homogeneous) membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) by using 1,1,2-trichloroethylene as a solvent at 25, 35, 45, 55 and 65 °C evaporation temperature. The effect of temperature used for evaporation of solvent on the characteristics of the membrane was studied by using electron spin resonance, atomic force...

Water treated cellulose acetate (CA) membrane's surface was studied by atomic force microscopy (AFM). It was observed that when CA membrane (water untouched) was treated with water, the morphology of the surface change was detected by AFM. The roughness parameter of the surface was increased. No significant change was observed on the surface on dry...

Asymmetric blend polyethersulfone-polyimide (PES-PI) hollow fiber membranes prepared at different air gap and used for gas separation are characterized by atomic force microscopy (inside and out side surfaces) and by measuring the contact angle of out side surface. The outer surface was entirely different than the inner surface, as expected. On the...

Polyethersulfone (PES) hollow-fiber membranes were prepared by the dry-wet spinning method and then heated in an oven at different temperatures to investigate the effect of heat-treatment on their ultrafiltration performance. It was found that the hollow-fiber membranes shrank by heat treatment, as evidenced by a decrease in flux and an increase in...

The electron spin resonance technique (ESR) was used to study the structure and transport of asymmetric aromatic polyamide membranes. TEMPO (2,2,6,6-tetramethyl-1-piperridinyloxy free radical) was used as a spin probe that was brought into the membrane either by (a) immersion ofthe membranes in aqueous TEMPO solutions, (b) reverse osmosis (RO) expe...