Membranes Reference books

There are a number of excellent membrane-related textbooks and reference books available. However, most of these books treat only certain aspects of membrane science and technology in depth while other features related to membranes are only briefly mentioned or not covered at all. The fundamentals of membrane functions and membrane processes are described in detail in a number of publications in the membrane-related literature. The application of membranes, however, is much less comprehensively covered in such books. A large number of interesting membrane applications in the food and drug industry, electrochemical synthesis or biomedical treatment, and energy conversion are published in journals specific for certain industries, which are beyond the interest of many membrane scientists. Therefore, as mentioned earlier, it is difficult to obtain a reasonably complete overview of the very large and heterogeneous field... 

S. Cleghorn, J. Kolde, W. Liu, Catalyst Coated Composite Membranes, Chapter 49, Fuel Cell Reference Book, to be published, Wiley-VCH, 2002. 

In recent years, experience has shown that a large number of hydrophobic ions could act as ion-exchanger ions in liquid membranes and that almost all water soluble ions not unusually hydrophilic, such as Li, may produce a response in such an ISE. These facts have led to an extraordinary increase in publications in this field, although relatively few of these ISEs have actually been used to solve analytical problems. This field, which is becoming rather confused, will not be discussed in this book and the reader is referred to reviews [103-105]. 

The purpose of this chapter is to give a brief introduction to some basic physical objects and concepts that will be referred to throughout this book. Basic elements of these objects are electrolyte solutions, ion-exchange membranes, bulk ion-exchangers, polyelectrolyte solutions, as well as their interfaces—transition layers at their contact. 

The equations (19) may be considered as refined Nemst-Planck equations. These equations combined with the M.S.T. model are treated by F. Helfferich (55) in a very exhaustive manner in the chapter on ion-exchange resin membranes of his book on ion-exchange resins. Extensive literature references are also given here. 

Fluid from solid-phase extraction of wool was placed on simple screen-printed electrodes (an outer membrane was applied with an airbrush) [45]. The solvent was allowed to evaporate and, after an overnight incubation, the activity of the electrodes was measured quickly with reference to that of unexposed electrodes. It was possible to detect the presence of organo-phosphates which had been used to contaminate samples of untreated sheep wool (Fig. 28.3) (see Procedure 41 in CD accompanying this book). 

This membrane is normally employed in what is called a symmetrical configuration , to form the classical ISE which employs an internal reference solution, as sketched in Figure 30.8. This membrane can also be used directly fixed on a solid contact, per example a metallic wire or a screen-printed substrate, in the coated-wire configuration [77]. The proposed Procedure 45 (see in CD accompanying this book) suggests the use of coated wire sensors, as these are the easiest to construct. 

A comprehensive presentation of all membrane types, modules and geometries is beyond the scope of this chapter, reference available membrane books for details [12,17, 55, 60, 71, 77,90]. The examples in Figure 16.2 are an illustration of a typical membrane module and installation. The most widespread FS membrane system is mounted as a spiral-wound (SW) unit. In the SW example the actual membrane module is shown together with how they are mounted inside a pressure vessel. A typical installation is shown where several pressure vessels are subsequently mounted in a stack. Pressurized HF units are typically operated as a crossflow system. In the example shown the HF modules are mounted vertically and arranged in a skid. Several variations of the theme can be found depending on the type of module and the manufacturer, where Figure 16.2 is not specific to a particular item. 

This multiauthor book highlights the current state and advances in membranes and membrane operations referring to three major roles of the membrane mole-... 

In this section the methods developed in the previous section will be applied to analyze the dynamic behavior of integrated reaction separation processes. Emphasis is placed on reactive distillation and reactive chromatography. Finally, possible applications to other integrated reaction separation processes including membrane reactors and sorption-enhanced reaction processes will be briefly discussed. More details about reactive distillation processes were provided in Ref. [39]. For chromatographic reactors the reader should refer to Chapter 6 of this book, for sorption-enhanced reaction processes to Chapter 7, and for membrane reactors to Chapter 12. 

The terminology describing dmg delivery and targeting is extensive and ever-growing. Systems are diversely referred to as controlled release , sustained release , zero-order , reservoir , monolithic , membrane-controlled , smart , stealth etc. Unfortunately, these terms are not always used consistently and, in some cases, may even be used inaccurately. For clarity and consistency, some common terms used in this book are defined as follows ... 

High temperature membranes, that can operate at temperatures above 100 °C, are desirable to promote heat rejection, speed up electrode reaction rates, and to improve tolerance to impurities. This is an active area of materials research. Unfortunately, space constraints preclude a detailed description of fuel cell technologies and the underlying issues. Instead, the reader is referred to excellent reviews and books that exist on this topic.45 47... 

PEMFC (Proton Exchange Membrane Fuel Cell) and SPFC (Solid Polymer Fuel Cell) are the two competing mnemonics of a low-temperature fuel cell type originated for use in space by General Electric, USA. To reflect present practice, the author will use PEFC (Proton Exchange Fuel Cell). The DMFC (Direct Methanol Fuel Cell) also uses proton exchange membranes, but is referred to by its own mnemonic. Proton exchange between polar water molecules is discussed by Koryta (1991 1993) and in the introduction to this book. 

Throughout the rest of this book we will represent the actual electrical potential difference across a membrane, B — °, by EMy where M refers to membrane. Hence, for both equilibrium and nonequilibrium situations, we have El — E° = AE = Em- When a particular ionic species / is in equilibrium across some membrane, EM equals which is the Nernst potential for that... 

When a homogeneous catalyst, that is an enzyme, is immobilized there are in principle three different approaches [3]. The enzyme can be adsorbed onto a carrier, it can be encapsulated in the carrier, or it can be covalently attached to the carrier. In an extreme case of covalent attachment the enzyme can be cross-linked, making a carrier uimecessary. The choice of immobiUzation method and carrier can greatly influence the properties of the immobiUzed enzyme, ideally improving them. To date many excellent reviews [5-13] and even comprehensive books [14] on the topic of enzyme immobiUzation have been written. Many of these reviews and books use their own division of approaches they range from three to eight and can also include membrane techniques. In order to ease the comparison with chemical catalysts, a division according to reference [3] was chosen. This chapter aims to demonstrate, with examples from the research performed within the COST D25 Action, the importance of the area under discussion. 

We will perform the Leaf disk test, also known as leaf disk assay or leaf disk choice test, the second of two bioassays of tannins in the diet of insects in this book. In this often used bioassay, leaf sections of a standard size are treated with the compound(s) in question. Several circular leaf sections ( leaf disks ) (Ali et al. 1999, Filho and Mazzafera 2000, Shields et al. 2008, Wheeler and Isman 2000) or cellulose membrane filters (Hollister and Mullin 1999, Larocque et al. 1999) are presented to a caterpillar in a choice experiment. We measure how much chow the caterpillar has consumed and whether any feeding inhibition is concentration dependent. Regardless of what compounds are being tested, leaf disk tests serve as an important tool in bioassaying feeding inhibitors and stimulants in insects. The cited references are examples of such studies. (In the first tannic acid experiment - Chap. 18 - the tannic acid was mixed into diet in varying concentrations.)... 

It is not the intent of this book to get into any details of organic polymeric membranes. The readers, therefore, are referred to some recently published books in this field for the synthesis, characteristics and applications of various organic membranes [Belfort 1984 Lloyd, 1985 Sourirajan and Matsuura, 1985 Baker, 1991]. 

The basic principles of transport across a semiper-meable membrane and the relevant thermodynamic and flux equations governing transport are well established. Books on transport appear quite regularly and often include this material in an introductory chapter (8). Friedman (5)/ Fournier (9) and Lakshminarayanaiah (10) give quite exhaustive treatments of the problem from the bioengineerings biophysical, and biological points of view. The following discussion, with reference to Figure 14.1 and Table 14.1, is limited to the most basic thermodynamic equations and a qualitative discussion of the principles. 

All the materials mentioned above are discussed in the current chapter. If possible, SI units are applied for the data— the reader may find a useful table for conversion of units in Ref. [16]. Many good review papers and chapters in books on membranes for gas applications have been published recent years only a few are referred to here [17-19]. A rich source of information on membrane materials and gas separation may also be found on the Web site of membrane producers and research institutes. One example is MTR [20]. 

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