Applications of Membranes in

The first applications of membranes in catalysis [120] principally involved dehydrogenation reactions, where the function of the membrane was simply hydrogen removal. These studies were... 

The second possible application of membrane in the S-I cycle is to separate SO2 from SO3 and O2 gases during the SO3 — 02 + SO2 decomposition reaction. The biggest challenge is that the membrane will have to operate at temperatures between 800 and 950°C, and no existing commercial membrane has been shown to meet these requirements. Work is nnderway at Oakridge National Laboratory to identify and test snitable porous ceramics that are capable of this application. 

This introductory section outlines several established applications of membranes in the chemical and pharmaceutical industries, reviews the membranes and membrane processes available in this field, and discusses the huge potential of these technologies. In addition, other important topic dealing with conservation of natural resources (zeolite membranes) is also presented in this section. Each chapter has been written by a leading international expert with extensive industrial experience in the field. 

While the above-mentioned examples cannot be considered an exhaustive representation of all the possible uses of membranes in the delivery field, they serve to give an idea of how many and how variegated the applications can be. The aim of this chapter is to first describe the basic principles mhng mass transport through membranes. Then, in the light of the administration route (oral, transdermal, and implantable), some of the most important applications are presented and discussed. Finally, future applications of membranes in the dehvery field are briefly treated. 

Challenges and Emerging Applications of Membranes in the Dairy Industry. 660... 

CHALLENGES AND EMERGING APPLICATIONS OF MEMBRANES IN THE DAIRY INDUSTRY 22.6.1 Challenges... 

This section deals with the application of membranes in the treatment of industrial effluent generated by the chemical industries and waste generated by the nuclear industries. Also, this section focuses on important perspectives on environmental engineering with respect to chemical and nuclear waste processing. Before going into the details of the processes used for this purpose, one should understand the background of these types of waste. 

From the Foreword) comprehensive discussion of membrane applications in the chemical, food, and pharmaceutical industries, in biotechnology, and in the treatment of toxic industrial effluents. The applications of membranes in different areas are described by scientists and engineers who not only are experts in membrane science and technology, but also have extensive experience in the specific field of membrane application... ... 

C. Monk, "Application of Membranes in Waste Water Treatment", Proc. of Filtech Conference, Publ. by The Filtration Society, p. 249, October, 1993. 

Several publications on the processing of membranes based on these materials could be found in the literature [5-28]. The selection of membrane material for a given application could be divided in to two parts Screening of materials based on bulk properties and screening based on thin film properties. In the former case, intrinsic material properties such as stability and conductivity will decide the outcome of the research work. In the latter case, the defect free formability of thin film will be the deciding part. The method of film formation as well as the quality of the support substrates could become important in this respect. In supported membranes, material stability and membrane performance are very much related. The most important issue - the application of membranes in high temperature environments - is therefore the study of the stmcture of the membrane/material and its correlation with the stability/durability. 

PushpinderP. 2011. Commercial applications of membranes in gas separations. In Drioli E. and Barbieri G. (eds.) Membrane Engineering for the Treatment of Gases, pp. 215-244. Cambridge, U.K. The Royal Society of Chemistry. ISBN 978-1-84973-239-0. 

Membrane operations have been extensively used in the food industry because they require less manpower, are more efficient, and have a shorter processing time than traditional separation techniqnes, so operational costs are considerably lower than traditional processes [105], For instance, membrane separation processes to clarify and concentrate liquids are less costly than conventional filtration and vacuum evaporation, justifying their application in this field [106]. The primary applications of membranes in the food industry are in the beverage (wine, beer, fruit juices, etc.) and dairy (whey protein concentration, milk protein standardization, etc.), processing industries in the processing of egg prodncts, to a lesser extent, and in water purification. 

As mentioned above, the electrolysis of NaCl to from CI2 and NaOH is the largest application of membranes in electrolytic cells. There are also other brine electrolyzes of commercial importance. NaBr brine is electrolyzed to form Br2-(Another method of Br2 formation is to treat bromide brines with CI2 derived from electrolysis.) Electrolysis of KCl brines is the preferred process for making KOH. Because K ions are less hydrated than Na ions, the membrane is more effective at blocking the backdiffusion of KOH, which allows production of KOH in concentrations as high as 47%. 

Another very large potential application of membranes in ethylene plants is replacing the C2 and C3 splitters. An example of a possible process design is shown in Fig. 7.15. In this example, a two-step membrane system equipped with propylene-permeable membranes is used to split a 50/50 propylene/propane overhead stream from a depropanizer column into a 90% propylene stream and a 90% propane stream. Both streams could then be sent to distillation units for polishing, but the size of columns required would be much reduced. For this design to be feasible, membranes with an olefin/paraffin selectivity of 5 to 10 are required. Many other designs that combine membranes and distillation columns to achieve good separation are possible [23]. 

In the final chapter, we have pooled the thoughts of the contributors to suggest some of the ways in which membrane modification may contribute to the development and application of membranes in the future. 

As previously mentioned, the first widespread commercial application of membranes in GS was the separation of hydrogen in the ammonia purge stream, by using Permea Prism T systems. Hydrogen recovery is applicable to several processes, divided into three main categories ... 

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