Ultrafiltration industrial application

The concentrate derived from ultrafiltration is usually a thick colourless gel containing about 4-8% solids. This must contain an antimicrobial agent to inhibit microbial growth and biological degradation. The type of antimicrobial agent used depends on the particular application for the exopolysaccharide. For example, the nature of file antimicrobial agent is less critical for industrial applications, such as enhanced oil recovery, than for use in cosmetics. 

A limitation to the more widespread use of membrane separation processes is membrane fouling, as would be expected in the industrial application of such finely porous materials. Fouling results in a continuous decline in membrane penneation rate, an increased rejection of low molecular weight solutes and eventually blocking of flow channels. On start-up of a process, a reduction in membrane permeation rate to 30-10% of the pure water permeation rate after a few minutes of operation is common for ultrafiltration. Such a rapid decrease may be even more extreme for microfiltration. This is often followed by a more gradual... 

Cot, L., C. Guizard and A. Larbot. 1988. Novel ceramic material for liquid separation process Present and prospective applications in microfiltration and ultrafiltration. Industrial Ceramics 8(3) 143-48. 

For the production of chemicals, food additives and pharmaceutical products, homogeneous catalysis offers some attractive features such as a high selectivity and activity, e.g. in asymmetric synthesis. However, since most homogeneous catalysts are relatively expensive, their current industrial application is limited [3]. On the other hand, heterogeneous catalysts can easily be separated from the products and can be recycled efficiently. Membrane separations with emphasis on nanofil-tration and ultrafiltration will allow for a similar recyclability of homogeneous catalysts, which is important both from an environmental as well as a commercial... 

This membrane industry is very fragmented. Industrial applications are divided into six main sub-groups reverse osmosis ultrafiltration microfiltration gas separation pervaporation and electrodialysis. Medical applications are divided into three more artificial kidneys blood oxygenators and controlled release pharmaceuticals. Few companies are involved in more than one sub-group of the industry. Because of these divisions it is difficult to obtain an overview of membrane science and technology this book is an attempt to give such an overview. 

Various membrane operations are available today for a wide spectrum of industrial applications. Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), gas and vapor separation (GS, VS), pervaporation (PV), dialysis (D), electrodialysis (ED) and membrane contactors (MCs) are only some of the best-known membrane unit operations. 

Numerous studies relating to the application of ultrafiltration have been presented in the literature. For example, protein ultrafiltration has been studied by Kozinski (1972). Separations of complex aqueous suspensions and organic solutions have been reported by Bhattacharyya (1974, 1975). Industrial applications have been reviewed by Klinkowski (1978). Theoretical aspects of ultrafiltration have been discussed by Michaels (1968), Porter (1972), Shen (1977) and others. 

The most common uses of RO are for desalination of seawater and brackish water for potable and industrial applications. However, as demand for fresh water grows, RO is being pressed into service for wastewater and reuse applications. These will require extensive pretreatment, sometimes involving other membrane technologies such as micro- or ultrafiltration, to minimize fouling of the RO membranes (see Chapter 16). 

Membrane separation is a relatively new and fast-growing field in supramolecular chemistry. It is not only an important process in biological systems, but becomes a large-scale industrial activity. For industrial applications, many synthetic membranes have been developed. Important conventional membrane technologies are microfiltration, ultrafiltration, electro- and hemodialysis, reverse osmosis, and gas separations. The main advantages are the high separation factors that can be achieved under mild conditions and the low energy requirements. 

Industrial Application of Ultrafiltration and Hyperfiltration in the Food and Dairy Industries... 

An industrial application of dialysis is the recovery of caustic from hemi-cellulose solutions produced in making rayon by the viscose process. Flat-sheet membranes are placed parallel to each other in a filter-press arrangement (see Chap. 30, p. 1004) and water is passed countercurrent to the feed solution to produce a dialyzate with up to 6 percent NaOH. Recovery of salts or sugars from other natural products or other colloidal solutions could be achieved by dialysis, but ultrafiltration is more likely to be used because of the higher permeation rates that can be obtained. 

The use of membranes in cartridge microfihration has be discussed already in Chapter 6, Section 6.6. That section also contained a number of test procedures enq)loyed for membrane characterisation which will not be repeated here. This chapter provides details of membrane configuration other than cartridges, mathematical models to assist in the understanding and control of the processes. Industrial applications or investigations of microfiltration and to a lesser extent ultrafiltration are also discussed. 

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