Membrane separation method

All the processes are now under the investigation. The processes attracting a great attention as practical methods are 1. Membrane separation method and 2. Low-temperature absorption process. 

Combination of sorption, condensation, and membrane separation methods is used. Various sequences of these methods in the flowchart can be used according to the specific objective. 

This section aims to explain the unique features of membrane separation methods, their superior performance in contaminant removal, and their operational sensitivities and limitations. We focus particularly on the factors that need to be carefully assessed when the membrane technology to be used in the treatment of liquid radioactive waste is being considered. These include membrane configuration and arrangement, process application, operational experience, data related to key performance parameters, and plant and organizational impacts. 

Gas separation membrane technologies are extensively used in industry. Typical applications include carbon dioxide separation from various gas streams, production of oxygen enriched air, hydrogen recovery from a variety of refinery and petrochemical streams, olefin separation such as ethylene-ethane or propylene-propane mixtures. However, membrane separation methods often do not allow reaching needed levels of performance and selectivity. Polymeric membrane materials with relatively high selectivities used so far show generally low permeabilities, which is referred to as trade-off or upper bound relationship for specific gas pairs [1]. 

G. Armas, L. Ferrer, M. Miro, J.M. Estela, V. Cerda, In-line membrane separation method for sulfide monitoring in wastewaters exploiting multisyringe flow injection analysis, Anal. Chim. Acta 524 (2004) 89. 

Dialysis compared with other Membrane-separation Methods... 

In all these membrane-separation methods the distinguishing feature responsible for effecting the desired separation is a membrane which has selective permeability. 

Amongst the membrane-separation methods dialysis is old enough and standardized equipment for this process has long been available. The concentration gradient existing across the membrane is the internally available driving force in the system which is responsible for the phenomenon of dialysis. 

The most recent membrane-separation methods competitive with dialysis are essentially ultrafiltration for separation and concentration of solutes, reverse osmosis for solvent purification and electrodialysis for the separation of charged species from solvents and other solutes or from each other according to charge and mobility. Standardization of membranes and equipment for these newer methods also has more or less been accomplished during the past several decades. In all these methods it is an external driving force or source of energy which is essentially responsible for effecting the desired separation. 

B3. The body uses several membrane separation methods. List as many of these as you can and describe how you think they work. 

This chapter presents an introduction to the four membrane separation methods most commonly used in industry gas permeation, RO, UF, and pervaporation. At the level of this introduction the mathematical sophistication needed to understand the membrane processes is approximately the same as that needed for the equilibrium-staged processes. A background in mass transfer (Chapter 15) will be helpful but is not essential. Detailed descriptions of these membrane separation processes are found in Baker et al. (1990), Eykanp (199Z), Geankoplis (2Q03), Kucera (2010). Noble and Stern (1985), Mohr et al. (1988), Mulder (1996), Osada and Nakagawa (1992), Hagg (1998), Ho and Sirkar (1992). and Wankat (1990). 

Ultrafiltration (UF) is another membrane separation method used to purify liquids. UF is commonly used for recovery of proteins and in food and pharmaceutical applications. It is useful for separating permanent emulsions since the oil droplets will not pass through the membrane. UF is used for the removal of fine colloidal particles, and for recovery of dyes from wastewater. In many applications such as whey processing UF and RO are used in series. The valuable proteins are recovered by UF, and permeate from the UF system is sent to the RO system. The remaining sugars and salts are concentrated in the RO system by removing water. The concentrated permeate can then be fermented to produce ethanol, lactic acid or other products. 

The other technique of artificial immobihzation is the membrane separation method. The major principle of this procedure is to separate the microorganisms from the bulk fluid by the use of sheets of membrane. The membranes will allow the substrates to penetrate to the microorganism s zone, while hindering the microorganisms from mixing with the fluid to be treated (lorio and Calabro, 1995 Sutton and Mishra, 1996). 

A macrocychc ligand containing several carboxylate functional groups (Kobuke et al, 1988) was used in a membrane separation method where the feed contained uranyl acetate (3.3 x 10 M) at a pH value of 4-5, while the receiver phase contained l.OM NaHC03 and U was found... 

The presence of Np in nuclear wastes has been discussed in the context of the chemical aspects and problems associated with the potential use of membrane separation methods (42),... 

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