Reverse osmosis/electrodialysis

Hardness Calcium, magnesium, barium and strontium salts expressed as CaCOa Chief source of scale in heat exchange equipment, boilers, pipe lines, etc. forms curds with soap interferes wKh dyeing, etc. Softening, distillation, internal boiler water treatment, surface active agents, reverse osmosis, electrodialysis... 

Suifate (S04>-2 Adds to solids content of water, but, in itself, is not usually significant combines with calcium to form calcium sulfate scale Demineralization, distillation, reverse osmosis, electrodialysis... 

Fiuoride F- Not usually significant industrially Adsorption with magnesium hydroxide, calcium phosphate, or bone black Alum coagulation reverse osmosis electrodialysis... 

Dissolved Solids None Dissolved solids is measure of total amount of dissolved matter, determined by evaporation high concentrations of dissolved solids are objectionable because of process interference and as a cause of foaming in boilers Various softening processes, such as lime softening and cation exchange by hydrogen zeolite, will reduce dissolved, solids demineralization distillation reverse osmosis electrodialysis... 

Steam stripping Air stripping Biological nitrification Chemical oxidation Ion exchange Solvent extraction Biological oxidation (aerobic) Wet oxidation Activated carbon Chemical oxidation Chemical precipitation Ion exchange Adsorption Nano-filtration Reverse osmosis Electrodialysis... 

The most widely used techniques for removing dissolved inorganic solids are boiling, addition of washing soda, lime-soda softening, complexation, sodium ion exchange, demineralization, reverse osmosis, electrodialysis, adsorption onto suspended solids, and aeration. 

Developed industrial membrane separation technologies Microfiltration Ultrafiltration Reverse osmosis Electrodialysis Well-established unit operations. No major breakthroughs seem imminent... 

Reverse osmosis/electrodialysis (RO/ED), in which inorganic solutes are removed using ED and water is removed using RO. Not all inorganic solutes are removed by this method. 

Reverse Osmosis/Electrodialysis. Very recently, Perdue and co-workers have developed a novel process in which reverse osmosis (RO) is used to remove water from seawater and electrodialysis (ED) is used to desalt seawater. The coupled RO/ED process was developed initially by Koprivnjak et al. (2006) to purify RO-concentrated samples of DOM from freshwaters, which are nearly always contaminated with sulfuric acid (H2S04) and silicic acid (H4Si04). It was possible to remove nearly all H2S04 and H4Si04 from such samples with an average 85% overall recovery of DOC. 

Koprivnjak, J.-F., Pfromm, P. FL, Ingall, E., Vetter, T. A., Schmitt-Kopplin, P, Hertkorn, N., Frommberger, M., Knicker, H., and Perdue, E. M. (2009). Chemical and spectroscopic characterization of marine dissolved organic matter isolated using coupled reverse osmosis-electrodialysis. Geochim. Cosmochim. Acta, in press. 

For radioactive effluent treatment, the relevant membrane processes are microfiltration, ulfrafiltration (UF), reverse osmosis, electrodialysis, diffusion, and Donnan dialysis and liquid membrane processes and they can be used either alone or in conjunction with any of the conventional processes. The actual process selected would depend on the physical, physicochemical, and radiochemical nature of the effluents. The basic factors which help in the design of an appropriate system are permeate quality, decontamination, and VRFs, disposal methods available for secondary wastes generated, and the permeate. 

Ion exchange desalination - DESAL , SIROTHERM Membrane desalination - Reverse Osmosis, Electrodialysis Continuing fixed bed counterflow development Condensate polishing systems Ion Chromatography analysis, and Pellicular resins Polymeric adsorbents... 

Synthetic membranes with calibrated pores are used for various operations in the wine industry ultrafiltration, front-end microfiltration, tangential microfiltration and reverse osmosis. Electrodialysis and pervaporation, special separation techniques described elsewhere in this book (Section 12.5.1), also make use of membranes. 

Concentration of Sodium Sulfate Solutions. A concentration unit is always necessary for both two- and three-compartment cells when the feed consists of dilute sodium sulfate solutions, because the cell voltage increases rapidly when the sodium sulfate concentration is <10%. The methods available are reverse osmosis, electrodialysis, and evaporation. With the present average European prices of steam and electric energy, evaporation seems to be the best method for concentrating up to 20% diluted feed solutions having a salt content around 3-5%. 

Drinking water, reduced hardness water, unsalted cheese Reverse osmosis, electrodialysis, NF... 

Electrodialysis (ED) is used to remove ionized substance from hquids through selective ion-permeable membranes. ED is the most widely commercialized electromembrane technology. Desalination of brackish water is the area of electrodialysis application with the largest number of installations. This chemical-free technology competes with reverse osmosis. Electrodialysis shows better resistance to fouling and scaling. It also has an economical advantage in desalination of low-salinity solutions [13]. Also, it should be kept in mind that because of small material consumption ED is the most environmental friendly process for solution desalination [14]. 

It is important to mention that for the analysis of low-halogen anionic concentration, high-purity water, the so-called reagent water [88] is needed to dilute the sample to prepare standard solution and eluent. Different kinds of water purification methods, like distillation, ion exchange, membrane filtration, reverse osmosis, electrodialysis, and their combination, can be successfully used for the production of reagent-grade water. 

Desalination (0011-9164) (1873-4464). Desalination covers all desalting fields—distillation, membranes, reverse osmosis, electrodialysis, ion exchange, freezing, water purification, water reuse, and wastewater treatment—and aims to provide a forum for any innovative concept or practice. 

Ultraflltration is also used to fractionate and concentrate proteins from potato processing wastewaters. Other protein wheys can be processed by reverse osmosis. Electrodialysis is used for a number of applications in the food and beverage industry, including deionization or deacidification of fruit juices, wines and, in the dairy industry, milk and whey. It often competes directly with ion exchange processes. 

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