Electromembrane processes

T.A. Davis, V. Grebenyuk, O. Grebenyuk in Electromembrane Processes in Membrane Technology in the Chemical Industry (Eds. S.P. Nunes, K.-V. Peinemann), Wiley-VCH, Weinheim, 2001. 

Nagarale RK, Gohil GS, Shahi VK (2006) Recent developments on ion-exchange membranes and electromembrane processes. Adv Colloid Interface Sci 119 97-130... 

Ahlgren, R.M. 1972. Electromembrane processing of cheese whey. In Industrial Processing with Membranes (R.E. Lacey and S. Loeb, eds), pp. 57-69. Wiley-Interscience, John Wiley Sons, New York. 

Nasr-Allah, A. and Audinos, R. 1994. A novel electromembrane process for recovery of tartaric acid and of an alkaline solution from waste tartrates. In Actes du Colloque of the Congres International sur le Traitement des Effluents Vinicoles , pp. 199-202. Narbonne and Epemay (F), June 20-24, 1994. 

Electromembrane processes such as electrolysis and electrodialysis have experienced a steady growth since they made their first appearance in industrial-scale applications about 50 years ago [1-3], Currently desalination of brackish water and chlorine-alkaline electrolysis are still the dominant applications of these processes. But a number of new applications in the chemical and biochemical industry, in the production of high-quality industrial process water and in the treatment of industrial effluents, have been identified more recently [4]. The development of processes such as continuous electrodeionization and the use of bipolar membranes have further extended the range of application of electromembrane processes far beyond their traditional use in water desalination and chlorine-alkaline production. 

The term electromembrane process is used to describe an entire family of processes that can be quite different in their basic concept and their application. However, they are all based on the same principle, which is the coupling of mass transport with an electrical current through an ion permselective membrane. Electromembrane processes can conveniently be divided into three types (1) Electromembrane separation processes that are used to remove ionic components such as salts or acids and bases from electrolyte solutions due to an externally applied electrical potential gradient. (2) Electromembrane synthesis processes that are used to produce certain compounds such as NaOH, and Cl2 from NaCL due to an externally applied electrical potential and an electrochemical electrode reaction. (3) Eletectromembrane energy conversion processes that are to convert chemical into electrical energy, as in the H2/02 fuel cell. 

In electromembrane processes the anions move towards the anode where they are oxidized by releasing electrons to the electrode in an electrochemical reaction. Likewise, the positively charged cations move towards the cathode where they are reduced by receiving electrons from the electrode in an electrochemical reaction. Thus, the transport of ions in an electrolyte solution and ion-exchange membrane between electrodes results in a transport of electrical charges, that is, an electrical current which can be described by the same mathematical relation as the transport of electrons in a metallic conductor, that is, by Ohm s law that is given by ... 

The driving force for the flux of a component in electromembrane processes is a gradient in their electrochemical potential which is given at constant temperature by ... 

The mass transport in electromembrane processes at constant pressure and temperature can be described as a function of the driving force by a phenomenological equation [17], that is, ... 

Unlike electrodialysis, which tends to concentrate and remove or recover species, electromembrane processes transform species present in waste streams by electrolysis and the use of cation and anion exchange membranes. These processes offer chemical cost reduction (by recovery), water consumption reduction, and discharge or reuse of contaminant-free waters. Supplementary gains are also obtained by identifying a market for products obtained from the recovery and transformation processes. 

FIGURE 40.6 Schematic of the ceramic-based electromembrane process for the oxidation of phenol. 

Electromembrane Process for Recovery of Lead Contaminated Soils Phase / Final Report, National Science Foundation, Grant No. ISI-8560730, prepared by PEI Associates, 1986. 

M. Paleologou, R.M. Berry, R. Thompson, and J.T. Wearing, Electromembrane process for the treatment of Kraft mill electrostatic precipitator catch, US Pat. 5,567, 293 H.-J. Rapp and P.H. Pfromm, Electrodialysis for chloride removal from the chemical recovery cycle of a Kraft pulp mill, J. Membr. Sci., 1998, 146, 247-261 P.H. Pfromm, S.-P. Tsai and M.P. Henry, Electrodialysis for bleach effluent recycling in Kraft pulp reduction Simultaneous control of chloride and other no-process elements, Can. J. Chem. Eng., 1999, 77, 1231-1238. 

D. Raucq, G. Pourcelly and C. Gavach, Production of sulfuric acid and caustic soda from sodium sulfate by electromembrane processes. Comparison between electroelectrodialysis and electrodialysis on bipolar membrane, Desalination, 1993, 91, 163— 175 S. Mazrou, H. Kerdjoudi, A.T. Cherif and J. Molenat, Sodium hydroxide and hydrochloric acid generation from sodium chloride and rock salt by electroelectrodialysis, J. Appl. Electrochem., 1997, 27, 558 A.T. Cherif, J. Molenat and A. Elmidaoui, Nitric acid and sodium hydroxide generation by electrodialysis using bipolar membranes. J Appl. Electrochem., 1997, 27, 1069-1074. 

Huffmann, E.L., R.E. Lacey. 1972. Engineering and economic considerations in electromembrane processing. In "Industrial Processing with Membranes". Edts. R.E. Lacey, S. Loeb, pp. 39-55. John Wiley Sons. 

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