Electrodialysis ED is a separation process commercially used on a large scale for production of drinking water from water bodies and treatment of industrial effluents (Ruiz and et al., 2007). ED system contains ion exchange membranes and ions are transported through ion selective membranes from one solution to another under the influence of electrical potential difference used as a driving force. ED has been widely used in the desalination process and recovery of useful matters from effluents. The performance of ED, depends on the operating conditions and device structures such as ion content of raw water, current density, flow rate, membrane properties, feed concentration, geometry of cell compartments (Chang and et al., 2009, Mohammadi and et al., 2004).The efficiency of ED systems consist in a large part on the properties of the ion exchange membranes. Fouling of ion exchange membranes is one of the common problems in ED processes (Lee and et al., 2009, Ruiz and et al., 2007). Fouling is basically caused by the precipitation of foulants such as organics, colloids and biomass on the membrane surface or inside the membrane and fouling problem reduces the transport of ions. The fouling problemsare occasion to increase membrane resistance, loss in selectivity of the membranes and affect negatively to membrane performance (Lee and et al., 2002, Lindstrand and et al., 2000a,Lindstrand and et al., 2000b). Membrane fouling leads to high energy consumption and poor separation efficiency. Therefore some methods such as pretreatment of the feed solution, turbulence in the compartments, zeta potential control, pH and flow rate optimization, modification of the membrane properties and pulsed voltage have been studied to reduce fouling in ED systems. Also some reducing methods such as chemical methods require additional chemicals, more energy or instruments and those requirements increase the operation and investment cost (Chang and et al., 2009, Lee and et al., 2002, Park and et al., 2003). The fouling problem has been disqualified also by electrodialysis reversal systems EDR. EDR is similar to ED but the direction of ion flow is reversed periodically to break fouling progress by reversing the polarity of the applied electric current. This process is not use only for the removal of fouling but also for removing salts in desalination systems. EDR does not require additional chemicals and it increases membrane life (Bouhidel and Rumeau, 2004, Strathmann, 2010).Fouling of membranes is one of the major problems in ED systems. For this reason there is a need to understand the fouling factors and fouling formation. This study includes brief
Other ID | JA56CV99NV |
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Journal Section | Articles |
Authors | |
Publication Date | July 23, 2016 |
Published in Issue | Year 2016 Volume: 6 Issue: 1 |