Electrochemical degradation Electrical fields

The implications of these electrolysis reactions are enormous in that they impact transport, transformation, and degradation processes that control the contaminant migration, removal, and degradation during electrochemical treatment. The different transport, transfer, and transformation processes induced by the applied electric field and how these processes are impacted by the electrolysis reactions at the electrodes are fundamental to the understanding of the electrochemical remediation technologies and are briefly presented in this section. 

The electrochemical reduction and oxidation of CDs has not yet been fully investigated. A preliminary study by Kessler et al (2004) has shown the potential for various types of CD molecules to degrade in the presence of an electric field. 

In our consideration we have not yet taken into account that liquid crystals are weak electrolytes possessing the corresponding specific properties [2, 3, 97]. Ions could be created by the action of the external electric field, which favors the dissociation of neutral molecules (chemical degradation) or as a result of electrochemical reactions near the electrode boundaries. The latter process is mainly defined by the injection of the additional charge carriers from the electrodes. In some cases, the appearance of electrohydrodynamic instabilities in the nematic phase does not correlate with such crystalline properties as dielectric Ae or conductivity Aa anisotropy. The only physical reason for these instabilities is nonuniform ion distribution along the direction z parallel to the electric field and perpendicular to the cell substrate. 

It should be noted that degradation did not occur on the bare platinum immersed in liquid electrolyte, indicating that this was a specific phenomenon on the catalyst surface-polymer electrolyte interface (Okada et al. 2000). Unlike liquid electrolytes, the polymer electrolyte has immobile cation-exchange sites (sulfonic acid groups on side chains), so when they bind impurity metal cations, the constrained electric double layer lowers the electric field in the electrochemical double layer (Okada et al. 2001). 

The drawbacks of P T has prompted the development of new treatment technologies that are capable of addressing the shortcomings of P T. The application of electrical fields is one of many methods applied to facilitate the removal of contaminants (i). When an electrical field is applied to a clay-rich aquifer, the mobilization and removal of contaminants can be accomplished by electrical heating, electrokinetics, and electrochemical degradation. These processes are described in details in the following sections. 

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