Electrokinetic Remediation for Environmental Security and Sustainability

2Basic Electrochemistry Tools in Environmental Applications

Chanchal Kumar Mitra¹ and Majeti Narasimha Vara Prasad²

Department of Biochemistry, University of Hyderabad, Hyderabad, Telangana 500046, India

School of Life Sciences, University of Hyderabad, Hyderabad, Telangana 500046, India

2.1 Introduction

In simple terms, electrochemistry deals with chemical changes brought about by the passage of electricity, more specifically electric current through a liquid or a solution. In metals, electricity is carried by electrons, and the electrons are free to move around (electrons in the conduction band). Whereas all matter has electrons, in insulators, the electrons are not free to move. The motion of electrons in solids per se does not cause any chemical changes. In solutions, some solutes (salts, for example) can dissociate to form ions (both positive and negatively charged), and they too can conduct current when subjected to an external electric field. Conventionally, the external electric field is usually applied with a pair of metal rods or plates (electrodes) in physical contact with the solution. Chemical changes take place when electrons from the metal surface interact with ions in the solution. This interaction can lead to oxidation‐reduction reactions and also other secondary chemical processes. Essentially, all electrochemical processes take place at or close to the electrode surface, with the electrode acting as a source or sink for electrons.

In some cases, the reverse ...