Electrochemical techniques for a cleaner

Important advances in electrochemical engineering technology over the last three decades have fostered the development of a lternative methods to alleviate and prevent the generation of pollutants which damage the environment. The feasibility of zero emission of pollutants during production pro cesses was envisaged over 30 years ago. In practice, this strategy is difficult to achieve and technologies to minimize and to convert pollutants into environmentally harmless sub-products are a more realistic and feasible option. In this article, the advantages and limitations of advanced electrochemical technologies are considered. Such technologies include waste-water treatment and metal ion recovery together with direct and indirect methods for oxidation of organic compounds. Electrochemical technologies have also contributed to methodologies for the elimination of noxious gases such as carbon dioxide, nitrous oxides and sulfur dioxide. Electrochemical methods are also usef ul in the treatment of metal- and organic contaminated soils. This article also summarizes the generation of clean energy from fuel cells which has achieved worldwide rec ognition as an alternative source of energy for transportation vehicles. Several fuels including hydrogen, methanol and hydrocarbons have been proposed in the open literature but hydrogen/oxygen fuel cells are amongst the most advanced systems at the present time. Electrochemical technologies are also proposed for electricity storage generated in power plants and renewable sources of energy during periods of low demand.