Electrochemical water pollutant removal; can we make it sustainable?

Abstract

Water pollution is a serious environmental problem which creates health, economical, and ecological impacts all over the world. Pollution occurs through many routes such as industrial effluents, usage of agro-chemicals, and domestic wastewater effluents. While minimizing such contaminations can be the ideal control measure, treating contaminated water prior to discharge is more practical in protecting human and environment. Water treatment processes can be biological, physical, chemical or their combinations. While biological treatment methods are cheaper and more sustainable in nature, treating persistent and toxic chemicals may not be easy using them. Combinations of physical and chemical treatment technologies, i.e. physicochemical technologies, are more powerful in dealing with persistent and toxic pollutants. Electrochemical technology can be labelled as a “single step” physicochemical treatment process. In electrochemical technologies, anodic reactions produce a series of oxidants in-situ. Therefore, no chemical storage or handling is required. Besides, direct oxidation of contaminants at the anode also possible. Applied voltage field creates simultaneous physical destruction. In addition, cathodic reduction provides an excellent environment for pollutant removal (e.g. heavy metals). However, above technology need electrical energy to operate. Since energy is one of the most discussed global problems, making electrochemical technologies “sustainable” is important. This paper will discuss possible pathways to reduce the energy requirements in electrochemical technologies, using both experimental findings and literature. Moreover, possibilities of using alternative energy supplies to make the above technology sustainable will be discussed.