Application of Biochar as Filter Media for River Water Purification

Abstract Water bodies around the world are being deteriorated due to the constant release of numerous organic and inorganic pollutants from urbanization and industrialization. Domestic wastewater is often released into the environment untreated in most developing countries, which has a negative impact on the environment overall. The availability of groundwater and surface water is steadily declining, so it is necessary to choose river water as one of the alternate sources. Some significant techniques for water purification are adsorption, biological process, coagulation, chemical precipitation, catalytic processes, membrane filtration, ionizing radiation, magnetically assisted processes, and ion‐exchange. But considering the cost effectiveness, simple gravity filtration technique with different filter medium such as, gravels, sand, charcoal etc. has been studied for river water purification. Adsorption technique is most common and widely used in water purification. Low cost agricultural‐wastes derived Biochar has gained the potential application in adsorption technique of filtration. In this article, different synthesis techniques of biochar, process conditions and limitations of process are properly reviewed. The physical and chemical properties of biochar and factors affecting the properties of biochar have been studied in details. Finally physical activation technique of biochar and its application in water purification has been studied.