Removal of Hexavalent Chromium (Cr6+) Using Different Natural Adsorbents - A Review

Abstract

Heavy metal is one of the major environmental and ecological problems in this world. The presence of heavy metals in water and wastewater causes toxic effects to the living beings and the environment. Compared to other heavy metals (such as Cr6+, Pb2+, Zn2+ etc.,) Chromium found in the tannery and electroplating industrial effluents causes serious effects to the humans and living organisms. It also contaminates the soil and groundwater. The excess amount of chromium affects the lungs and lead to respiratory disorders in the human beings. Due to a large number of tanneries and electroplating industries, the chromium contamination in the wastewater and aqueous solutions exceeds the tolerance limits. Many methods are used to remove the chromium from the aqueous solutions and industrial effluents. Adsorption is one of the cost - effective methods being widely used for the removal of heavy metals from industrial and commercial wastewaters. It has been established as an important and economically feasible treatment technology for removing heavy metals, particularly chromium. This review article presents the information about the application of different kinds of natural waste adsorbents for the removal of hexavalent chromium (Cr6+) from industrial effluent.