Remediation of Thorium (IV) from Wastewater: Current Status and Way Forward

Abstract

Thorium affects human health and causes environmental issues. The concentration of thorium in the environment may increase due to waste that is produced from human activities like mining, rare-earth extraction, and others. If this waste is not handled properly, thorium may leak and cause water contamination. This review summarises the methods of thorium removal from wastewater. The article addresses the main features of the techniques for thorium removal by physicochemical processes such as chemical precipitation, ion exchange, adsorption, electrochemical and membrane filtration. Their advantages and limitations in the applications are evaluated. Bioadsorption and natural material are widely used in the removal of thorium. However, in the near future, the electrosorption process seems to be the most promising method to treat wastewater since it can overcome limitations of adsorption techniques with the help of electric current to have a more efficient and rapid process. It should be noted that all the techniques able to remove thorium depend on pH, temperature, the concentration of thorium and other wastewater components. In general, the technical applicability, simplicity of technique and cost-effectiveness are the key factors in selecting the most suitable treatment for removal of thorium.