Methods of fluoride removal from water

Abstract

In view of growing evidence of natural and anthropic contamination by fluoride ion (F-) in several aquifers used for water supply, this paper analyzes the main types of available traditional and alternative treatments for its removal. The most applied method relies upon adsorption, mainly using activated alumina. However, new materials to replace the alumina have been studied in order to cheapen costs and increase the efficiency of treatment. Alternative materials that have been highlighted lately are the biochars – produced by calcination from many different types of biomass – and natural and synthesized nanoparticles. In addition to adsorption, there are other methods such as chemical and electrochemical treatments, use of membranes, and phytoremediation. However, the choice of the best method will depend upon the characteristics of each technique as well as of the water to be treated. In making a choice, it is necessary to take into account not only the cost and efficiency of the process, but also the waste generated by the treatment – such as the adsorbent material, slurries and liquid effluents concentrated with F- - and its proper disposed.