A review on adsorbents used for defluoridation of drinking water

Drinking water has been contaminated over decades with some very detrimental compounds such as fluoride. Exposure to fluoride through drinking water above the permissible limit (1.0-1.5 mg/L) causes severe dental and skeletal fluorosis. Adsorption technique which deals with adsorbents for fluoride removal from an aqueous solution is a highly efficient and selective process. This review paper provides insights on adsorbents used and developed by researchers for defluoridation of drinking water. It includes various categories of adsorbents used and parameters affecting the whole process. Adsorbents studied by researchers are enlisted with their adsorption capacity, optimum pH, temperature, equilibrium isotherm, kinetics, interfering ions, thermodynamic studies and regeneration procedure adapted. Efforts are needed to develop low cost reusable adsorbents with high adsorption capacity. Although, some adsorbents are reported to show remarkable capacity for fluoride removal; still there is an urgent need for development of more novel adsorbents holding both economic and technological benefits.