FUNDAMENTALS OF SPECIFICATION FOR SORBENT IN DEFLUORIDATION OF DRINKING WATER

Fluoride is a typical component of natural waters and its concentration varies depending on the water resource. Water may be contaminated by natural sources like more alkaline ions (CO3 2-+HCO3 ->10.4 meq/l water) reacts with halite which comes from industrial effluents. This is ensuing in fluoride concentrations up to 12.7 mg F– /l where ground level of water is low. WHO standards and BIS: 105000, 1991 permit only 0.5-1.5 mg/dl as the upper permissible limit for fluoride in drinking water for the Indian context. Fluoride in excess of the permissible limits in drinking water causes a number of endemic conditions referred to collectively as “fluorosis”. This paper explores the sorptive answer of a recently developed adsorbent, Activated alumina finely grinded with coconut shell powder. The efficiency of the sorption of fluoride ion is affected by pH, contact time, adsorbent dose, type and size of adsorbents. The adsorption equilibrium is well correlated by Freundlich and Langmuir model