Fluoride Removal from Ground Water by Gama-Alumina Coated Ceramic Honeycomb By K. Dasha , U. S. Hareeshb , R. Johnsonb and J. Arunachalama

Studies have been carried out on defluoridation of ground water using gamma alumina coatings on a ceramic honeycomb. The sol gel coated gamma alumina adsorbent was found to adsorb fluoride rapidly and effectively. Coatings on ceramic honeycomb were prepared using a sol of dispersible precursor of boehmite (-AlOOH). The boehmite coating, on calcination at 500°C transformed to alumina. The fluoride removal performance was investigated as a function of the fluoride concentration and flow rate. It was observed that fluoride removal is low at higher flow rate. The specific fluoride uptake capacity was 15400mg of Fremoved /kg of coated -alumina on the ceramic honeycomb from fluoride solution, whereas in case of ground water, the capacity was 12600 mg of Fper kg of coated alumina. The regeneration was effected by passing a dilute solution of aluminum sulfate solution. A fluoride removal kit consisting of five ceramic honeycombs in series was evaluated to defluoridate ground water. Around 200 liters of ground water (initial Fconc. of 5 ppm) could be defluoridated to permissible level of Fconcentration. It is much easier and convenient to regenerate the alumina coated on the honeycombs due to open channel structures of the honeycomb.