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 (γ-AlOOH). The boehmite coating, on calcination at 500°C transformed to γ-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 F removed /kg of coated γ-alumina on the ceramic honeycomb from de-ionized water, whereas in case of ground water, the capacity was 11080 mg of F per 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 F conc. of 5 ppm) could be defluoridated to permissible level of F concentration. It is much easier and convenient to regenerate the alumina coated on the honeycombs due to open channel structures of the honeycomb.

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