The regeneration of the pre used ashes in the elimination fluorides ions from the underground waters

After studying the mechanisms and optimization of the conditions of adsorption of soluble fluoride in groundwater (youssoufia-morocco) on fly ash [1],interest has been focused on the regeneration performance of these pre-used ashes to estimate their lifetime. the results showed,firstly,that the desorption is possible and effective step proceeds using a basic solution of ammonia and lime. the optimum desorption conditions are a breakthrough time of at least 30 minutes and a concentration around 1m for lime and 4m for ammonia,with a desorption percentage of 92% .in the second time we have shown that the number of successive adsorption cycles tolerated by the ash is at least 10 cycles. finally,some parameters influencing the desorption such as the concentration of lime,volume to implement,the desorption kinetics were optimized.