At present, the commonly used fluoride removal technologies include adsorption, reverse osmosis, ion exchange, electrodialysis and chemical precipitation. Among them, adsorption is the most common method. The core of adsorption method is the ability of adsorbing materials. The commonly used adsorbing materials include carbon-based apatite, activated alumina, zeolite and bone charcoal.
Activated alumina is one of the most widely used fluoride removal methods abroad, but it has not shown excellent fluoride removal performance in China for various reasons. Activated alumina needs to adjust pH to 5.5 or so in the use process, and has the risk of exceeding the standard of aluminum content in water. If improperly managed, it is easy to cause material hardening and lead to the scrap of the whole equipment.
Zeolite is a kind of fluoride removal material, which has been developed in recent years. Its advantages are low price, stable regeneration, while the shortcomings are low capacity of fluoride removal, huge equipment, high investment and operation cost.
Bone charcoal arose in the 1950s.For the reason of the poor taste of water after being treated and its low strength, it was gradually abandoned.