Widely used defluoridation technologies currently includes adsorption method, electric dialysis method, anti infiltration method, ion exchange method, chemical precipitation method, etc. In addition, adsorption method is the most commonly used. The core of adsorption method is the strength of the adsorbent which commonly used includes activated alumina and zeolite and bone char.
Activated alumina is the most widely used at home and abroad. But it hadn’t show good performances for various reasons. It needs to adjust the pH to 5.5 in the process of using activated alumina. And it has the risk of alumina excess. If it can’t be properly managed, it is easy to cause compaction which may cause the equipment’s discarded.
Zeolite is a new type of defluoridation media in recent years. It has the advantages of low cost and high stability. But the capacity of defluoridation is low which makes the equipment is large and the investment and operating cost is high.
Bone char is a eliminated technology which rose in the 1950s. The reason of being abandon is that the waters taste poor and the strength is low.