Fluoride removal by induced crystallization using fluorapatite/calcite seed crystals

The use of electrodialysis with mono-anion permselective membranes for defluoridation

“…Water contamination by fluoride was observed in many regions of the world [3]. It has been estimated that even 200 million people consume water of F -ion content over the permissible level [1,2].…”

“…It migrates to the environment from two sourcesnatural and anthropogenic. Some amount of fluoride migrates to water by dissolving rocks and soils which contain fluoride (like biotite, fluorite, topaz, cryolite, villiaumite) [1][2][3]. In wastewater from phosphoric acid production, the F -concentration can reach even 3000 mg F -/dm 3 .…”

“…Some amount of fluoride migrates to water by dissolving rocks and soils which contain fluoride (like biotite, fluorite, topaz, cryolite, villiaumite) [1][2][3]. In wastewater from phosphoric acid production, the F -concentration can reach even 3000 mg F -/dm 3 . Fluoride also migrates to the environment from ceramic production, food industry, fertilizer manufacturing or electroplating [4,5].…”

“…in India, China, Pakistan, Morocco. In Tanzania the F -ion content in groundwater reached even 330 mg F -/dm 3 . In Kenya the fluoride content of 180 mg F -/dm 3 has been noticed [4,9,10].…”

“…In Tanzania the F -ion content in groundwater reached even 330 mg F -/dm 3 . In Kenya the fluoride content of 180 mg F -/dm 3 has been noticed [4,9,10]. In Tanzania fluoride contamination is so significant that it was necessary to increase the permissible level of F -ions in drinking water to 4 mg F -/dm 3 .…”