Removal of fluoride and arsenate from aqueous solution by hydrocalumite via precipitation and anion exchange

Mechanism of boron uptake by hydrocalumite calcined at different temperatures

“…Within the LDH family, however, there are other compositions. For representative example, hydrocalumite (Ca 2 Al(OH) 6 A − ), which is also called AFm in cement science literature [23,24]. Hydrocalumite can be easily developed in neutral and fly ashes when a simple lime treatment was applied and it is a type of LDH with well-ordered Ca and Al located in the hydroxide layers and 6-fold coordinated Al 3+ , as in hydrotalcite.…”

“…Unlike hydrotalcite, the main removal mechanism of anionic contaminants by hydrocalumite is dissolution-precipitation because of its higher solubility than hydrotalcite [23]. In this process, hydrocalumite is dissolved to release Ca 2+ , Al(OH) 4 − , and A − , and then the contaminant is precipitated with Ca 2+ .…”

Effects of hydrofluoric acid pre-deashing of rice husk on physicochemical properties and CO2 adsorption performance of nitrogen-enriched biochar

“…Basically, the HF solution effectively removed Si and K, but not Mg, Ca, or Fe. The likely mechanism behind this is that compounds containing Si react with HF to form SiF 4 , while compounds containing Mg, Ca, and Fe tend to react with HF to form insoluble or just slightly soluble compounds; a similar mechanism exists for P and S. The most likely reaction mechanisms can be expressed as follows [28]: Fig. 2 shows FESEM images of RH, HF-RH and HF-N-Char.…”

Synthesis of iron oxyhydroxide nanoparticles and its application for fluoride removal from water

“…Various colloids have been also investigated to remove the different types of harmful ions from water [1]. Methods of water treatment that can be used other than using those colloids to remove ions from water are membrane separation processes [3], electrochemical precipitation [4], ion exchange [5], and solvent extraction [6]. These methods for removal of hazardous ions from water have different disadvantages such as problem associated with disposal of ionic sludge, high investment and operational cost [6].…”