Enhanced fluoride sorption using La(III) incorporated carboxylated chitosan beads

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

“…8 showed the effect of various co-existing ions of different concentrations on fluoride adsorption by Al-HAP. Except CO 3 2− and PO 4 3− , Cl − , NO 3 − and SO 4 2− have shown negligible effect on fluoride adsorption. Interference was observed on fluoride adsorption by CO 3 2− and PO adsorption capacity was reduced by 10% for an initial CO 3 2− and PO 4 3− concentration of 5 mM.…”

“…Except CO 3 2− and PO 4 3− , Cl − , NO 3 − and SO 4 2− have shown negligible effect on fluoride adsorption. Interference was observed on fluoride adsorption by CO 3 2− and PO adsorption capacity was reduced by 10% for an initial CO 3 2− and PO 4 3− concentration of 5 mM. The reduction in fluoride removal observed by the presence of CO 3 2− and PO 4 3− may be due to competition from these ions for active site [1,3,7].…”

“…Ca(NO 3 ) 2 and Al(NO 3 ) 3 were dissolved in 1 L deionizeddistilled water free from CO 2 at atomic ratios Al/Ca from 0 to 0.5. The total amount of Ca and Al in solution was held at 0.1 mol.…”

“…Excess ingestion of fluoride with high concentration can induce mottling of teeth, softening of bones, even neurological damages [2]. So, fluorosis is an important public health problem all over the world, and an appropriate concentration of fluoride (0.5-1.5 mg/L) is required to prevent dental cavities [3][4][5].…”

“…Among these methods, membrane and ion exchange processes are not very common due to its high installation and maintenance cost, while chemical precipitation results in relatively higher residual fluoride concentration in the effluents [5,7]. Adsorption process is a widely accepted technique because of its ease of operation and cost-effectiveness [3]. Activated alumina is one of the most economical adsorbent for fluoride removal from drinking water.…”