Fluoride removal performance of a new hybrid sorbent of Zr(IV)–ethylenediamine

Removal of fluoride by aluminum impregnated coconut fiber from synthetic fluoride solution and natural water

“…The value of b is found to be increasing along with increasing temperature while the value of q m shows increasing trend from 313 to 353 K, but is decreased at 373 K. The mean adsorption energy (E) is usually employed to differentiate the process of adsorption between chemical and physical. If the value of E is in between 8 and 16 kJ/mol, the adsorption process is said to be chemical while the value below 8 kJ/mol indicates physical adsorption [52,53]. The values of E as determined using Eq.…”

A dendrimer-like hyper branched chitosan beads toward fluoride adsorption from water

“…Many chitosan based adsorbents have been extensively studied for fluoride removal from aqueous solution such as protonated cum carboxylated chitosan beads [13], chitosan/alumina composites [14], chitosan/hydrotalcite composite [15], chitosan/hydroxyapatite based materials [16], zirconium, cerium and lanthanum loaded chitosan/silica gel composites [17][18][19], Zr(IV) loaded collagen fiber [20], lanthanum incorporated chitosan flakes [21], neodymium-modified chitosan [22], chitosan-mixed oxides beads [23], chitosan assisted ethylene diamine functionalized chitosan blends [24], bentonite/chitosan beads [25], hydroxyapatite/chitosan composite [16], Zr(IV) impregnated dithiocarbamate modified chitosan beads [26] etc., Among the different adsorbents, rare earth element incorporated adsorbents are attracting more and more attention due to their selective affinity toward fluoride ions with high sorption capacity, and easy operation [27]. The main advantages of this rare earth element are non-leaching nature as they have higher valence which inturn will not cause any toxic effect to the treated water.…”

β-Cyclodextrin modified hydrous zirconium oxide: Synthesis, characterization and defluoridation performance from aqueous solution

“…The absorption bands found at ν ~3450 cm -1 and ~1630 cm -1 were for stretching and bending modes of O-H bonds in -OH groups, respectively. The band at ν ~500 cm -1 is assigned to the Zr-O bonds in CY-HZO[42]. The band observed at ν ~1400 cm -1 is for the bending mode of Zr-OH group which flattened considerably after fluoride binding, suggesting the replacement of substantial fraction of -OH groups adhered to zirconium.…”