Mg-doped nano ferrihydrite—A new adsorbent for fluoride removal from aqueous solutions

Rapid and efficient removal of fluoride ions from aqueous solution using a polypyrrole coated hydrous tin oxide nanocomposite

“…This might be due to the equilibrium shift of Eq. (11) more towards left due to common ion effect at highly acidic pH values and hence the resulting lesser availability of F À ions (pK a HF = 2.95) [39,40].…”

Biosorption of fluoride on Neem (Azadirachta indica) leaf powder

“…Initially the washings 48 were turbid, but after several washings, the washings became clear 49 and at this point washing was stopped. The washed powder was 50 dried for several hours at room temperature and was preserved as The amount adsorbed per unit mass of the adsorbent (q t ) at 92 time t was calculated using the Q3 following mass-balance relations: The specific surface area of the NLP was determined by 101 Methylene blue adsorption method [14,15] and was found to be 102 32.94 m 2 /g, which was higher than that of a number of plant-based 103 adsorbents such as cotton cellulose (1.081 m 2 /g) [16], coffee 104 residue (2.57 m 2 /g) [17], teak tree bark (17.45 m 2 /g) and coconut 105 husk (20.31 m 2 /g) [18], chitosan (2.76 m 2 /g) [19], but much less 106 than that of most commercial activated carbons (800-1500 m 2 /g) 107 [20]. This result indicated that NLP provide considerable surface 108 area for sorption of pollutants.…”

“…It was found that DH varied from À29.92 to where, 'A' stands for the surface of NLP and A À OH represents a 396 surface hydroxyl group. 397 When the pH was low (<5.0), the interactions may lead to 398 formation of weakly ionized HF [19,50] reducing the effective Table 4 Thermodynamic parameters for sorption of fluoride on NLP.…”

Titanium(IV) hydrate based on chitosan template for defluoridation from aqueous solution

“…The increase in DC as the temperature increases may occur because the higher temperature enhances the binding tendency of the F − ions onto the interface, thus increasing the extent of adsorption [44]. Thermodynamic studies show whether the adsorption process is spontaneous [45].…”