Mechanism of simultaneous removal of aluminum and fluoride from aqueous solution by La/Mg/Si-activated carbon.

Mechanism of simultaneous removal of aluminum and fluoride from aqueous solution by La/Mg/Si-activated carbon.
Chemosphere. 2020 Aug;253:126580
Authors: Kim M, Choong CE, Hyun S, Park CM, Lee G
Abstract
La/Mg/Si-activated carbon derived from palm shell has been a suitable material for removal of aluminum and fluoride from aqueous solution. In the study, the mechanism of simultaneous removal of aluminum and fluoride by La/Mg/Si-activated carbon (La/Mg/Si-AC) was investigated to understand its high efficiency. It was found that the removal of aluminum and fluoride by La/Mg/Si-AC was favored at lower pH compared to the point of zero charge of La/Mg/Si-AC and high temperature. Adsorption capacity of Al(OH)4- was about 10 times higher than that of F- due to the strong binding affinity of Al(OH)4- on protonated surface and competition between F- and OH- toward charged adsorption site. Kinetics results showed that the aluminum and fluoride adsorption were explained using the pseudo-second-order kinetic model and intra-particle diffusion model. Adsorption process of Al(OH)4- and F- was driven by the potential rate-limiting step involved in mass transport process occurred on the boundary diffusion layer of porous adsorbent surface. Electrostatic interaction between protonated surface of La/Mg/Si-AC and negatively charged ions (i.e., Al(OH)4- and F-) as well as ion-exchange between hydroxide and ionic metal species were important mechanisms in...

Source: Chemosphere - May 30, 2020 Category: Chemistry Authors: Kim M, Choong CE, Hyun S, Park CM, Lee G Tags: Chemosphere Source Type: research