Fluoride Removal by Electrocoagulation (EC) Process: Aluminum Chemistry and Speciation
When aluminum electrodes are used, the aluminum goes into solution at the anode and produces aqueous
aluminum species and hydrogen gas is released at the cathode. Coagulation with aluminum salts occurs at a wide range of
pH due to different mechanisms. In the EC process, the pH of the coagulation cell increases with liberation of H2 at the
cathode. This increase is mainly dependent on the current for all cases. When pH<4, aluminum remains in the form of Al3+,
and no precipitation occurs, so the fluoride concentration cannot be reduced. When 47, OH- ions
increase in water. In the anodic adsorption layer, the concentration of OH- ions is higher than the concentration of F-, so the
production of the species becomes difficult; therefore, the reduction of fluoride from water and waste water at a range of
pH>7 is affected by the formation of aluminum hydroxide floc. in the abstract. Do not delete the blank line immediately
above the abstract; it sets the footnote at the bottom of this column.
Keywords- Aluminum chemistry, Fluoride removal, Monopolar electrocoagulation process, Speciation.