Sorption of Fluoride Ions by Hydroxyapatite in a Column System

摘要

The sorption behavior of fluoride ions by hydroxyapatite in a column system from both fluoride aqueous solutions and drinking water from Ojocaliente, Zacatecas, Mexico, was evaluated. The time between two consecutive elutions allowed the rearrangement of the active sites and diffusion of fluoride ions in the hydroxyapatite, resulting in an increase of its sorption capacity. This behavior was not observed with drinking water, probably due to its high bicarbonate ion concentration. The maximum value of C_e/C-o reached for both drinking water and fluoride solutions was 0.73±0.05. The data were fitted to the model of Thomas. Both values of K-(Th) and q0 increased with the number of elutions, and their maximum values were 1.72 ×10~(-3)L mu~(-1)mg~(-1) and 9.91 mgg~(-1), respectively.