Evaluation of phosphate removal from water by calcined-LDH synthesized from the dolomite

摘要

In the present study, the characteristics of the adsorption of phosphate on calcined layered double hydroxides (LDHs) from aqueous solution were evaluated under laboratory conditions. The anionic clays were Mg_3pH _(10)-LDH synthesized by co-precipitation and D_1pH _(10)-LDH synthesized from the dolomite. The equilibrium isotherm showed that the uptake of phosphate ion by Mg_3pH_(10)(500)-LDH was in agreement with the Langmuir and Freundlich equations; the Langmuir model gave a better fit to the experimental data than the Freundlich one. The equilibrium isotherm showed, however, that the adsorption of the phosphate on D _1pH_(10)(500)-LDH was accompanied with precipitation reaction of the phosphate salts. A mechanism proposed for the removal of phosphate ion has been confirmed by X-ray diffraction and FT-IR spectroscopy.