Abstract
Magnesium loaded activated carbon was prepared to increase the adsorption capacity of lead (II) ions from aqueous solution. In case of sufficient amounts of surface acidic functional groups existing on the carbon, no significant improvement of heavy metal removal was observed even if the magnesium was loaded on it, but removing surface oxygen compounds by out-gassing in helium flow at 1173 K before magnesium loading, considerable enhancement of the heavy metal adsorption affinity onto the activated carbon could be observed. The amount of magnesium impregnation in the aqueous solution was also increased using the out-gassed carbon in the preparation. Any detrimental effect was not observed for aromatics adsorption by the introduction of magnesium. All adsorption equilibrium results at 293 K obeyed Langmuir isotherms. Heavy metal ions adsorption onto the magnesium loaded activated carbons progressed via ion exchange mechanism. Based on the Boehm titration surface analysis, the strong heavy metal adsorption sites might be generated forming the magnesium bound to carbon surface via oxygen bridge by means of calcining the magnesium nitrate impregnated out-gassing carbon in air at 653 K.
