Coal based carbon materials for adsorption of heavy metal ions from solution

The presence of contaminant heavy metal ions like cadmium, mercury and lead in the environment is the major problem due to their high toxicities. The use of activated carbon for the removal of the toxic metal ionic pollutants present in low concentration in solution is of considerable importance. Mongolian bituminous and subbituminous coals were used as raw material to prepare activated carbons by CO2. The coal derived carbons were oxidized with nitric acid in order to introduce surface oxygen groups. The ultimate elemental analysis, Fourier-transform infrared spectroscopy (FTIR), temperature programmed desorption (TPD), and selective neutralization were used to characterize the surface oxygen functional groups of oxidized carbons and naturally oxidized low rank coals. The effect of oxidation and the surface oxygen functional groups on the adsorption properties of the carbon was studied. The remove of heavy metal ions from solution by oxidized carbon and low rank coal was compared. It is observed that the use of lignite could be considerably effective in removing Hg, Cd and Pb cations from solution.