Gómez-De-Arco, L. .; Alzate-Rodríguez, L.; Colpas-Castillo , F. .; Fernández-Maestre, R. . Cation Xanthated Exchangers from Colombian Sub-Bituminous Coals Effectively Removed Cadmium and Lead from Aqueous Solutions . QUIMICAHOY 2011, 2, 23-25.