Adsorption of some heavy metal oxi-anions such as chromate, dichromate, arsenate and permanganate anions was performed using uncalcined and cetyltrimethylammonium bromide (CTABr)-modified MCM-41 molecular sieves. Because the CTA+ ion can be entered in...
Adsorption of some heavy metal oxi-anions such as chromate, dichromate, arsenate and permanganate anions was performed using uncalcined and cetyltrimethylammonium bromide (CTABr)-modified MCM-41 molecular sieves. Because the CTA+ ion can be entered into the large pore surface of MCM-41, the effective removal of such anions in the modified MCM-41 can be expected. While the calcined MCM-41 had no affinity for these anions, the surfactant modified and uncalcined MCM-41 molecular sieves exhibited significantly enhanced efficiencies for the removal of the oxianions from aqueous solution. MCM-41 molecular sieves are characterized using XRD, SEM, TEM, and TG. The adsorption of oxyanions on the surface of MCM-41 seems to result from a combination of largely Coulombic and minor entropic and hydrophobic effect.