Removal of Lead by Nanosized Mesoporous Aluminosilicate from aqueous systems

This paper shows how nanoporous MCM-41 was altered by incorporation of Al ions as a speedy, simple and cheap method for modification. The mesoporous aluminosilicates were synthesized with various mole ratios of Si/Al and cetyltrimethylammonium bromide (CTAB). They were characterized by infrared, small angle XRD and scanning electron microscopy. A series of experiments were proceeded to different conditions. The adsorption capacity is extremely high in the pH range 3-6 and decreasing with decreasing pH value. Time of equilibration was monitored for 15 min. Adsorption capacity was enhanced with the increase of aluminum in the framework of the adsorbent. Adsorption behavior of lead ion on MCM-41 and mesoporous aluminosilicate was studied. Langmuir isotherm fits the experimental data very well. A thermodynamic study showed spontaneity of the sorption. Positive values of enthalpy and entropy indicate endothermic and increase in order of randomness at the solid-solution interface throughout sorption. The adsorption of lead ions onto the studied adsorbents follows pseudo-second-order kinetics.