Application of Nanosized Mesoporous Aluminosilicates for Adsorption of Hg+2 from Aqueous Solutions: Kinetic, Isotherm and Thermodynamic Studies.

Mesoporous aluminosilicates, have been prepared with various mole ratios of Si/Al and Cethyltrimethylammonium bromide (CTAB). They have been characterized by infrared, small angle XRD and scanning electron microscopy. The results show that incorporation of aluminum ions in the framework of the mesoporous MCM-41 has turned it into an effective cation exchanger. The uptake% values of mercury ions have been increased. The prepared adsorbents were applied for the removal of Hg(II) from aqueous solution under different experimental conditions by changing contact time, initial concentration of Hg(II), pH, presence of interfering ions and solution temperature. Optimum conditions obtained were pH=5 and contact time of 30 min. The experimental data ?tted very well with the Pseudo-second-order kinetic model. The calculated thermodynamic parameters (?H, ?S and ?G) detected that the adsorption of Hg+2 onto MCM-41, Al10MCM-41 and Al20MCM-41 is an endothermic and spontaneous process. For experimental data the Langmuir isotherm showed a better ?t and maximum adsorption capacity was obtained 100.5, 73.64, 33.92 mg g?1 for Al10MCM-41, Al20MCM-41 and MCM-41 respectively for an initial concentration range 5–200 mg L-1.