Heavy metals, such as Cr, As and Hg, can lead to groundwater pollution and undesirable human health effects. Mesoporous silica has a very high surface areas and a readily modifiable surface.  Covalant modification of mesoporous silica is routinely used to optimize the adsorption of heavy metal contaminants through enhanced binding and/or favorable electrostatic interactions. In this study, the adsorptive properties of mesoporous silica and the magnetic properties of iron oxide were combined to prepare a high surface area composite nanomaterial that can adsorb heavy metals and can be recovered using magnetic separation. Magnetic iron oxide nanoparticles were coated with mesoporous silica (MCM-41) to prepare magnetic mesoporous silica (m-MCM-41) with an overall diameter of approximately 100 nm. The resulting materials were functionalized with organosilanes containing amine and thiol functionalities.  The magnetic MCM-41 nanoparticles exhibited the highest adsorption capacity for Cr(III) at pH=5.4 relative to the parent, nonmagnetic MCM-41.  The Cr(III) adsorption capacity was attributed to a synergistic effect between the iron oxide cores and the MCM-41.  Spectroscopic studies are in progress to better understand the molecular details of the adsorption of heavy metals. The magnetic MCM-41 samples showed relatively low arsenic adsorption capacities.

Adsorption of heavy metals on functionalized magnetic mesoporous silica nanoparticles

247th National Meeting (2014)

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