(165f) Ion Exchange Energies and Selectivities of Heavy Metal Exchanged Nanoporous Zincosilicates

This presentation will report our findings of the exchange energies and selectivities of nanoporous zincosilicates. We have shown these materials capture mercury and lead from aqueous systems. Zincosilicates have similar framework structures to aluminosilicate zeolites; however they typically have a higher ion density due to the need for two counter cations per zinc in the framework as opposed to the one-to-one ratio of counter cation per aluminum of traditional zeolites. Interestingly, microporous zincosilicates do not have "cages" in their structure, which leads to all the cations being accessible. These features lead to high capture capacities of at least 0.2g/gzeolite for divalent heavy metal ions such as lead and mercury whereas other materials maximum capacity is between 0.12-0.17g/gzeolite. Our results have shown that zincosilicates capture high capacities of heavy metals in less than one hour indicating a highly favorable thermodynamic process. We will report the ionic selectivities between mercury and lead and quantify the ion exchange energy in aqueous systems for a series of zincosilicates, such as VPI-7, VPI-9, and VPI-10.