Insights into the ion-exchange properties of Zn(ii)-incorporated MOR zeolites for the capture of multivalent cations.

Understanding the properties of zeolites for cation exchange is important because the ion-exchange performance largely determines their suitability in applications such as catalysis and adsorptive separation. We synthesized a Zn(ii)-incorporated mordenite-framework aluminosilicate zeolite (Zn,Al-MOR), in which both Zn and Al are substituted in the framework, and studied its ion-exchange behavior for multivalent cations. For comparison, the original aluminosilicate mordenite (Al-MOR) was also synthesized with a composition adjusted to ensure that its charge density was similar to that of Zn,Al-MOR.

Increasing the ion-exchange capacity of MFI zeolites by introducing Zn to aluminosilicate frameworks.

MFI zeolites exchanged with various cations have gained a great deal of attention as catalysts. Increase in the ion-exchange capacity of zeolites can improve their catalytic properties by introducing more active sites; however, the ion-exchange capacity of MFI zeolites is limited by maximum aluminum content in the structure. To improve the ion-exchange capability of the MFI zeolites beyond the upper limit of the aluminosilicate MFI zeolites, we propose herein an approach to incorporate Zn(ii) in the zeolitic framework, because Zn in the framework sites generates two negative charges per atom.

Synthesis of New Microporous Zincosilicates with CHA Zeolite Topology as Efficient Platforms for Ion-Exchange of Divalent Cations.

There is growing interest to develop zeolite materials capable of stabilizing divalent cations such as Cu , Fe , and Ni for catalytic applications. Herein the synthesis of a new microporous zincosilicate with CHA zeolite topology is reported for the first time, by particularly focusing on the mixing procedures of the raw materials to prevent the precipitation of zinc oxides/hydroxides and the formation of impurity phases. The obtained zincosilicate CHA products possess remarkably higher ion-exchange ability for catalytically useful, divalent cations, demonstrated here using Ni as an example, compared to that of aluminosilicate and zincoaluminosilicate analogs.

Organic-free synthesis of zincoaluminosilicate zeolites from homogeneous gels prepared by a co-precipitation method.

Zeolites containing Zn in their frameworks are promising materials for ion-exchange and catalysis because of their unique ion-exchange capabilities and characteristic Lewis acidity. However, expensive organic compounds often required in their synthesis can prevent their practical uses. Here, a facile organic-free synthesis route for new zincoaluminosilicate zeolites having MOR topology, in which both Zn and Al are substituted in the framework, is demonstrated for the first time.

Synthesis of monodisperse organosilica nanoparticles with hollow interiors and porous shells using silica nanospheres as templates.

A versatile method for the formation of monodisperse, bridged silsesquioxane nanoparticles with hollow interiors and porous shells has been developed using silica nanospheres as templates. Tunable size and shell thickness, as well as high surface areas and large pore volumes of the hollow particles, allow for practical application of these nanoparticles in many fields.