NANO PORES


1.        What are Nano Pores?

Nano Pores are three-dimensional,crystalline solids, microporous and nanoporous with
well-defined structures that contain aluminum, silicon, and oxygen in their regular
framework; cations and water are located in the pores. The silicon and aluminum atoms are
tetrahedrally coordinated with each other through shared oxygen atoms. Nano Pores are
natural minerals and have void space (cavities or channels) that can host cations, water, or
other molecules. Because of their regular and reproducible structure, they behave in a
predictable fashion.

2.        Structure of Nano Pores materials.

One of the decisive characteristics of Nano Pores is their mesoporous structure. Nano Pores
are built up of tetrahedral building blocks (e.g. silicate or aluminate anions) that are linked
via common oxygen atoms to form a three-dimensional structure. The resulting cavities in
the Nano Pores materials can contain cations, such as sodium, potassium or calcium, usually
associated with some water of hydration.


                                                        
                                                                Part of the structure
                                                                with possible locations
                                                                of the cations.                                          





                                                                The micro-porous and
                                                                nano-porous molecular
                                                                of Nano Pores.





                                                                View along the c axis







                                                                      View of the channel perpendicular
                                                                      to the c axis.




                                                        
                                                                Projection along the c axis showing
                                                                the main channels.

                                        




                                                                View along the c axis showing the
                                                                van der Waals radii.



3.        Some of the Major Applications of Nano Pores.

Adsorption

Nano Pores are used to adsorb a variety of materials. This includes applications in drying,
purification, and separation. They can remove water to very low partial pressures and are
very effective desiccants, with a capacity of up to more than 25% of their weight in water.
They can remove volatile organic chemicals from air streams, separate isomers and mixtures
of gases.

Catalysis

Nano Pores can be shape-selective catalysts either by transition state selectivity or by
exclusion of competing reactants on the basis of molecular diameter. Nano Pores can also be
acid catalysts and can be used as supports for active metals or reagents. They have also been
used as oxidation catalysts. The main industrial application areas are: petroleum refining,
synfuels production, and petrochemical production.

Ion Exchange

Nano Pores can replace phosphates as water-softening agents. They do this by exchanging
the sodium in the Nano Pores for the calcium and magnesium present in the water.

4.        How do Nano Pores function as ion exchanger?

The framework aluminum and silicon are bound to each other through shared oxygen atoms.
The SiO4 units are neutral: Si+4 / 4 O- but the AlO4 results in a net negative charge: Al+3 /
4O- . The net negative charge is balanced by cations that are present during the synthesis.
These cations are highly mobile and can be exchanged for other cationic species.

5.        Are Nano Pores stable?

Nano pores are thermally stable to over 500 °C. Some are stable in an alkaline environment,
and some are stable in acidic media. They are also stable to ionizing radiation and can be
used to adsorb radioactive cations.

6.        What makes Nano Pores special when compared with other inorganic oxide materials?

The combination of many properties, among them: the microporous and nanoporous
character of the uniform pore dimensions, the ion exchange properties, the ability to develop
internal acidity, the high thermal stability, the high internal surface area. These make Nano
Pores unique among inorganic oxides.