New reference materials support industrial zeolites
The National Institute of Standards and
Technology (NIST) has issued three new reference materials to support
researchers studying the properties of commercially important zeolites.
First described in the 18th century, zeolites have
seen increasing use in industry and commerce from cat litter to
industrial catalysts and "molecular sieves." Zeolites belong to class
of materials called alumino-silicates whose crystal structures form
highly porous, nanoscale "cages" that can filter and trap small
molecules. Naturally occurring zeolites are mined and widely used as
absorbents in products such as cat litter. Tailored synthetic zeolites
have a wide variety of more specialized applications, such as in
laundry detergents (where they replace pollution-causing phosphates),
and as catalysts in oil refineries. Because they can be designed with
pores that pass only molecules of a certain size and shape, zeolites
have excited considerable interest as molecular sieves for chemical
separations - they are used in oxygen generation systems for medical
oxygen, for example.
It is often extremely difficult to make precision
measurements of key chemical characteristics for zeolites because they
are ferociously hygroscopic. Humidity must be precisely
controlled--and specified--to make meaningful measurements of the
elemental content, for example. This has made it difficult to compare
experimental results between different labs.
To provide a common basis for research on three
widely used industrial zeolites, NIST has issued reference materials
for Zeolite Y (RM 8850), Zeolite A (RM 8851) and Ammonium ZSM-5
Zeolite (RM 8852). While these materials do not come with the
certified property values and uncertainty estimates furnished with
NIST Standard Reference Materials (SRMs), these RMs do provide a
common source of zeolite materials for measurement comparisons.
Reference and information values are provided for major and trace
element content, key atomic ratios, enthalpy of formation, unit cell
parameters and particle size distributions.
ChemLin offers different
instruments with which you can publish or refer to the appropriate web
pages, press releases, product news, appointments etc.
For your personal publication please use this form.
