Sterlitech™
Silver Membrane Filter: Frequently Asked Questions
Q. What is
the shelf life of silver metal membranes?
Q. What if my membrane is slightly
discolored?
Q. What NIOSH Standards are Silver Membranes
specified for?
Q. What are the advantages of silver
metal membranes over conventional membranes?
Q. Can silver metal membranes be cleaned?
Q. What are the specifications for the
silver metal membranes?
Q. What are your standard lead times?
Q.
What is the shelf life of silver metal membranes?
A. There is no shelf life for the silver membrane. However,
the formation of extraneous compounds is possible over time.
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Q.
What if my membrane is slightly discolored?
A. Although the silver metal membrane is 99.97% pure silver, the
formation of extraneous compounds is possible over time. For example,
silver can become tarnished, especially when the environment contains
certain emissions as described below. To minimize contamination
of the membrane, leave it in sealed packs. Silver compounds may
form on the surface which are primarily cosmetic imperfections and
do not affect the pore structure or membrane filtration performance.
Examples of colored compounds that can form on the surface of the
silver metal membrane are:
• Ag2S (black)
• Agl (yellow)
• Ag3PO4 (yellow)
• Ag2CrO4 (dark red)
• AgCl (dark brown)
• Ag2O (dark brown)
• AgBr (light yellow)
The most common compounds
that form on the silver metal membrane are Ag2S and AgCl. AgCl is
a photosensitive salt that can be removed by flushing the membrane
with an ammonia solution. Typically, just a brief soak or dip in
the ammonia solution will dissolve AgCl. Ag2S is a very stable compound
and is very difficult to remove from the membrane without altering
the structure. A flush with methyl or ethyl alcohol can be used
to remove some of the other compounds.
These compounds should not be confused with the natural grayish
white appearance of the silver metal membrane surface. This appearance
is due to the microporous structure of the media which reflects
light in a manner different than polished silver. The slight difference
in color between the two sides of the membrane is due to the manufacturing
process and is most noticeable on 3 and 5 micron pores sizes.
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Q. What NIOSH Standards are Silver Membranes
specified for?
A. See the Silver Membrane
Applications page for more details.
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Q. What are the advantages of silver
metal membranes over conventional membranes?
A. Sterlitech™ Silver Metal Membranes are 99.97% pure, thus
unique in their ability to withstand extreme chemical and thermal
stress, making them ideal for applications involving aggressive
fluids and/or high temperatures. In addition, the purity of the
membranes enables users to easily exclude and account for the few
chemicals that react with silver, thus making test results and filtering
operations more precise than available through traditional membranes.
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Q. Can silver metal membranes be cleaned?
A. Click
here to view the silver metal membrane cleaning guidelines.
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Q.
What are the specifications for the silver metal membranes?
A. See our section on benefits and features
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Q. What are your standard lead times?
A. We carry most diameters and pore sizes of Sterlitech™ Silver
Metal Membranes in stock and will generally ship within one or two
days.
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Sterlitech™ Silver Membrane pricing
chart.
Silver membrane application examples.
Silver membrane benefits and features.
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