We carry both granular and beaded silica gel
desiccant in bulk quantities. Custom sized orders
available.
Silica gel is a granular, porous form of
silica made synthetically from sodium
silicate. Despite the name, silica gel is a
solid. It is usually distributed in the form
of beads, which are packaged in a
semi-permeable packet.
Silica Gel is a highly activated adsorbent,
furnished in a wide range of mesh sizes to
suit various industrial applications. It is
non-corrosive, odorless, tasteless, non-toxic,
and chemically inert. It is a highly porous
form of silica, with an extremely large
internal surface area. The silica gel does not
undergo any chemical reaction during
adsorption and does not form any by products.
It is non-deliquescent and will not change its
size or shape. Even when the silica gel is
water saturated, it remains dry and
free-flowing.
Silica Gel has a very strong affinity for
water and will adsorb it in preference to most
other substances. It is also a good adsorbent
for HC1, gasoline-range hydrocarbons, CO2,
C12, sulphur and nitrogen compounds,
aromatics, and many others. Silica Gel is in
wide use in many industries for a myriad
number of applications where a high capacity
desiccant or selective adsorbent is required.
Silica gel was patented by chemistry professor
Walter A. Patrick at Johns Hopkins University
in 1919. Prior to that silica gel was already
used in World War I for the adsorption of
vapors and gases in gas mask canisters and
before that the substance was in existence as
early as the 1640s as a scientific curiosity.
In World War II silica gel was indispensable
in the war effort in keeping penicillin dry,
in protecting military equipment from moisture
damage, as a fluid cracking catalyst for the
production of high octane gasoline and as a
catalyst support for the manufacture of
butadiene from alcohol, an integral part of
the synthetic rubber program.
Silica gel has a very high porosity, around
800 m²/g, allows it to adsorb water
readily, making it useful as a desiccant
(drying agent). It can reduce the relative
humidity in a closed space to around 40%. Once
saturated with water, the gel can be
regenerated (dried) by heating it to 150°C
(300°F) for 1.5 hours per liter (about 1
dry quart measure or about 30oz weight) in a
thick-walled Pyrex dish. Silica gel is
non-toxic, non-flammable and chemically un
reactive.
However, some of the beads may be doped with a
moisture indicator. While non-doped silica gel
is non-toxic, the chemicals used to dope it
can be toxic and are the reason most silica
gel is labeled as dangerous or poisonous when
eaten. Synthetic amorphous silica, which is
what silica gel is, does not cause silicosis.
In layman's terms: In leather products and
foods like pepperoni, the lack of moisture can
limit the growth of mold and reduce spoilage.
In electronics silica gel prevents
condensation, which might damage the
electronics. If a bottle of vitamins contained
any moisture vapor and were cooled rapidly,
the condensing moisture would ruin the pills.
You will find little silica gel packets in
anything that would be affected by excess
moisture or condensation.
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