Reusable Natural Bentonite Clay Desiccant

Reusable natural bentonite clay desiccant

Desiccant Performance

In terms of their capabilities and performance as desiccants, bentonite clay and silica gel have numerous similarities. Both are highly adsorbent materials. This means that even at full water vapor capacity, both remain dry and free-flowing, without any apparent change in size, shape or texture. And, both of these desiccants can be "reactivated" by oven-drying them to remove retained water vapor between uses.

They are also quite similar in terms of "unit" weight and relative adsorption performance. Desiccants are measured in "units" according to mili tary and industry specifications including MIL-D-3464 (U.S), DIN 55473 (Germany) and AFNOR NF H00-321 (France). The MIL and DIN specifications define a unit as the amount of desiccant that will, at a temperature of 25° C, adsorb 3 g of water vapor at 20% relative humidity and 6 g of water vapor at 40% relative humidity. By this standard, a unit of bentonite clay desiccant weighs about 33 grams, while a unit of silica gel weighs about 26 grams. Both will adsorb water vapor equivalent to between 30 and 40 percent of their unit weight. (Note: the AFNOR NF H00-321 specification defines a desiccant unit with 100 g moisture adsorption.)

Although the adsorption properties of bentonite clay and silica gel desiccants are comparable on a unit for-unit basis, tests show that bentonite clay offers higher adsorption capacity in the most common and relevant package conditions. The adsorption capacity of bentonite is substantial at low humidity levels and increases with increasing relative humidity. Silica gel behaves similarly, but becomes even more adsorbent at higher levels of relative humidity. At these higher humidity levels, its very high rate of adsorption can, at times, make silica gel more difficult to handle.

Parameters

• Particle size: 0.5-1.5 or 1-4(mm)

• Water content: less than 2%

• Moisture absorption rate: 20%-25%

• Wrapping film: tyvek, non-woven or OPP 

Packing details

Applications

• automobile parts

• aviation

• canned and bottle foods and drinks

• foods

• electronics

• electronic components (example: surface mount devices, integrated circuits, circuit boards, capacitors and resistors) used in dry pak per JEDEC J-STD-033

• engines

• textiles

• leather goods

• metals

• machinery