Desiccants are compounds or agents that are used in facilitating low humidity environments by absorbing moisture content from the air. Some of the examples of desiccants include montmorillonite clay, silica gel, molecular sieves, etc. Desiccants are used in transport, storage or maintenance of materials and products to maintain a dry environment. Here is how you can select the right desiccant for your applications:
What do You Need to Know Before Selecting the Desiccant?
Usually there are four sources of water contamination in a closed container or package which desiccants are designed to combat:
- Water paper in the air inside the package,
- Moisture contained in the materials inside the package,
- Moisture in or on the walls of the package, and
- Entry of moisture into the package due to permeation or leakage.
When deciding on the proper desiccant, it should be known how much water vapor can be adsorbed by the desiccant at various relative humidity level.
How to Start the Selection?
First you should determine the conditions of maximum product integrity; the size and type of container used and the actual conditions such as temperature and relative humidity. In order to select the right desiccant, it is important to know the conditions surrounding the shipment and storage of the product. The container in which the product will be packaged, shipped, and stored is vital in determining how much of a particular desiccant is needed and in what packaging form.
What Size Desiccant Do You Need?
The size of the desiccant you would need depends on various factors. Some of these factors include size of the air space to be humidity controlled, the nature of the material in the package, the moisture barrier surrounding the package, the type of desiccant being used, the desired shelf life, the atmosphere conditions and the type of seal on the package. When you go to purchase desiccants from Bee Chems, the experts at the company will ask a plethora of questions to determine the above factors.
How to Choose the Right Desiccant?
Here is a comparison between some of the most popular desiccants in the market:
- Clay
Montmorillonite clay is the clay that is used as a desiccant. It is a naturally occurring, porous adsorbent that is mined and then dried for use as a desiccant. This clay can successfully regenerate for repeated use at very low temperatures. However, this property also causes the clay to release moisture into the container as temperatures rises, which can cause potential for moisture issues.
- Silica Gel
This is the most commonly used desiccant in the pharmaceutical industry. The substance has a unique structure, enabling it to adsorb a wide variety of chemical substances. Silica gel is most adsorbent with water and can adsorb up to 40% of its weight in water.
- Molecular Sieve
If your product will see a wide range of environmental conditions, a molecular sieve desiccant may be the best option for your packaging. Due to the uniformity of the pore size openings, the substance has a high adsorption capacity at low relative humidity. Unlike clay desiccants, molecular sieves don’t release moisture back at higher temperatures.
- Calcium Oxide (CaO)
Calcium oxide is a cost-effective desiccant that should be considered for products that will be stored or transported in areas with high temperatures. The substance is also known as quick lime is distinguished by its ability to adsorb a much greater amount of water at low relative humidity than other materials.
Looking to get Calcium Silicate? Bee Chems is your place to go. In addition to adsorbents and absorbents, the company also offers Colloidal Silica, Investment casting slurry systems, silica gel-sorbogel, activated alumina-actal, dew pouch-activated desiccant packs and various others.
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