Activated Alumina and Silica Gel

Activated alumina is a kind of desiccant but it cannot be directly used for absorbing moisture like silica gel. The purpose is entirely different for activated alumina. However, the internal structure of this substance is similar to silica gel desiccants. It is a porous substance.

Activated alumina can be used for water treatment or water purification. It is one of the main applications of this item. It can be used either in the beginning process of water purification or in the final process. Activated alumina has the capability to absorb the contaminants. Instead of filtering it, they are absorbed.

Water purification companies are using activated alumina as one of the main ingredients in their entire processes. The capability to absorb contaminants by activated alumina is depended on the characteristics of it and the quality of the water. Instead of filtering, they are absorbing the waste elements, so the chances are high to change it often.

Activated alumina can be regenerated like silica gel. But the process of regeneration is different. Silica gel can be regenerated by heating it. Once the moisture is vapored, silica gel can come back to its initial mode. It may get the full ability to absorb moisture as before. But activated alumina is different.

To regenerate activated alumina, we need to use strong acid and base solutions. It is not desirable to store inside the home. And it is not easy to handle also. This is one of the main drawbacks of activated alumina. But for industrial purposes, it can be stored in a separate place.

Silica gel is very popular among normal people, not like activated alumina. Because activated alumina is mainly used for industrial purposes and silica gel can be seen everywhere. It is familiar. Along with new shoeboxes, or with a new laptop bag we can see it.

Desiccants and Silica Gel

Desiccants are always considering as a perfect partner to keep along with for moisture-sensitive products. In the pharmaceutical industry, the most commonly used desiccating materials are silica gel, molecular sieves, and clay minerals. They can be incorporated into sachets, canisters, cards, or maybe into bottle closures.

Like excipients, these desiccants show humidity-dependent sorption/desorption behavior. However, their sorption capacity is far above typical excipients. This allows them to perform effectively in a much lower amount relative to drug products.

The overall moisture absorption capability of the desiccants are often calculated from the weighted sum of the moisture sorption isotherms of the active pharmaceutical ingredient (API), excipients, and desiccant. Use of desiccant isn't advised in cases where high levels of unbound water should be maintained for product performance (e.g., gelatin capsule shells).

We all are familiar with small silica gel packets. In our daily life, we are meeting those tiny packets from many places such as along with our new pair of shoes, inside our laptop bag, in a tablet container, along with the pregnancy kit, ...etc.

Usually, we will not keep these tiny silica gel packets once we opened the shoebox or laptop bags. But once we are familiar with the advantages of silica gel, we will never throw it. It has a good capability to absorb moisture from the surroundings. That is why the manufacturers are keeping it with their new products to avoid damages due to excess moisture.

We can use silica gel packets along with our food items also. There is a specific product named oxy-guard, which can keep along with the food products. Oxy-guard is an oxygen absorber. It can absorb oxygen from the food items such as bread, coffee beans, dried nuts, ...etc and keep them fresh for a long time.