organic silica gel

Desiccant Packs

There are several desiccant materials in use today. Below you’ll find information on each, with a short summary of strengths and weaknesses.

Montmorillonite Clay

Montmorillonite clay is a naturally occurring adsorbent created by the controlled drying of magnesium aluminum silicate of the sub-bentonite type. This clay will successfully regenerate for repeated use at very low temperatures without substantial deterioration or swelling. However, this property causes clay to give up moisture readily back into the container as temperatures rise.

Clay is a good basic desiccant that works satisfactorily below 120°F (approximately 50°C). Above 120° F, there is a possibility that the clay will give up moisture rather than pulling it in, so anticipated storage and transportation conditions should be considered. The upside to clay is that it is normally the least expensive desiccant per pound.

Clay is highly effective within normal temperature and relative humidity ranges. Its appearance is that of small gray pellets. Care should be taken to be sure that any low level impurities in the clay are not incompatible with the packaged product.

Silica Gel
Silica gel is silicon dioxide (SiO2). It is a naturally occurring mineral that is purified and processed into either granular or beaded form. As a desiccant, it has an average pore size of 24 angstroms and has a strong affinity for moisture molecules. The silica gel will pull in moisture at temperatures up to 220°F (105°C). As temperature goes above 100°F, the rate of moisture pickup will slow down but the silica gel will still work.

Silica gel performs best at room temperatures (70° to 90°F) and high humidity (60 to 90% RH) and will drop the relative humidity in a container down to around 40% RH. In the United States, silica gel is commonly used in food and pharmaceutical applications as only silica gel has been approved by the FDA for direct contact with these items.

As with clay, silica gel, with its wide range of pore sizes, has the capability of adsorbing compounds other than water. The relative order of adsorb ability is: water, ammonia, alcohols, aromatics, diolefins, olefins and paraffins. When the potential for multicomponent adsorption is present, expect the more strongly adsorbed compounds, such as water, to displace the more weakly held ones.

Indicating Silica Gel
Indicating silica gel is a silica gel bead or granule that has been washed with a concentration of cobalt chloride ( a heavy metal salt). The cobalt chloride is a deep blue color when it is dry and turns from blue to purple to pink as it becomes saturated with moisture. Typically, the color changes as the desiccant goes past 8% moisture levels (by weight) and indicates it is time to replace the desiccant.

The most typical use for an indicating silica gel is for a moisture sensitive product that will be inspected regularly as it gives a quick visual indication of how well it is doing. Because of the addition of cobalt chloride, indicating silica gel should not be used in contact with products for consumption such as food or pharmaceuticals.

The Dri-Box canister is packed with an indicating silica gel that is regenerable. Instead of replacing the desiccant inside, heating the canister will reverse the adsorbing action and allow the material to be reused.

Molecular Sieve
Molecular sieves are porous crystalline aluminosilicates, a synthetic desiccant that has a very strong affinity for moisture molecules. The distinctive feature of the molecular sieve structure, as compared to the other desiccants, is the uniformity of the pore size openings in the crystal lattice structure.

There is no pore size distribution with molecular sieves. As part of the manufacturing process, the pore size on the molecular sieve particles can be controlled. The most commonly used pore size is 4 angstroms (4A) although 3 angstroms (3A), 5 angstroms (5A) and 10 angstroms (13X) are available. This feature allows the selection of a molecular sieve product which can adsorb water, yet exclude most other molecules, such as volatile organics, which might be present in the package.

For example, Type 3A molecular sieve’s structure, with a 3 angstrom pore opening, allows moisture adsorption, but excludes most hydrocarbons. Type 4A molecular sieve has a slightly higher moisture capacity, but adsorbs molecules as large as butane. Type 13X molecular sieve has a different crystal structure from the types 3A and 4A, and has a pore opening of about 10 angstroms. This allows for the adsorption of a wide range of organic molecules as well as moisture.

The selective adsorption characteristics of molecular sieves can be useful when it is necessary to dry a package without removing other desirable compounds from the system. Molecular sieve can hold moisture to temperatures well past 450°F (230°C), and because of its high affinity for moisture, molecular sieve is able to bring the relative humidity in packages down as low as 10% RH.
The United States FDA has not approved molecular sieve for direct contact with consumable items, although in Europe molecular sieve is used with pharmaceuticals. Being man-made rather than naturally occurring, molecular sieve is slightly higher in cost per unit, but due to its extremely large range of adsorptive capabilities, it might often be the best value, especially in areas of low relative humidity.

Lack of government approval for the use of molecular sieves in food and drug packaging has limited its more widespread use. Independent testing suggests that molecular sieves meet government requirements. Presumably, however, the industry has been unwilling to fund the expensive testing required for government approval.

Is this brand of litter a good brand?

Okay so usually my mom buys Special Kitty clay litter, and this time she wanted to buy the Purina Yesterday’s News recycled paper litter, but I convinced her to buy this other stuff called Desert’s Sand. I was wondering if this is a good brand, and if it does everything it says it will. I smelled it (it was unused, of course) and it smelled like vegetables, so I guess that’s a good thing. Also, there’s a comparison chart on the back, and it seems that silica gel litter does about everything this litter does. Is silica gel generally cheaper? What is the best organic (inexpensive) brand on the market?

Desert’s Sand litter claims to have 360 percent more absorption than clay based litter. It also doesn’t have dust, so when you dump it no cloud. Desert’s Sand also claims to be low allergen, controls mildew and is biodegradable. It also has no toxic chemicals and has some clumping, but not much. Whatever you do don’t get pine or cedar litter because though it smells good and eliminates odor, cats HATE it. It turns to sawdust when it gets wet and then the sawdust gets stuck in their paws. It also probably doesn’t feel natural to them. At least with sand like litter it’s more natural feeling. As for Special Kitty, it doesn’t eliminate any odors and it has a lot of dust when you dump it. Silica gel litter costs about the same but is more expensive. But not too much more. Hmmm… organic cat litter? Have you tried Trader Joe’s “I ended up getting the Trader Joe’s pine pellets because they didn’t have any other kind and I really needed cat litter.Well this stuff is fabulous!!! Not only is it inexpensive but it lasts for a really long time without smelling. I used to used the cheap clay stuff and change it often. I found this worked much better than getting the clumpy scoopable stuff. I have two cats and one of them spends most of his days outside now, so that helps. But because these pine pellets never get stinky, I have to remember to change the litter…. I highly recommend it. If you want your cats to get used to the pellets, you can mix it with your usual cat litter at first.” But I don’t know if it’s like feline pine or not.

Silicium G5 Gel

[groupmage source="groupon" location=0 display=5]
[groupmage source="crowdsavings" location=1 display=5]

Cellfood by Lumina 1 oz. Cell Food Cellfood by Lumina 1 oz. Cell Food…

Cellfood Skin Care Oxygen Gel, 2-Ounce Jars $24.99 Introduction Cellfood Oxygen Gel is specially formulated to take advantage of the dramatic topical benefits of Cellfood. Our formulators have utilized specific high quality ingredients— each one known to be an exceptional skin rejuvenator— to create a skin gel that i…

Jason Natural Products Shampoo Biotin …

Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing $392.03 Sol-Gel Science presents the physical and chemical principles of the sol-gel process at a level suitable for graduate students and practitioners in the field. This book defines sol-gel rather broadly as the preparation of ceramic materials by preparation of a sol, gelation of the sol, and removal of the solvent. The sol may be produced from inorganic or organic precursors (e.g., nitrates or alkoxi…

Colloidal Silica: Fundamentals and Applications (Surfactant Science) $282.09 In spite of the apparent simplicity of silica’s composition and structure, scientists are still investigating fundamental questions regarding the formation, constitution, and behavior of colloidal silica systems. Colloidal Silica: Fundamentals and Applications introduces new information on colloid science related to silica chemistry as well as theoretical and experimental aspects of significant …

The Chemistry of Silica: Solubility, Polymerization, Colloid and Surface Properties and Biochemistry of Silica $395.40 Surfactants and Interfacial Phenomena Milton J. Rosen Bridging the gap between purely theoretical aspects of surface chemistry and the purely empirical experience of the industrial technologist, this book applies theoretical surface chemistry to understanding the action of surfactants in modifying interfacial phenomena. It surveys the structural types of commercially available surfactants and disc…