Efficient silica gel for reliable moisture absorption
PORESPHERE™ A White is a high-quality, densely porous silica gel specifically designed for highly efficient water vapor absorption. Thanks to its precisely engineered pore structure, it reliably and permanently binds even the smallest amounts of moisture. This ensures dry and stable environmental conditions in a wide variety of applications.
PORESPHERE™ A White silica gel is ideal for applications where low residual moisture and high chemical purity are crucial – for example, in protecting sensitive electronics, in laboratory systems, in food storage, or in the long-term preservation of pharmaceuticals. Its high absorption capacity actively contributes to significantly improving the product quality and shelf life of sensitive materials.
Since PORESPHERE™ A White contains no color indicator, the material remains chemically pure and is approved for direct contact with food. However, alternative measurement methods should be used to monitor moisture saturation and ensure optimal drying.
Microstructure and pore structure
Adsorption behavior
Regeneration
PORESPHERE™ A Weiss is a synthetically produced, amorphous silica gel with a densely porous type A structure. The irregular arrangement of silicon and oxygen atoms results in a network of extremely fine pores (0.2–12.5 nm), creating a very large specific surface area of several hundred square meters per gram.
These fine pores enable efficient moisture absorption, while the uniform pore distribution ensures consistent adsorption even at low humidity levels. The dense pore structure and high adsorption capacity make PORESPHERE™ A White ideal for industrial drying, the storage of sensitive materials, and all applications requiring reliable moisture protection.
PORESPHERE™ A Weiss features a highly hydrophilic surface and a unique, densely porous microstructure that selectively binds water molecules while minimizing the adsorption of nonpolar substances. This property makes it ideal for applications requiring very low residual moisture without affecting other gases or substances.
Adsorption mechanism
Moisture adsorption in PORESPHERE™ A White occurs through a purely physical process (physisorption). Water molecules are bound to polarized silanol groups on the surface of the silica gel via van der Waals forces and hydrogen bonds. These silanol groups, with their partially negatively charged oxygen and partially positively charged hydrogen atoms, attract polar water molecules. The dense pore structure of the type A silica gel further enhances this hydrophilic effect, as increasing surface area provides more silanol groups for binding water molecules.
Regeneration
Since the adsorption process is a physical and reversible process, PORESPHERE™ A White can be regenerated by heating to release the adsorbed water. Regeneration at 140 °C ensures complete moisture removal, thus extending the lifespan of the silica gel and maintaining its performance.
Temperature dependence
| Temperatur / C° | Beschreibung |
|---|---|
| < 20 | Maximale Adsorptionskapazität, Feuchtigkeitsaufnahme langsamer |
| 20 – 80 | Feuchtigkeitsaufnahme nimmt stetig ab, Adsorptionskapazität verringert sich |
| > 120 | Prozess kehrt sich um, gebundene Feuchtigkeit wird für die thermische Regeneration freigesetzt |
Dependence on humidity
| Relative Luftfeuchtigkeit RH / % | Beschreibung |
|---|---|
| < 20 | Effektive Adsorption von Wasserdampf, auch bei niedriger Luftfeuchtigkeit |
| 20 – 80 | Stetige und effiziente Adsorption, mit optimaler Leistung. |
| > 120 | Adsorption verlangsamt sich, da die Poren gesättigt sind und die Kapazität erreicht wird. |
The adsorption of water molecules in silica granules is a reversible physical process known as regeneration. PORESPHERE™ A White can be regenerated by heating the granules at 140 °C for several hours. Temperatures below 100 °C are insufficient, while temperatures above 180 °C can damage the pore structure. Various regeneration methods are available depending on the application and purity requirements.
Three regeneration methods are possible:
Microwave/IR regeneration
Thermal regeneration
Vacuum regeneration
