Many companies that rely on silica gel are switching to aluminum oxide or alumina for its superior qualities. While many businesses feel more comfortable with silica gel, the advantages offered by aluminum oxide make it an option that should be considered. They wonder if making the switch is worth it. Before answering that question, it is important to understand why this bauxite derived material is becoming increasingly popular over silica.

Limitations of Silica

While silica has a higher sample load, it also has some limitations. For instance, it hydrolyzes at pH 8, temperatures greater than 40 degrees celsius, and in the presence of phosphate or carbon ions. Silica is also soluble in organic media, even at elevated temperatures. Furthermore, the siloxane bond becomes unstable when its pH is lower than 4.5.

Benefits of Alumina

Aluminum oxide is becoming increasingly popular because it acts as a weak ion exchanger. In other words, it can act as both an acid or a base. These amphoteric properties exchange a variety of ions over a broad pH scale. This gives it some of the most superior amphoteric properties around. In comparison, silica has limited ion exchange capabilities. Also, aluminum oxide overcomes the low pH instability of silica. This is because aluminum oxide is stable through the pH range of 2-13. Its stability is one of the main reasons people are choosing it over silica.

Aluminum oxide is also popular because of the way it reacts at different pH levels. For instance, at a neutral pH, this material’s surface will not have a negative charge and will not interact with charge bases via electrostatic interactions. At solvent pH levels, its surface will have a positive net charge. At higher pH levels, its surface will have a negative charge. The zero point charge for aluminum oxide occurs at pH 9.2, although this can be shifted slightly using buffers. There is no other material that provides you with such stability and versatility. Therefore, it can be used in a wide array of industries. For instance, it is currently used for pharmaceutical, biohazard, bioterrorism, toxic waste, environmental cleanup, research, manufacturing, and dehydration applications.

Aluminum oxide can offer more stability and versatility than the traditional silica gel because it can at as an acid or base and is stable at a broad pH range. Consider switching to this material if you are looking for a superior alternative to silica gel.