What is the Difference Between Colloidal Silica and Reactive Silica?

The main difference between colloidal silica and reactive silica lies in their structures and reactivity. Here are the key differences between the two:

1. Structure: Colloidal silica is a suspension of silica particles in a liquid phase, with an amorphous, nonporous, and typically spherical structure. Reactive silica, on the other hand, is a non-polymeric form of silicon that dissolves in water.
2. Reactivity: Colloidal silica is highly non-reactive. Reactive silica is a very weak acid that dissolves in water and tends to undergo polymerization and other chemical reactions.
3. Presence in Water: Both colloidal silica and reactive silica can be found in water supplies. Colloidal silica has a glass-like structure that can damage surfaces, glassware, and fixtures, while reactive silica can cause scaling and other issues in water systems.
4. Removal: Ion exchange water softener systems can effectively remove reactive silica by dealing with its negative charge. However, these systems cannot effectively remove colloidal silica. Reverse osmosis water purification systems can remove both molecules and ions, effectively dealing with both reactive and colloidal silica, but some pre-treatment is still required for colloidal silica.

Comparative Table: Colloidal Silica vs Reactive Silica

The key difference between colloidal silica and reactive silica is that colloidal silica is the polymeric form of silicon, whereas reactive silica is the non-polymeric form of silicon. Here is a table summarizing the differences between colloidal silica and reactive silica:

Colloidal silica is more like a solid than a dissolved ion, while reactive silica is dissolved silica that is slightly ionized. Reactive silica is an anion in terms of balancing a water analysis and is used in RO projection programs. Both colloidal and reactive silica are present in water supply, but they have different characteristics and behaviors.