How does the performance of color-changing silica gel desiccant improve after regeneration?
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Color-changing silica gel desiccant can be regenerated to >95% of its initial performance value, although the specific restoration degree relies on the regeneration process, temperature management, and usage history.
1. Recovery of performance after regeneration
Under optimum conditions (e.g., oven heating at 100–120℃ for 1–2 h):
The adsorption capacity can be recovered to over 95% of the original performance, the colour can completely change from pink/red or green back to blue/orange and the indicator function is normal, the microporous structure is undamaged and the moisture absorption rate is close to that of a new product.
In laboratory and industrial applications, appropriately regenerated silica gel is often regarded as similar to a new product.
2. Key factors influencing the efficiency of regeneration
Factors and How They Affect Performance
Regeneration temperature: When the temperature is over 120℃, cobalt chloride will be oxidised and deactivated, resulting in irreversible colour recovery and adsorption capacity loss.
Heating Uniformity Excessive stacking or localised microwave overheating readily leads to particulate pyrolysis, which reduces the mechanical strength.
Moisture Absorption: If not addressed for a long time after saturation, moisture gets absorbed deep into the micropores resulting to incomplete desorption.
Number of Regenerations: After each regeneration, performance will reduce around 5%~10%. The reduction rate will increase after more than 5 regenerations.
Should the colour be grey, dark red or not become blue during heating, then regeneration has failed and the indication and some adsorption capabilities have been lost.
3. Recommendations for use after regeneration
Cool and Sealed Storage: Cool naturally in an oven turned off to prevent moisture absorption in heat.
Record Regeneration Numbers Performance monitoring should be increased after ≥5 regenerations, replacement after ≥10 regenerations.
Avoid Contamination: Contact with oil or organic materials prior to regeneration will result in irreversible pore blockage.
Practical tips: For moisture protection of cameras, hearing aids and electronic parts, it is advisable to put these into a desiccator for 24 hours after regeneration and to confirm that there is no condensation before putting them into use.
