Regeneration of oil-laden silica gel

The negative influence of oil on silica gel is largely unknown, and there are no comparable tests that provide relevant data on this issue. This series of tests should therefore only be considered as a preliminary test to gain a rough insight into this topic. The adsorption of the oil-loaded silica gel is carried out in the same way as the loading in the bypass and regeneration mode. Here, however, about 2 wt% oil is mixed with the silica gel beforehand, i.e. 10g oil is added to 500g silica gel. The regeneration was carried out with 50g silica gel. The oil-free and oil-loaded silica gel are placed in the drying oven at 110°C for 2 hours each. The weight is then determined every 30 minutes to determine the water removal. The question for this test was: Does the oil-laden silica gel release less water and can the oil-laden silica gel be used again after regeneration?

Humidified silica gel

Humidified and oil-laden silica gel

Regenerated silica gel

Regenerated oil-laden silica gel

Conclusion

A clear effect can be seen as the oil reacts on the silica gel surface at 110°C and takes on a brownish tone. The reaction destroys the color indicator and the silica gel becomes unusable as an indicator of moisture.
If the oil-laden but already dried silica gel is moistened again, it is noticed that it can absorb less water.