Exploring the feasibility of volatile desorption studies by means of a quartz crystal microbalance with an integrated micro-heater

In this work the ability to perform desorption studies by using a micro-thermogravimetric device is demonstrated. The instrument consists of an oscillating quartz crystal microbalance with an integrated micro-heater that might turn out to be extremely useful in the study of the desorption of volatile com- pounds from refractory materials. The experiment here discussed has been performed by studying the release of adsorbed water from clay. Clay has been principally chosen because it is a material known for its ability to desorb and subsequently re-adsorb water at low temperatures and it might be considered a test mineral for a large number of applications, from first guess analysis of agricultural soil to quick inspection of materials of planetological interest (e.g., asteroid regolith). Results show that the device can be in stable operative conditions at 100 o C with 0.5 W of power supplied, allowing to measure the amount of desorbed water. In particular, as expected, it has been possible to assess that the desorbed water amount depends upon the working temperature, being less than 3 wt.% at 70 oC and about 5 wt.% at 90 oC.