Sustainable Adsorption Measurements: How to Preserve Helium

Introduction

To generate accurate gas sorption data using the conventional static volumetric methods, it has been traditionally necessary to introduce a non-adsorbing gas such as helium prior to every analysis. Helium is used to measure void volumes (free space) of the sample cell, apply gas non-ideality corrections, and define void volume warm and cold zones. While the use of helium for measuring void volume in gas sorption measurements has been commonplace, its scarcity and price has researchers looking for alternative accurate ways of obtaining the same high-quality data.

Helium is found as a byproduct of decaying uranium and fossil fuels, sources that are extremely limited around the world. In fact, the largest helium reserve is expected to be depleted by 2025. Helium is mined along with natural gas using a drill rig. Initial purity is typically only around 50%, so it must be purified using an extensive scrubbing process to obtain the ultra-high purity helium required for gas sorption measurements. Both the scarcity and the purification process have contributed to rising helium costs and limited helium supply worldwide. 

In order to eliminate the need for helium and allow for a more sustainable and cost-effective measurement technique, the Anton Paar Nova series instruments have the ability to perform analyses in NOVA (NO Void Analysis) mode.