Measuring Vapor and High Pressure Gas Sorption with Gravimetric Analyzers

Interview conducted by Mychealla RiceOct 4 2018

High-pressure adsorption is of significant interest for a wide range of applications. In this interview, Dr. Mark Roper, Sales and Marketing Director from Hiden Isochema talks to AZoM about the revised range of XEMIS high accuracy gravimetric sorption analyzers designed for a wide range of gases and vapors at high pressures.

Please tell us about the XEMIS series of instruments?

Hiden Isochema has a long history in the design and development of gravimetric gas sorption analyzers, such as the IGA and IGAsorp. The XEMIS includes a new type of microbalance and was launched in 2013, with an impressive list of XEMIS customers and academic publications already.

Recently, we refined the instrument range and launched a series of models, each focused on a specific measurement type. The XEMIS series are high accuracy gravimetric sorption analyzers, operating to 200 bar, with toxic, corrosive and flammable gases and vapors.

Please tell us about the features and benefits of each model?

The XEMIS-001 is designed to measure pure gas sorption up to 2500 psi (170 bar) on a range of materials and with gas species such as carbon dioxide, hydrogen, and methane. XEMIS-002, meanwhile, is a single component pure gas and vapor sorption analyzer.

Compatible vapors include water, alcohols, hydrocarbons and aromatics. XEMIS-003 is a versatile gas sorption analyzer, which also operates in a flowing mode and therefore can be used for TGA-type measurements as well as isotherms. XEMIS-100 adds single component vapor sorption to the features of the XEMIS-003. All XEMIS models can be used with corrosive and toxic gases, such as NOx and SOx.

How do the XEMIS instruments compare to other models on the market? What sets them apart?

XEMIS instruments have a unique combination of features – being able to operate at both very low and high pressures, and with corrosives. Also, the gravimetric technique is more accurate than the main alternative, the manometric technique, which is often used to measure gas sorption at high pressures.

Sample size is another point – no other instrument can measure high-pressure gas sorption accurately with sample sizes down to a few milligrams, yet novel materials being synthesized for the first time are often only available in very small quantities. This makes the XEMIS invaluable to researchers working on new materials such as metal-organic frameworks (MOFs).

The XEMIS range is compatible with flammable, corrosive and toxic gases and vapors. What applications will benefit from this?

There are many applications that aim to reduce the harmful impact of toxic species on humans and the environment. Examples include the removal of atmospheric pollutants, sour gas sweetening, refrigerant handling, and the development of personal protection equipment. Research into novel adsorbents for use in such applications is both important and highly topical, and the XEMIS series will play a crucial role in this.

Image Credit: shutterstock.com/trancedrumer

With the widest controllable pressure range of any gravimetric sorption analyzer, what opportunity does this open for a lot of applications?

It’s actually more a case of versatility – now one instrument can be used to characterize materials using both gases at high pressure and vapors requiring very low pressures. Up to now, this may have required several instruments, so the XEMIS has proven to be very attractive to researchers wishing to accurately characterize a novel material over a very wide range of conditions.

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The XEMIS instrument can perform high accuracy measurements with small sample sizes. What applications will benefit from this?

The XEMIS again offers flexibility. Novel materials are commonly synthesized in small quantities, so the XEMIS allows these “research scale” samples to be characterized without compromising accuracy. Also, the less sample required for gas adsorption measurements, the more there is for other, potentially destructive, characterization techniques.

If larger samples are required – for heterogeneous natural materials, for example – the capacity of the XEMIS microbalance is 5 grams. Increasing the sample size is therefore no problem, but the point is that the flexibility is there.

What does the new and improved range of XEMIS instruments mean for the future?

The XEMIS series is the latest addition to our range of gravimetric instruments and demonstrates our commitment to the design and development of new sorption instrumentation of the highest quality.

The XEMIS makes the gravimetric technique available for a wider range of applications and allows research to be performed that simply couldn’t have been done before.

Where can our readers go to find out more?

For more information visit our website, request a brochure or call us to speak to one of our experienced product specialists to discuss how XEMIS could work for your application.

About Dr Mark Roper

Dr Mark Roper is Sales and Marketing Director for Hiden Isochema, and is based at the company headquarters in the UK. Mark obtained a MSci(Hons) in Chemistry from the University of Nottingham, and went on to study for a PhD in Physical Chemistry at the same institution. He gained his PhD in 2004, with a thesis on the structure and bonding of self-assembled adsorbed monolayers of thiolates on gold substrates.

Mark then joined Hiden Isochema as a Systems Engineer, before becoming an Application Specialist in 2007, focused on gravimetric gas and vapour sorption instrumentation for characterising the chemical and physical properties of materials.

In 2009, he was promoted to his current position, since when Hiden Isochema have led the introduction of several new product ranges, including the next generation microbalance technology featured in the XEMIS series of gravimetric sorption analysers, and the ABR series of automated breakthrough systems.