An innovative and highly accurate volumetric differential system has been designed and built at the University of Edinburgh for the measurement of gas adsorption in porous media.
Differently from conventional (single branch) volumetric apparatuses, differential systems measure adsorption by monitoring the pressure difference between two symmetric branches, a sample and reference side. Relying on the use a differential pressure measurement (as opposed to absolute pressure measurements) has the advantage of higher and constant accuracy across the entire range of pressure monitored. This is particularly relevant for accurate measurements of high pressure adsorption isotherms (for storage purposes or as experimental isotherms to validate molecular simulations, for example).
Despite the higher accuracy, differential systems are far less common than single branch version. Their use has been limited to measurements of equilibrium isotherms of weakly adsorbing molecule (H2, for example) but no use of these systems has been reported for measurements of equilibrium of strongly adsorbed components and for kinetic purposes.
Measurements of this type involve a number of challenges, especially if carried out at high pressure where non-ideality and non-linearity effects are no negligible anymore.
The current system is designed for measurements up to 270 bar with a differential pressure resolution of +/- 600 mbar and it is capable of temperature settings from cryogenic to 300 °C. Being a built-in-house apparatus, the system is also designed minimising the volumes allowing to carry out experiments with about 1/10 of the amount of material required from other common experimental techniques.
As an upgrade to other existing setups the current systems involves measurement of the temperature in 4 positions including a direct temperature measurement of the adsorbent and no simplifying assumption of symmetry of the volumes is used.
The project will focus on the development of novel experimental approaches for the measurement and interpretation of adsorption equilibrium and kinetics on a wide range of commercial and prototype materials (hierarchical zeolites, adsorbents with gating effect, polymer-based materials, shale rocks).
In addition, the successful candidate will be in charge of the design and commissioning of different variants of the existing setup, optimised (based on the experienced gained) to conditions relevant for specific industrial and/or research applications.
Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree. Further information on English language requirements for EU/Overseas applicants.
Tuition fees + stipend are available for Home/EU students (International students not eligible)