Modelling of flow and sorption processes in personal protective respirators

   Department of Chemical Engineering

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  Prof John Chew, Prof Semali Perera  No more applications being accepted  Funded PhD Project (European/UK Students Only)

About the Project

The University of Bath is inviting applications for the following fully funded PhD project, ideally commencing before April 2022. Later start dates may be possible.

Funding is available to candidates who qualify for ‘Home’ fee status. Following the UK’s departure from the European Union, the rules governing fee status have changed and, therefore, candidates from the EU/EEA are advised to check their eligibility before applying. Please see the Funding Eligibility section below for more information.

Project team: Prof John Chew (Lead) and Prof Semali Perera (Co-supervisor)

Informal queries should be directed to Prof John Chew - [Email Address Removed]


Applications are invited for a PhD studentship to study the transport mechanics of gases in personal protective respirators. Military personnel and First responders such as Police and Emergency Services rely on their personal protective equipment (PPE) to protect them from a wide variety of threats. In particular, their respirators must provide protection against not only traditional chemical agents, but also against a wide range of toxic industrial chemicals that may be accidentally released. Respirators generally use filters based on chemically impregnated activated carbon or other sorbents that remove toxic gases and vapours from breathing air either by direct physical sorption or by chemisorption. Physisorption is useful in removing many organic vapours but is less effective against inorganic gases where chemisorption is used. To provide broad spectrum protection against a wide variety of gas and vapour challenges, military/ personal protection filters generally use carbon impregnated with a number of metal salts. High concentration levels of impregnation may compromise physisorption capacity and impregnation chemistry that is effective for some challenges may interact undesirably with others. As a consequence, a number of compromises have to be made in filter design and this PhD research aims to provide an improved understanding of the sorption processes in personal protection filters. In particular, adsorption or chemisorption tends to concentrate on the adsorption capacity of the sorbent, the total amount the sorbent can retain or react to at a given pressure or partial pressure. But, materials of equal capacity do not necessarily provide equal protection in a filter use scenario with kinetic flow. This project will investigate the links between material properties (e.g. particle size distribution) and gas adsorption capacity with the protection of the filter with kinetic flow. This is further complicated by competing processes, e.g. water vapour uptake and chemical reactions with some chemicals. For example, NO2 gas retention often culminates in the generation of other NOx species. The expanded understanding from this research project of how the NO2 is converted in the filter will be applicable to other carbon-based NO2 filters used for pollution or emission filtration. The successful candidate will be trained in relevant methods and procedures, including access to commercial CBRN filter design and test results, numerical modelling, gas adsorption characterisation, validation model against industrial data and advanced analytical characterisation methods. 

Candidate Requirements:

• Have a First Class Honours MEng degree from the UK (or equivalent qualification from international Institutions) in Chemical Engineering or a relevant subject area.

• Possess a reasonable understanding of numerical modelling and adsorption technology.

• Be highly self-motivated, with capacity to learn and develop computer programming and predictive modelling techniques.

• Have well-developed and positively collaborative interpersonal skills.

• Have an ability to deliver technical reports and communicate findings.

• Have organisation and project management skills

• Be willing to travel and work in industrial / community support settings.


Formal applications should be made via the University of Bath’s online application form for a PhD in Chemical Engineering. Please ensure that you state the full project title and lead supervisor name on the application form.

More information about applying for a PhD at Bath may be found here:

Fee status:

Information may be found on our fee status guidance webpage, on the GOV.UK website and on the UKCISA website


Adsorption; Gas purification; Modelling; Face mask; Chemical Engineering


Funding Notes

This studentship includes full funding for ‘Home’ tuition fees, a stipend (£15,609 per annum, 2021/22 rate) and research/training expenses (£1,000 per annum) for up to 3.5 years.
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