PhD Studentship: Direct Air Capture - Process modelling and scaling up material production

Description

We face a climate change crisis, and it is now accepted that we not only need to dramatically reduce our greenhouse gas emissions, but that we also need to remove greenhouse gases from the atmosphere. The Forse Group in the Yusuf Hamied Department of Chemistry are working on “direct air capture”, an approach where sponge-like materials are used to capture carbon dioxide directly from the atmosphere. The traditional sponge materials for this process have issues including poor long-term stability and/or the need for very high temperatures (up to 900 ºC) to regenerate the sponges for reuse. 

To tackle these issues, the Forse Group recently pioneered a new approach to make carbon sponges. Starting with cheap and readily available activated charcoal, the team developed a “charging” method similar to the charging of a battery. This process charges alkaline hydroxide molecules into the porosity of the charcoal to enhance its carbon capture ability. These materials show promising direct air capture performance, and they are stable, cheap, and can be regenerated at low temperatures (~100ºC). The group’s breakthrough study was recently published in Nature in 2024 and was highlighted in over 100 news stories, including in the BBC, The Independent, and CNN.

Professor Scott’s groups in the department of Engineering have been working on various novel carbon capture processes, from the material through to the process scale. The power required by a DAC depends on the both the “sponge” and how it is integrated into a process, e.g. low capacity can be compensated for by a shorter cycle, high energy requirements can be offset by energy recovery strategies. Therefore, the process and material must be evaluated simultaneously.  DAC is limited by the energy input needed to regenerate the sponge. Using heat forces the process to use much more energy than is needed. The sponges developed offer unique opportunities to electrify the DAC process either through joule heating, or via electromediated desorption.  However, the route to large scale utilisation still needs to be fully explored. 

The next steps for the work involve tackling four challenges to realise the full carbon removal potential of the new charcoal sponges:

1. Improve the capacity of the activated charcoal, since the first generation of the material captures less carbon than rival materials (although there are significant benefits with the activated charcoal).
2. Establish methods to improve the effectiveness of the material in higher humidity air, since this will enable the material to be used in a wider range of climate zones.
3. Establish feasibility of scaling up materials to practical DAC systems. 
4. Design and optimise an engineered direct air capture system built around the new material.

To understand how best to deploy new carbon sponges in a real-world direct-air capture process, process modelling and optimisation work is required. A process modelling PhD studentship, jointly supervised between the Engineering and Chemistry Departments will seek to answer the following questions: (i) How much energy and cost can be saved with new carbon sponges, compared to existing approaches? (ii) Is it possible to operate a direct air capture process efficiently using waste heat or electricity for sponge regeneration? (ii) How sensitive is the cost of direct air capture to the sponge properties, including capacity and water competition? (iv) How sensitive is the cost of direct air capture to the environmental conditions, and in particular humidity? The process modelling work will inform the carbon sponge development work by another PhD student.

The University actively supports equality, diversity and inclusion and encourages applications from all sections of society.

*Funding will cover the student's stipend at the current Research Council rate and University Fees. The studentship will be funded for four years from October 2025.