Multi-stimuli Responsive Smart Hydrogels for Energy-Efficient CO2 capture

Carbon capture and storage (CCS) has widely been considered, both globally and in the UK, as a crucial part of global low carbon energy portfolio required to control the rise in global mean temperature below 2 degree C above pre-industrial levels. CCS is the only technology available that can achieve deep reductions in carbon emissions from both power generation and industrial processes in the short-to-medium term, with carbon capture representing the first and most costly single element of the whole CCS chain. Aqueous amine scrubbing at its various forms is currently the best available technology and has been demonstrated at various scales. However, despite the intensive developments at various scales over recent years, its large energy penalty, equivalent up to 20% of a typical power plant output, still remains a major performance barrier. Clearly, new cost-effective and energy-efficient capture concepts leading to substantial reductions in energy penalty need to be explored. 

Prompted by recent research in areas of thermo-responsive hydrogels which has led to successful applications in advanced target separations, this proposal aims to develop a new concept of CO2 scrubbing with photo-thermo dual-responsive smart hydrogels, which is expected to be substantially more energy-efficient than amine scrubbing. In this new capture concept, functionalised smart hydrogels, which are mechno-chemically responsive to both heat and sunlight radiation, are used as the absorbent for CO2 capture. The rapid response of the hydrogels to heat and/or light combined with the induced pH swing can facilitate rapid sorbent regeneration/CO2 recovery under much milder conditions. It is anticipated that the temperature swing range for sorbent regeneration can be narrowed to as low as 20-30 degree C, from ca. 70-90 degree C for amine scrubbing. More importantly, the photo-thermo dual-responsive hydrogels-based CO2 capture could potentially make it possible to make use of low grade heat and/or sunlight or solar radiation to drive the CO2 capture system. The major objectives include:
(i) To develop photo-thermal dual responsive hydrogels with high reversible CO2 absorption capacities and favourable volume phase transition behaviours;
(ii) To characterise the physicochemical properties and the CO2 absorption/desorption characteristics of different dual-responsive hydrogels under various temperature swing and light radiation conditions to identify the best-performing smart hydrogels for CO2 capture.
(iii) Once the optimal hydrogels have been identified, scale-up production of the hydrogels will be carried out to perform cyclic CO2 scrubbing tests with the smart hydrogels, using the purpose-designed lab-scale film and column absorbers under different thermal swing conditions with and without light radiation at variable intensities. The test results will be used to assess the feasibility of this new CO2 scrubbing concept to facilitate further development and scale-up of the technology.

Planned Impact

The novel research idea has received the strong support of leading industrial partners relevant to the research field, including a UK power generator (Uniper Technologies Limited), a world leading technical consultancy firm (WSP | Parsons Brinckerhoff) and a world leading company in speciality chemicals and sustainable technologies (Johnson Matthey). 
This project aims to develop and assess a new concept of CO2 capture that is much more energy efficient than the state of art PCC capture technologies. In addition, the novel CO2 capture process can be driven by low grade heat and/or light and this makes it suitable for applications to not only the power sector, industrial processes but also direct air capture. The successful delivery of the proposed project objectives will enable the research team and partners to lead the future demonstration and commercialisation of this game-changing capture technology. Therefore, in the longer term, this will bring new job and export opportunities to the UK, benefiting the UK society and the general public irrespective of whether the UK adopts CCS in the future.

The know-hows acquired in this project for the smart hydrogels will also be of direct benefit to researchers in the areas of CCS, nanomaterials, nanocomposites and polymers chemistry, power generation and energy industries, energy policy makers/regulators, environmental organisations and government departments such as Department for Business, Energy & Industrial Strategy. In addition to the Research Fellow appointed on the project, other researchers and PhD students within the Doctorate Training Centres in CCS and Cleaner Fossil Energy and the Energy Technology Research Institute of the University of Nottingham can also benefit from the multidisciplinary research project through attending the organised project meetings, seminars and workshops. These researchers, whether directly or indirectly trained on the project, will provide high quality expertise for the UK CCS, hydrogels, nano-materials, nano-composites and polymers chemistry research communities and energy industry, and contribute to leading further demonstration and deployment of the novel capture technology in the UK and other parts of the world.

The project team will commence various activities of engagement with academic colleagues, UK CCS network members and carbon capture technology developers. The dissemination of the research outcomes will be achieved through 6-monthly project meetings with the participation of industrial partners and other key CCS stakeholders, presentations at national and international conferences, UK CCS research network meetings, and open access journal paper publications. High impact journals such as Energy & Environmental Science, Environmental Science & Technology and Chemical Science and high quality international conferences such as the American Chemical Society International Conferences and RSc Faraday Discussion Meetings will be targeted for the publications and presentations of the first results of this feasibility study.

Communications with industrial and other stakeholders will be also pursued via 1) networking activities with the existing national/international project partners of the project team and DTCs; Website; close engagement with the UK CCS Research Centre and the Nottingham-led DTCs in CCS and Cleaner Fossil Energy, in particular, making presentations at the UK CCSRC’s bi-annuals and DTC’s Winter Conferences; and Exhibition and demonstration at Nottingham’s public engagement event (‘Wonder 2017’ and/or ‘Wonder 2018’).