Utilising Non-Recyclable Waste for Effective Carbon Capture

Project Description

An energy-driven economy and growing demand through population expansion have consumed substantial fossil fuels, leading to an exponential increase in carbon dioxide (CO2) concentration in the atmosphere. CO2 is the primary driver of climate change and, hence, global warming and ocean acidification, affecting the entire world’s ecosystem. Rising CO2 concentration in the atmosphere leads to various environmental consequences, such as rising temperatures, extreme weather events, and sea level rise. Regarding ocean acidification, the consequences are far-reaching and pose significant threats to marine organisms and ecosystems, including reducing the growth of coral reefs, shellfish and phytoplankton. In addition, this change in ocean chemistry can affect non-calcifying organisms, such as fish’s ability to detect predators. Therefore, developing a green, simple, cost-effective CO2 capture method has become a priority.

In order to phase out fossil fuels and the associated CO2 emissions, non-recyclable solid waste has been converted into energy using various thermal decomposition processes, such as combustion and gasification, reducing landfilling. Landfilling non-recyclable municipal solid wastes has several environmental consequences, such as groundwater and soil contamination with heavy metals, greenhouse gas emissions and resource depletion. Waste disposal represents a missed opportunity for energy conservation and a more sustainable approach to waste management. For example, Subcoal is a commercial solid biomass fuel from non-recyclable paper and plastic waste. Other than direct use in waste-to-energy processing, pyrolysis can be carried out to generate bio-oil, a medium calorific fuel gas and a solid black residue known as biochar, which has gained attention as an adsorbent material for CO2 due to a tuneable and functionable internal surface area, low cost, thermal stability, microporosity/mesoporosity and controlled composition.

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The industrialisation of non-carbon adsorbents, such as zeolites and metal-organic-frameworks, is still challenging due to their moisture sensitivity, operating conditions sensitivity, and complex/expensive manufacturing. Regarding carbon adsorbents, most studies have used biochar derived from wood waste, agricultural residues, animal manure and aquatic plants. Unlike non-recyclable municipal solid wastes, many of these biomass sources have a minimal environmental impact or are beneficial as animal feed, fertilisers and environmental remediation.

Aim and Objectives

This project aims to produce customisable biochars with a defined pore structure from Subcoal for CO2 sequestration after modifying the biochar’s internal structure with CO2 adsorption sites. Furthermore, the surface functional groups and adsorption capacity on the Subcoal biochar will be optimised using unique activation methods to obtain an effective adsorbent for CO2 capture. The biochar will be obtained from Subcoal pyrolysis as a cost-effective and renewable adsorbent. As a result, it links directly with the UN’s Sustainable Development Goals 3, 6, 13, 14, 15 and 17.

The project will progress through four work packages over three years: (1) Pre-treat the biomass, synthesise and activate biochar followed by characterisation of the raw and activated biochar to assess the pore structure, specific surface area and thermal stability; (2) Functionalise the biochar surface with amine functional groups, then characterise the functionalised biochar using a Fourier Transform Infrared spectroscopy, and Energy-dispersive X-ray spectroscopy; (3) Carry out CO2 adsorption experiments using a Thermogravimetric Analysis with an integrated reactor cell at different temperatures and CO2 inlet concentration, and incorporate a refined biochar material into a Direct Air Capture environment; and (4) Conduct an integrated Life Cycle Assessment and Technoeconomic Assessment using OpenLCA to assess the value in use of biochar from non-recyclable waste as effective CO2 adsorbent. Regarding collaborating with industry, the N+P Group, a waste-derived alternative fuel production company, will supply the Subcoal biomass.

Graphical Abstract


In addition to the Research Training provided by Panorama, the student will be trained on materials characterisation technologies such as Fourier Transform Infrared Spectroscopy, Thermo-gravimetric Analysis, Elemental Analysis,  Powder X-ray Diffraction, Scanning Electron Microscopy,  Gas Chromatography, Microporousity measurement, and slow pyrolysis at the University of Hull.

Outcomes and Benefits

The main outputs from the project include:

  • Development and demonstration of the biochar production process from Subcoal biomass.
  • Design a novel carbon adsorbent material for CO2 capture.
  • Engagement with industry, academia, and the public to generate new carbon capture projects using functionalised biochars.
  • Dissemination of the overall research in the form of peer-reviewed publications and progress throughout will be presented in the relevant conferences and workshops.
  • The student will acquire extensive technical knowledge suitable for pursuing an academic path or working in various roles in the industry.

The project’s outcomes will benefit the academic and industrial sectors in the UK. For academia, it is a step in a long journey of efforts and achievements for sustainable and efficient technologies for CCS. The findings of this project will contribute to the UK’s Net Zero-2050 target by cutting greenhouse gas emissions by 100%. Utilising non-recyclable waste reduces the load on the UK’s landfills, which experience an increasingly shortening capacity gap. Regarding the economic impacts, this project contributes to the principles and goals of the circular economy by utilising waste materials, minimising the biomass sent to landfills, and reducing carbon footprints.

University of Hull webinar

The University of Hull is running a free webinar on Tuesday, 28 November, at 5 pm, giving you the opportunity to meet their PhD supervisors and current students from the Panorama Doctoral Training Partnership. Find out more about Hull-based research projects and ask your own questions about the programme. Click here to book your place.

How to apply

Please follow panorama-dtp.ac.uk/how-to-apply/; and send your CV to a.z.al-gailani@hull.ac.uk 

Key References

  1. Mishra, R. K., & Mohanty, K. (2023). A review of the next-generation biochar production from waste biomass for material applications. Science of the total environment, 904, 167171. doi:https://doi.org/10.1016/j.scitotenv.2023.167171
  2. Guo, S., Li, Y., Wang, Y., Wang, L., Sun, Y., & Liu, L. (2022). Recent advances in biochar-based adsorbents for CO2 capture. Carbon Capture Science & Technology, 4, 100059. doi:https://doi.org/10.1016/j.ccst.2022.100059