Biomass Combustion Fly Ash-Derived Nanoporous Zeolites for Post-Combustion Carbon Capture

Abstract

Achieving negative CO2 emissions via the combustion of sustainable biomass - known as bioenergy with carbon capture and storage - is inherently linked to the co-production of a significant amount of potentially hazardous waste combustion fly ash. Valorisation of this solid waste stream presents obvious economic, social, and environmental incentives within the context of waste utilisation and environmental protection. However, the origin of the biomass (the regional plantation) used during the combustion, dictates the physicochemical properties of this solid residue, making it suitable for specific applications while rendering it less favourable for others. In this study, a nanoporous zeolite as a CO2 adsorbent has been synthesised from industrial-grade biomass combustion fly ash generated in one of the largest biomass combustion power plants in the UK. The method of nanoporous zeolite synthesis follows a fusion-assisted hydrothermal procedure and the produced nanoporous zeolite has been characterised by X-ray diffraction. The CO2 adsorption investigations were conducted via thermogravimetric analysis to estimate the uptake capacity of the prepared adsorbents. TGA studies suggest that the nanoporous adsorbent, run under 100 mol% CO2 at atmospheric pressure, has an equilibrium capacity of over 0.8 mmolCO2/g at 50°C. The characterisation results are in good agreement with our CO2 adsorption data, demonstrating the nanoporous structure of our synthesised waste-derived zeolites.