In this study, improved nanoporous zeolites for use in post-combustion carbon capture have 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 an alkaline fusion-assisted hydrothermal procedure. The nanoporous zeolites have been characterised by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The presence of two crystalline structures, Faujasite and Linde Type A has been confirmed by the characterisation results. The CO2 adsorption investigations were conducted via thermogravimetric analysis (TGA) to estimate the uptake capacity of the prepared adsorbents. TGA studies suggest that the improved nanoporous adsorbent, evaluated under 100 mol% CO2 at atmospheric pressure, has an equilibrium capacity of over 1.6 mmolCO2/g at 50 °C, a two-fold increase from our previous study with a crystalline structure confirmed by XRD.

Carbonaceous adsorbents are one of the most widely-used materials used for the removal of chemical species in gaseous and aqueous media. However, the route from precursor to activated carbon is riddled with myriad techniques and steps, that entail additional costs. Such expenses could be minimized via waste valorization e.g. biomass combustion bottom ash which has been used in this work. In order to develop surface nanoporosity, the waste-derived carbon was thermally treated, increasing the CO2 adsorption capacity by nearly twofold and thus, producing a cost-effective sorbent for postcombustion CO2 capture. The effectiveness of such "unconventional" activation route has been verified using Scanning Electron Microscopy, Fourier-Transform Infrared Spectroscopy as well as Proximate Analysis and the CO2 adsorption data obtained via Thermogravimetric Analysis (TGA). The proposed material and method could serve as a viable alternative to the current methods for decarbonization of the UK power sector through in-situ waste valorization.