Tracking the shape of nutshells during biochar production

Authors: Meredith Rose Barr (Queen Mary University of London) , Roberto Volpe (Queen Mary University of London)
Co-authored by industrial partner: No

Type: Diamond Annual Review Highlight

State: Published (Approved)
Published: July 2021
Diamond Proposal Number(s): 21587

Abstract: A charcoal-like product known as ‘biochar’ can be produced from agricultural waste biomass such as nutshells. One conversion method is pyrolysis, a process that involves heating the waste in the absence of oxygen. During pyrolysis, changes in the size and shape (morphology) of particles increase the surface area of the biomass. This surface area controls how biochar binds to (adsorbs) pollutants, speeds up chemical reactions, and stores energy. A lack of understanding of how biomass morphology changes during biochar production makes it difficult to tailor biochar properties for specific applications. Facilities at the Diamond Manchester Imaging Branchline (I13-2) enabled a team of researchers to conduct rapid high-resolution X-ray imaging of biomass. This allowed real-time tracking of particle morphology and porosity during pyrolysis. The results showed that the morphology and porosity of different nutshells evolved differently during pyrolysis. However, these differences were less pronounced in biomass pre-soaked with an alkaline solution. Almond shells shrank more but gained less porosity than walnut shells, which have thicker- walled cells on average. The results suggest that the difference is related to how heat penetrates particles of biomass during pyrolysis. Porosity was found to accumulate towards the centre of particles during pyrolysis for the same reason. The ability to customise biochar morphology would benefit its many environmental applications. These include removing pollutants from air, water, and soil; speeding up chemical reactions; and even storing energy. Tracking the morphology of biomass during biochar production is the first step towards achieving this.

Journal Keywords: Biomass pyrolysis; Biochar; X-ray imaging; Morphology; Adsorption

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: I13-2-Diamond Manchester Imaging

Added On: 12/11/2021 14:08

Discipline Tags:

Biotechnology Chemistry Chemical Engineering Engineering & Technology

Technical Tags:

Microscopy X-ray Microscopy Topography