Dr Roberto Volpe and his team at Queen Mary University of London and University College London have imaged the porosity of biochars for the first time, via unprecedented operando experiments at Diamond. Dr Volpe’s work to overcome existing knowledge gaps in the thermochemical decomposition of biomass could enable production of tailor-made bio-chars for high-priority environmental applications. With the support from a European Horizon 2020 grant called ExPaNDS - European Open Science Cloud (EOSC) Photon and Neutron Data Service - Diamond has worked with Dr Volpe on a new specific data-intensive technique used at the synchrotron to accelerate access to results.
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Dr Volpe’s current research involves examining and identifying the chars created from raw biomass of almond and walnut shells as their porosity is key to environmental applications. The ability to customise the morphology of these chars could herald a great breakthrough to help address global challenges by creating inexpensive and renewable solutions to energy storage, catalysis, water and soil remediation. Tracking the morphology of biomass during biochar production is the first step towards achieving this. He comments;
What we do is simple as we take almond and walnut shells and we put them through pyrolysis to create a char biomass – the study of carbonisation of biomass essentially reflects techniques dating back to the beginning of mankind by turning wood into charcoal. However, in our study, the process is monitored every step of the way and what we are interested in, is the porosity that is being created. By accurately heating, we can form up to more than a thousand square metres of accessible surface area in the intricate network of pores inside a single gram of formed biochars.
Dr Volpe continues;
Applications for this work are many as contaminants (bacteria, metals, polluting molecules) or ions (in the case of energy storage) can be carried by water (or by an electrolyte) into the intra-particle pore network, and they can be trapped there. Tracking the evolution of this pore network as we heat the biomass particles is key and the real novelty of this work.
In addition to traditional beamtime at Diamond, Dr Volpe has been working in collaboration on the data side of the ExPaNDS grant to develop new processes to accelerate access to data.
Dr Volpe says that the helping hand he received analysing his data from the ExPaNDS and Diamond team accelerated his research. Commenting he said that data mining of these huge datasets is a new discipline and requires extensive collaboration.
Sharing of such large and complex sets of information is challenging and the ExPaNDS grant helped identify better ways to deliver data management which is really useful to speed up results and transparency.
Dr Paul Quinn, Science Group Leader for Diamond's Imaging and Microscopy group explains:
Imaging techniques at Diamond allow the team to visualise the structure of the solid particle with enough detail to examine small gaps or pores and track any changes over time and with variations in temperature. This means that we can extract a great deal of detail about the evolution of these pores and their intricate geometry. This result sheds light on the fundamental behaviour of thermally treated biomass, and, at the same time, allows Dr Volpe and his team to uniquely correlate the particle and pores geometry to temperature.
This a great achievement made possible by the dedication of the scientists in my team. Dr Christoph Rau and the many others who have contributed to and supported the complex measurements, from advice on experiment feasibility, to experimental setup of the furnace to create the correct environment and optimal X-ray imaging conditions, to mining the wealth of data generated.
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As petabytes of data are produced in synchrotrons every year, the need for collaboration and a coordinated approach with these huge data sets is an issue facing most scientists /researchers especially those working in large scale facilities in the UK and Europe. To increase the value of this data, it needs to follow key principles ultimately be Findable, Accessible, Interoperable and Reusable (FAIR). These principles will help make data eventual open to all. A key goal of ExPaNDS is to make it easier to find and share research data which will help prevent repetition of experiments, spur scientific progress and make synchrotron data FAIR. A second goal of ExPaNDS is to provide guidelines on managing data to support sharing and reuse.
The ExPaNDS project is a collaboration between 10 national Photon and Neutron Research Infrastructures (PaN RIs). This community covers virtually all fields of research with a huge diversity in data management approaches. This makes harmonisation a challenge.
Professor Dr Helmut Dosch, Chairman of the Board of Directors for DESY, which is the leading partner in the ExPaNDS grant concludes:
We can now create solutions these days and in the future even more so - atom by atom, you know materials which can be used for fighting climate change and diseases. But this data, this information is coming with a huge avalanche of data to us, and we need concepts how to turn this data in to useful information and to knowledge. It needs the right people; it needs the right infrastructure, and it needs financial resources. But I only can say now that knowledge is expensive, but ignorance we cannot afford.”
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.
Beamline I13 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. 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 different chemical reactions occur in the confined space of evolving pores of biomass and how fast or how slow – the produced vapours are progressively released out of the particle though that evolving network of pores during pyrolysis. As such, as temperature is increased up to approximately 500 °C, pores develop more towards the surface, while beyond 500 °C, porosity starts to develop more towards the centre of particles. These heat and mass transport limitations are what make pyrolysis so challenging to resolve and control
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.
Dr Volpe explained that the carbonisation of biomass is a technique that dates back to the beginning of mankind by turning wood into charcoal. The full thermo-chemical aspects of this process is still largely unknown – however, his work to overcome existing knowledge gaps in the kinetics of pyrolysis and gasification of biomass could enable production of tailor-made bio-chars for high priority environmental applications. Dr Volpe’s current work involves examining and identifying the porosity and how it develops in chars he has created from raw biomass of almond and walnut shells. He says he and his team are the first to achieve this and they have the results but have not yet finished analysis mainly because of the enormous amount of data the work has generated. Understanding this porosity during thermo-chemical breakdown is key to unlocking significant technological development and the important applications for this work.
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