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Advanced Carbon Materials from Biowaste: Sustainable Pathways to Drive Innovative Green Technologies

Periodic Reporting for period 1 - GreenCarbon (Advanced Carbon Materials from Biowaste: Sustainable Pathways to Drive Innovative Green Technologies)

Reporting period: 2016-10-01 to 2018-09-30

The energy crisis, environmental pollution and global warming are serious problems that are of great concern throughout the world. World´s current energy consumption is estimated to 500 EJ/year out of which around 40% is dedicated to the production of materials and chemicals. Materials as today are mostly derived from fossil fuels and so is the global energy. These materials need to be simple to synthesise, as cost effective as possible and ideally based on renewable resources as we are running out of certain key elements such as Pt, Ir, Ru, Rh, etc. These high-performance materials should have specific characteristics and be designed for performing specific functions in the fields of energy and environment.
Carbon materials are ideal candidates for performing many of these functions. Carbon can be found in a wide variety of allotropes, from crystalline (diamond and graphite) to amorphous (carbon black, activated carbon, etc.). In the past decade, the nanostructured forms of crystalline carbon (fullerenes, carbon nanotubes and graphene) have received the most attention due to remarkable and unusual physicochemical properties. However, the main disadvantage of using these crystalline nanocarbons for energy and environmental related application is their high production costs. Alternatively, carbon materials derived from renewable resources (e.g. lignocellulosic biomass) will play a very powerful role in this direction in the near future. So far, excluding activated carbons, relatively little research has been conducted on the synthesis and characterisation of carbon materials based on natural resources.
The objectives of the research programme are: (i) developing engineered thermochemical processes (based on pyrolysis and hydrothermal carbonisation from dry and wet biomass sources, respectively) to produce tailor-made biomass-derived carbons (BCs); (ii) developing novel low-cost carbon materials from BCs through a unique set of functionalisation protocols; (iii) using the resulting carbon materials in advanced applications in heterogeneous catalysis for renewable energy (e.g. pyrolysis vapours upgrading) as well as pollutants removal (e.g. CO2 capture in post-combustion and desulphurisation of biogas); and (iv) analysing the feasibility of using BCs as soil enhancers and carbon sequestration agents.
The main objective of our proposed Innovative Training Network is to develop new scientific knowledge, capability, technology, and commercial products for biomass-derived carbons; thus impacting the way that Europe uses and innovates with sustainable carbon materials. This will be accomplished through a rigorous training programme for fourteen early-stage researchers (ESRs) enhancing the European knowledge economy and closing loops on agricultural waste utilisation while creating new bridges between various sectors (e.g. agriculture-chemical and materials industries). GreenCarbon will train a new generation of scientists capable of not only scientific rigour, but also entrepreneurship allowing for itinerant deployment of themselves and their knowledge into the real world.
The research programme of GreenCarbon consists of four strongly interconnected work packages (WPs 4-7). The work carried out during the reporting period to within each WP is summarised below.

WP 4: Pyrolysis Conversion Routes for Dry Feedstocks. The first task within this WP was to decide the feedstocks to work with. It was agreed to work with 3 to 4 feedstocks at each node. Of these selected feedstocks, 2 would be common and shared among all nodes within WP 4 (wheat straw and wood waste). With the aim to set the most appropriate slow pyrolysis process conditions, several experimental studies have already been conducted. Regarding the continuous intermediate pyrolysis and fast pyrolysis, preliminary studies were also done in order to establish the most appropriate characteristics of such systems at laboratory scale. Finally, during this reporting period, a comprehensive pyrolysis/carbonisation model has already been developed.

WP 5: HTC Conversion Routes for Wet Feedstocks. The objective of this task is the assessment of the potential of different wet biomass sources (including lignin from bio-refinery processes) to produce engineered hydrochars or pyrochars through an HTC process or a cascaded HTC-fast pyrolysis process, respectively. A high number of experiments was already conducted at UHOH and FHG at both laboratory and pilot-plant scale in order to set the most appropriate operating conditions in terms of energy efficiency as well as the properties of the produced chars.

WP 6: Refining of BCs and Advanced Applications. This WP is designed for the functionalisation and modification of the biomass-derived carbons (BCs) produced within the previous WPs. Activated carbons (ACs) from corresponding BCs are being developed for both CO2 capture and biogas desulphurisation purposes through several synthesis methods (based on hydrothermal treatment and/or chemical vapour deposition). Several pyrochars have been physically and chemically activated to be used as low-cost and sustainable catalysts for cracking and reforming of pyrolysis vapours. Activated biochars having an appropriate pore size distribution have been assessed as appropriate materials for pyrolysis vapours upgrading. In the next months, Ni- and Fe-based catalysts supported onto activated carbons will be synthetised to evaluate their performance in catalytic upgrading in terms of temperature required, conversion, and selectivity towards H2. Magnetic catalysts are being prepared by hydrothermal treatments. The resulted materials will be used for the production of 5-HMF (and/or other chemical platforms) via hydrothermal processing of wet biomass.

WP 7: Sequential Biochar Systems. The objective of this WP is to integrate expertise across the GreenCarbon network, focusing on identifying synergistic sequences for BC uses, spanning engineering, agricultural and horticultural applications, in order to maximise the added-value and minimise carbon footprint across the whole chain. Several experimental studies are being conducted to assess: (a) the effect of biomass feedstock and pyrolysis conditions on the carbon sequestration potential of BCs, and (b) the effect of replacing peat by BCs as growing media.
The originality of GreenCarbon is the proposed multidisciplinary approach involving studies on all the essential parts needed to develop greener materials from sustainable resources. To the best of our knowledge there is no other consortium worldwide looking synergistically at all these aspects related to biomass-derived carbons (BCs). Our research programme comprehensively covers all aspects from precursors (the nature of biomass) to processing (thermochemical conversion, porosity development, chemical functionalisation) and application (CO2 capture, heterogeneous catalysis, and chemicals from biomass) enabling a unique design of engineered sustainable BC materials. In terms of expected results, the proposed methods and the continuous feedback across the different working packages will provide groundbreaking results concerning the most efficient way to produce BCs for given applications.