On the Design of Novel Biofoams Using Lignin, Wheat Straw, and Sugar Beet Pulp as Precursor Material

Sweet Side Streams: Sugar Beet Pulp as Source for High-Performance Supercapacitor Electrodes

Valorization of the lignocellulosic side and waste streams is key to making industrial processes more efficient from both an economic and ecological perspective. Currently, the production of sugars from beets results in pulps in large quantities. However, there is a lack of promising opportunities for upcycling these materials despite their promising properties. Here, we investigate beet pulps from two different stages of the sugar manufacturing process as raw materials for supercapacitor electrodes. We demonstrate that these materials can be efficiently converted to activated, highly porous carbons. The carbons exhibit pore dimensions approaching the size of the desolvated K+ and SO42- ions with surface areas up to 2600 m2 g-1. These carbons were subsequently manufactured into electrodes, assembled in supercapacitors, and tested with environmentally friendly aqueous electrolytes (6 M KOH and 1 M H2SO4). Further analysis demonstrated the presence of capacitance-enhancing functionalities, and up to 193 and 177 F g-1 in H2SO4 and KOH, respectively, were achieved, which outperformed supercapacitors prepared from commercial YP80 F. Overall, our study suggests that side streams from sugar manufacturing offer a hidden potential for use in high-performance energy storage devices.

Experimental Design Optimization of Acrylate-Tannin Photocurable Resins for 3D Printing of Bio-Based Porous Carbon Architectures

In this work, porous carbons were prepared by 3D printing formulations based on acrylate-tannin resins. As the properties of these carbons are highly dependent on the composition of the precursor, it is essential to understand this effect to optimise them for a given application. Thus, experimental design was applied, for the first time, to carbon 3D printing. Using a rationalised number of experiments suggested by a Scheffé mixture design, the experimental responses (the carbon yield, compressive strength, and Young's modulus) were modelled and predicted as a function of the relative proportions of the three main resin ingredients (HDDA, PETA, and CN154CG). The results revealed that formulations containing a low proportion of HDDA and moderate amounts of PETA and CN154CG gave the best properties. Thereby, the optimised carbon structures had a compressive strength of over 5.2 MPa and a Young's modulus of about 215 MPa. The reliability of the model was successfully validated through optimisation tests, proving the value of experimental design in developing customisable tannin-based porous carbons manufactured by stereolithography.

Batch Pyrolysis and Co-Pyrolysis of Beet Pulp and Wheat Straw

Granulated beet pulp and wheat straw, first separately and then mixed in a weight ratio of 50/50%, underwent a pyrolysis process in a laboratory batch generator with process temperatures of 400 and 500 °C. The feedstock’s chemical composition and the pyrolysis products’ chemical composition (biochar and pyrolysis gas) were analysed. A synergistic effect was observed in the co-pyrolysis of the combined feedstock, which occurred as an increase the content of the arising gas in relation to the total weight of the products. and as a reduction of bio-oil content. The maximum gas proportion was 21.8% at 500 °C and the minimum between 12.6% and 18.4% for the pyrolysis of individual substrates at 400 °C. The proportions of the gases, including CO, CO₂, CH₄, H₂, and O₂, present in the resulting synthesis gases were also analysed. The usage of a higher pyrolysis final temperature strongly affected the increase of the CH₄ and H₂ concentration and the decrease of CO₂ and CO concentration in the pyrolysis gas. The highest percentage of hydrogen in the synthesis gas, around 33%_vol, occurred at 500 °C during co-pyrolysis.

Revisiting lignin: a tour through its structural features, characterization methods and applications

A pedagogical overview of the main extraction procedures and structural features, characterization methods and state-of-the-art applications.