Self-generation of low ash carbon microspheres from the hydrothermal supernatant of anaerobic digestate: Formation insights and supercapacitor performance

Chemical Engineering Journal Advances

卷:6

João Figueira¹  Ivan Kozyatnyk²  Stina Jansson³  Markus Carlborg⁴  Kenneth G. Latham⁴  Erik Rosenbaum⁵ 

[1] Corresponding author at: Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden.;

[2] Discipline of Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia;

[3] Umeå University, Department of Applied Physics and Electronics, SE-901 87 Umeå, Sweden;

[4] Umeå University, Department of Chemistry, SE-901 87 Umeå, Sweden;

[5] Umeå University, Scilife Lab, Department of Chemistry, SE-901 87 Umeå, Sweden;

关键词: Sediment;    Solid state NMR;    Electrochemical capacitors;    Hydrochar;    Wet waste materials;   

DOI  :  

来源: DOAJ

【 摘 要 】

This work provides the first observations of and insights into the self-generation of carbon microspheres from the supernatant after hydrothermal carbonization of anaerobic digestate has been completed and the hydrochar removed. Solid State NMR and XPS revealed that the carbon microspheres were comprised of decomposed fragments of proteins, carbohydrates and lignin. The carbon microspheres were significantly lower in ash content (3.1%), compared to the hydrothermal solid (41.2%) and precursor (25.2%) and their formation reduced the total organic carbon load of the supernatant. The low ash content allowed them to be easily activated, achieving a surface area of 1711.0 m2 g−1, compared to 51.4 m2 g−1 for the activated hydrothermal solid and 12.8 m2 g−1 for the activated precursor. The microcarbon spheres achieved a specific capacitance from cyclic voltammetry of 86 F g−1 at 100 mV s−1 to 176 F g−1 at 1 mV s−1, while the gravimetric capacitance was 42 F g−1 at 25 A g−1 and 140 F g−1 at 0.5 A g−1 in 0.5 M Li2SO4 and a 1.8V potential window. Overall, this study highlights the importance of exploring this new product and its valorisation potential for the hydrothermal carbonization of ash-rich precursors.

【 授权许可】

Unknown