Fakultät Agrarwissenschaften

Permanent URI for this communityhttps://hohpublica.uni-hohenheim.de/handle/123456789/9

Die Fakultät entwickelt in Lehre und Forschung nachhaltige Produktionstechniken der Agrar- und Ernährungswirtschaft. Sie erarbeitet Beiträge für den ländlichen Raum und zum Verbraucher-, Tier- und Umweltschutz.

Homepage: https://agrar.uni-hohenheim.de/

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Crucial interactions of functional pyrenes with graphite in electrodes for lithium‐ion batteries
(2023) Bauer, Marina; Konnerth, Philipp; Radinger, Hannes; Pfeifer, Kristina; Joshi, Yug; Bauer, Felix; Ehrenberg, Helmut; Scheiba, Frieder
Polycyclic aromatic hydrocarbons, such as pyrenes, are a well‐known material class for non‐covalent modification of carbon surfaces in many applications. In electrochemical energy storage, pyrenes are mostly used in large polymeric structures. This work addresses the use of carboxy‐ and amino‐functionalized pyrenes for graphite electrodes for lithium‐ion batteries (LIBs). Pyrenes are explored as adsorbed species on graphite prior to electrode fabrication and as additives to the electrode composition. Thereby, 1‐pyrenecarboxylic acid, 1‐pyrenebutyric acid, 1‐aminopyrene, and 1‐pyrenebutylamine were under investigation. As additives, pyrenes do not influence the cycling performance of the electrode at low current but deteriorate the performance at high current, regardless of the functional group. However, when the pyrenes are adsorbed to the graphite surface, the influence of the different functional groups becomes clearly visible, revealing that an additional butyl group has a positive impact on the cycling performance and lithium‐ion transport of the electrodes. Electrodes with 1‐pyrenebutyric acid even enhanced the performance compared to the pristine electrode.
Impact of thermo-mechanical pretreatment of sargassum muticum on anaerobic co-digestion with wheat straw
(2023) Hütter, Miriam; Sailer, Gregor; Hülsemann, Benedikt; Müller, Joachim; Poetsch, Jens
Sargassum muticum (SM) is an invasive macroalgal species seasonally occurring in large quantities. While generally suitable for anaerobic digestion, recent studies resulted in low specific methane yields (SMYs), presumably due to salt, polyphenol, and high fiber contents of this marine biomass. In this study, the specific biogas yield (SBY) and SMY of SM alone as well as in co-digestion with wheat straw (WS) were investigated in batch tests at process temperatures of 44 ± 1.4 °C with a retention time of approx. 40 d. The pretreatment variants of SM were examined with regard to desalination and disintegration to potentially improve digestibility and to enhance the overall performance in anaerobic digestion. A sole mechanical treatment (pressing) and a thermo-mechanical treatment (heating and pressing) were tested. Batch assays showed that pressing increased the SMY by 15.1% whereas heating and pressing decreased the SMY by 15.7% compared to the untreated variant (87.64 ± 8.72 mL/gVS). Both anaerobic digestion experiments generally showed that co-digestion with WS can be recommended for SM, but the observed SBY and SMY were still similar to those of other studies in which SM was not pretreated. The mechanical pretreatment of SM, however, offers the potential to enhance the SMY in the anaerobic digestion of SM with WS, but further research is necessary to identify the optimum upgrading approaches since the overall SMY of SM is relatively low compared to other substrates that are commonly used in anaerobic digestion. In addition to anaerobic digestion, SM as an already available biomass could also be of interest for further utilization approaches such as fiber production.
Lab-scale carbonation of wood ash for CO2-sequestration
(2021) Koch, Robin; Sailer, Gregor; Paczkowski, Sebastian; Pelz, Stefan; Poetsch, Jens; Müller, Joachim
This study evaluated the CO2 sequestration potential with combustion ashes in the aqueous phase. The aim was to provide a cost-effective carbon sequestration method for combustion unit operators (flue gas cleaning) or biogas producers (biogas upgrading). Therefore, two separate test series were executed to identify the carbonation efficiency (CE) of bottom wood ash (1) at different mixing ratios with water in batch experiments and (2) under dynamic flow conditions. It was furthermore evaluated whether subsequent use of the carbonated wood ash for soil amendment could be possible and whether the process water could be passed into the sewage. The batch test series showed that different mixing ratios of wood ash and water had an influence on the CE. The flow series showed that the mean CE varied between approximately 14% and 17%. Thus, the ash proved to be suitable for carbonation processes. The process water was dischargeable, and the carbonated wood ash has potential for chalking, as no legal thresholds were exceeded. Therefore, wood ash carbonation could be used as a low-tech CO2 sequestration technology. Compared to existing energy consuming and cost intensive carbon capture and storage technologies, sequestration with ash could be beneficial, as it represents a low-tech approach.

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