The effect of oxidative treatment on soluble compounds from Australian coal. (1st December 2019)

• Record Type: Journal Article
• Authors: Webster, John; Lee, Matthew; Gurba, Lila W.; Manefield, Michael; Thomas, Torsten
• Is Part Of: Fuel. Volume 257(2019)
• Publication Date: 2019-12-01
• Subjects: Coal degradation -- Metabolites -- Biogenic methane; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2019.116071
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract: The production of biogenic methane from coal has been observed through isotope analysis of coal bed methane (CBM). Microbial degradation of coal leads to the production of chemical compounds, which, under anaerobic conditions, can be biologically converted into methane. However, the types of coal compounds accessible to these microbial processes are poorly defined. This study aims to define the nature of chemical compounds released from coal under oxidative conditions. Coal from three different coal seams were extracted and released compounds were analysed with GC–MS and H-NMR. Coals were then exposed to hydrogen peroxide, calcium peroxide and peroxidase, which mimic microbial oxidation. Our analysis showed that the three coals shared around half of their apolar, mobile compounds, including alkanes ranging from C11 to C27 and methylated variations thereof, as well as poly-aromatic hydrocarbons, such as methylated naphthalenes, phenanthrenes and fluorenes. Oxidative treatments of coal caused significant changes in chemical profiles compared to untreated coal. All treatments resulted in the production of propionate, an important substrate for syntrophic methanogenesis. However, there were also qualitative and quantitative differences in the polar compounds produced during enzymatic and peroxide treatments. These results show how different chemical and enzymatic processes that are relevant to microbial oxidation will produce distinct profiles in intermediate metabolites that will likely then determine the subsequent pathways of microbial methane production.