Straw Biochar-Facilitated Methanogenesis from Acetic Acid and Ethanol: Correlation with Electron Exchange Capacity

Straw biochar prepared by three methods (i.e., pyrochar, HNO3-modified and hydrochar) was added to the anaerobic digestion system with acetic acid ethanol as substrates explore effects of on methane production, substrate degradation, microbial community structure. The biogas yields biochar-supplemented groups all increased, maximum yield found in hydrochar group, which 45.4% higher than control. In ethanol-fed reactor, partial pressure hydrogen headspace reactor reduced from 3.5% (blank reactor) 1.9%. Overall, production is directly proportional electron exchange capacity (EEC) value biochar. Furthermore, bio-aging process increased EEC each kind 5.5–8.1%, favorable for sustainable promotion methanogenesis. bio-aged could either be attributable changes surface oxygen-containing functional or selectively enriched biochar, such Geobacter, participate direct interspecies transfer.