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作者： Jie Yea, Andong Hua, Guoping Rena, Man Chena, Jiahuan Tanga, Panyue Zhangb, Shungui Zhoua, Zhen Hec
a Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
b Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
c Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
摘要：Different conductive materials have been employed to stimulate direct interspecies electron transfer (DIET) during methanogenesis, but few studies have been concerned with the interaction between conductive materials and extracellular polymeric substances (EPS) such as the effect on sludge aggregation and redox activity of EPS. This study aims to systematically investigate the role of red mud with 45.46?wt% hematite on methanogenesis during the anaerobic digestion of waste activated sludge. The results showed that the multivalent cations from hematite effectively promoted the formation of large and compact aggregates, which might contribute to the rapid direct electron exchange during the DIET process. Meanwhile, more redox-active mediators including c-type cytochromes (c-Cyts) and humic substances, particularly in tight-bound EPS (TB-EPS), and more redox-active metals such as Fe introduced by red mud could take part in the interspecies electron transfer process between syntrophic bacteria and methanogenic archaea, which also promoted methane production (35.52?±?2.64% increase compared with the control). This study provided initial scientific evidence to comprehensively assess the role of conductive materials during methanogenesis, with important implications for the biogeochemical redox processes of conductive minerals in natural and engineered environments.
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