The addition of conductive materials or metal oxide nanoparticles (NPs) to anaerobic systems is an attractive strategy to enhance the anaerobic metabolism and the production of CH₄. This study proposed a strategy to boost the production of CH₄ by adding granular activated carbon (GAC)-MnO₂ nanocomposites into an anaerobic methanogenic system. The associated mechanisms and the microbial community structure during anaerobic digestion were investigated systematically. Compared with a control with GAC only, after adding GAC-MnO₂ composite the chemical oxygen demand (COD) removal efficiency and CH₄ yield were increased by 77% and 36%, respectively. The addition of GAC-MnO₂ stimulated the secretion of extracellular polymeric substance (EPS), while the secretion of humic substances was inhibited. The spatial distribution of EPS in the anaerobic sludge affects the extracellular electron transfer efficiency as well. Manganese ions concentrated in the EPS layer facilitated the electron flow and, thus, accelerated the extracellular electron transfer. The enhancement of anaerobic methanogenesis can be mainly attributed to the reduction/oxidation cycle of Mn⁴⁺/Mn²⁺. Electron transfer system activity and Cytochrome C content reached up to 341 and 38 nmol/L, respectivety, under optimal conditions. 16S rRNA gene sequencing analysis indicated that Spirochaetaceae, Cloacibacterium, and Treponema were the dominant bacteria. The abundance of the methanogenic archaea Methanobacterium and Methanosaeta was increased with the addition of GAC-MnO₂.

向厌氧系统添加导电材料或金属氧化物纳米颗粒（NPs）是提高厌氧代谢和CH ₄产生的有吸引力的策略。这项研究提出了一种通过向厌氧产甲烷系统中添加颗粒状活性炭（GAC）-MnO ₂纳米复合材料来提高CH ₄产量的策略。系统地研究了厌氧消化过程中的相关机制和微生物群落结构。与仅使用GAC的对照相比，添加GAC-MnO ₂复合物后，化学需氧量（COD）去除效率和CH ₄产率分别提高了77％和36％。GAC-MnO _2的添加刺激了细胞外聚合物质（EPS）的分泌，而抑制了腐殖质的分泌。厌氧污泥中EPS的空间分布也影响细胞外电子转移效率。浓缩在EPS层中的锰离子促进了电子流动，从而加速了细胞外电子的转移。厌氧甲烷生成的增强主要归因于Mn ⁴⁺ / Mn ²⁺的还原/氧化循环。在最佳条件下，电子转移系统的活性和细胞色素C的含量分别达到341和38 nmol / L。16S rRNA基因序列分析表明，螺旋藻科，梭菌和螺旋体是占主导地位的细菌。在产甲烷古菌的大量甲烷和Methanosaeta通过加入GAC-的MnO增加₂。