木质纤维素基生物炭对葡萄糖厌氧消化性能的影响及机理研究

生物炭是提高厌氧消化性能的有效添加剂，由于生物炭性质的多样性和厌氧体系的复杂性，生物炭对厌氧消化的促进机理尚未得到全面认识。以生物质纯组分——纤维素、半纤维素和木质素为原料，分别采用水热法和热解法制备了生物炭，考察了生物炭对葡萄糖厌氧消化的影响，并从微生物分析、官能团组成和电导率等方面探究了其作用机理。结果表明：与对照组相比，生物炭的添加能加快葡萄糖厌氧消化速率，提高消化效率；相较于纤维素和半纤维素，以木质素为原料制备的生物炭的效果更好；以木质素为原料制备的水热炭和热解炭均能在一定程度上富集互养型发酵细菌，这可能有助于促进直接种间电子转移（DIET）机制的建立，从而提高产甲烷速率；生物炭丰富的表面含氧官能团和较大的电导率可能是其强化厌氧消化效果的关键特性；通过变异性分析发现，相较于制备方法，累积产甲烷量对生物炭原料的依赖性更大。

Effect of lignocellulosic biochar on the anaerobic digestion of glucose and its mechanism

The addition of biochar can improve anaerobic digestion performance. Due to the diversity of biochar properties and the complexity of anaerobic systems, the mechanism of the promotion of anaerobic digestion by biochar is not fully understood. Biochars were prepared by a hydrothermal method and a pyrolysis method with pure biomass components (cellulose, hemicellulose and lignin) as raw materials, and the effects of different biochars on anaerobic digestion of glucose were investigated. The mechanism was explored from the aspects of microbial analysis, functional group composition and electrical conductivity. The results showed that compared with the control group, the addition of biochar could accelerate the anaerobic digestion rate of glucose and improve digestion efficiency. Biochar prepared from lignin had a better effect than materials prepared from cellulose or hemicellulose precursors. The hydrothermal biochar and pyrolytic biochar prepared using a lignin precursor can enrich the heterotrophic fermentation bacteria to a certain extent, which may help promote the establishment of the direct interspecies electron transfer (DIET) mechanism and thus improve the methane production rate. The abundant surface oxygen-containing functional groups and large electrical conductivity of biochar may be the key properties responsible for its enhanced anaerobic digestion effect. By means of variability analysis, it was found that the cumulative methane production was more dependent on the biochar precursor than on the preparation method.