【摘要】 为探究H₂O₂改性和NaBH₄改性稻壳生物炭（BC-H₂O₂和BC-NaBH₄）对反硝化过程和N₂O排放的影响及机理,在制备并测定BC-H₂O₂和BC-NaBH₄理化性质及其表面含氧官能团含量基础上,将未改性生物炭（BC）、BC-H₂O₂和BC-NaBH₄以1%（w/V）的比例分别加入含有厌氧反硝化细菌（DB）的培养体系,开展DB去除模拟废水中低浓度硝酸盐（约10mg/L,以N计）的室内培养实验.结果表明,H₂O₂改性增加了生物炭表面的羧基含量,而NaBH₄改性增加了生物炭表面的内酯基和酚羟基含量.另外,傅立叶变换红外光谱分析表明,与BC相比,BC-H₂O₂的C=O含量明显增加.DB+BC-H₂O₂和DB+BC-NaBH₄处理的反硝化速率峰值较DB+BC处理提前12h出现,且分别高17.50%和6.32%.与DB+BC处理相比,DB+BC-NaBH₄处理的N2O累积排放量增加10.43%,但差异不显著; DB+BC-H₂O₂处理的N₂O累积排放量显著增加165.54%, N₂O/（N2O+N2）比值显著增加170.00%,但N₂O+N₂累积排放量之间无显著差异（P<0.05）,表明BC-H₂O₂抑制反硝化过程中N₂O向N₂还原,进而促进N₂O排放,这可能与添加BC-H₂O₂使培养体系的pH值、碳生物有效性降低以及C=O含量增加有关.更多还原

【Abstract】 The study focused on exploring the effects of H₂O₂-and NaBH₄-modified rice husk-derived biochars（BC-H₂O₂ and BC-NaBH₄） on denitrification and N₂O emission and the potential mechanisms. Based on BC-H₂O₂ and BC-NaBH₄ preparation and their physicochemical property and surface oxygen-containing functional group content determination, the pristine rice husk-derived biochar（BC）, BC-H₂O₂, and BC-NaBH₄ were added into the incubation system containing the screened anaerobic denitrifier（DB） at the ratio of 1%（w/V）, respectively. The microcosm incubation experiment was carried out to explore the removal efficiency of nitrate nitrogen（about 10mg/L） from simulated wastewater by DB. Results showed that H₂O₂-modification increased the carboxyl content on the surface of biochar, while Na BH₄-modification increased the contents of lactone and phenolic hydroxyl on the surface of biochar. In addition, the Fourier transform infrared spectra analysis showed that C=O content of BC-H₂O₂ was significantly higher than that of BC. The denitrification rate peaks of DB+BC-H₂O₂ and DB+BC-NaBH₄ appeared 12h earlier and their values were 17.50% and 6.32% higher than that of DB+BC, respectively. Compared with DB+BC, the cumulative N₂O emission of DB+BC-NaBH₄ increased by 10.43%, but the difference was not significant. However, the cumulative N₂O emission of DB+BC-H₂O₂ increased by 165.54% and the N₂O/（N₂O+N₂） ratio increased by 170.00% significantly, while there was no significant difference in the cumulative N₂O+N₂ emission between DB+BC-H₂O₂ and DB+BC（P<0.05）. The result indicated that BC-H₂O₂inhibited N₂O reduction to N₂ and promoted N₂O emission, which might be related to the decrease of pH and carbon bioavailability and the increase of C=O content induced by BC-H₂O₂ amendment.更多还原