• 关键词：生物钯纳米粒子（Bio-PdNPs）  反硝化  氮气选择性  电子传递

• 基金项目：国家自然科学基金（No.22276061，41977316）

• 毕耜静
• 华南理工大学环境与能源学院，工业聚集区污染控制与生态修复教育部重点实验室，广州 510006

• 陈元彩
• 华南理工大学环境与能源学院，工业聚集区污染控制与生态修复教育部重点实验室，广州 510006

• 胡勇有
• 华南理工大学环境与能源学院，工业聚集区污染控制与生态修复教育部重点实验室，广州 510006

• 摘要：为强化生物反硝化选择性脱氮，利用普通的反硝化污泥合成生物钯纳米粒子（Bio-PdNPs），探究了不同Bio-PdNPs负载量（0、5、10 mg·L^-1，分别记为Bio-PdNPs-0、Bio-PdNPs-5和Bio-PdNPs-10）对生物反硝化的影响.结果表明，适量钯的负载（Bio-PdNPs-5）可使硝酸盐去除率由67.85%提高到94.00%（C/N=7，5 h），对氮气的选择性由77.30%提高到97.46%.而负载过量的钯（Bio-PdNPs-10）会抑制生物反硝化，但其对N₂的选择性仍然高达90.01%，这对减少温室气体N₂O的排放具有重要意义.机理分析表明，Bio-PdNPs介导的反硝化体系以丁酸型发酵和混合性发酵为主，产生的氢气通过在钯表面迅速分解形成Pd［H］催化反硝化，提高对N₂的选择性，Bio-PdNPs促进了反硝化过程电子传递及电子传递介质（细胞色素c）的分泌，电子传递体系活性（ETSA）由570.37 μg·mg^-1·h^-1提高到647.22 μg·mg^-1·h^-1.

• Abstract：In order to improve the nitrogen selectivity （Ns） of bio-denitrification， in this study， palladium nanoparticles （Bio-PdNPs） were biosynthesized by the denitrifying sludge， and the effects of different Bio-PdNPs loading （0， 5 and 10 mg·L^-1） were investigated. The results showed that the nitrate removal efficiency increased from 67.85% to 94.00%（C/N=7， 5 h） at appropriate palladium loading （Bio-PdNPs-5）， and the corresponding Ns increased from 77.30% to 97.46%. However， excessive Pd loading （Bio-PdNPs-10） inhibited denitrification， but the Ns was still up to 90.01%， which is of great significance for reducing N₂O emissions. The mechanism analysis showed that Bio-PdNPs mediated denitrification was mainly attributed to butyric acid type and mixture fermentation， in which the hydrogen produced by fermentation could be rapidly captured by PdNPs and decomposed to form Pd［H］， eventually improved Ns. In addition， Bio-PdNPs also promoted electron transfer via stimulating the secreting cytochrome c， resulting in the electron transport system activity （ETSA） increasing from 570.37 μg·mg^-1·h^-1to 647.2 2 μg·mg^-1·h^-1.

• Key words：biosynthetic nano-palladium（Bio-PdNPs）  denitrification  nitrogen selectivity  electron transfer

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