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采用不同液相还原法制备纳米Fe0、Fe/Ni和Fe/Cu粒子,将其与反硝化细菌混合应用于地下水NO3--N去除研究。考察3种体系对NO3--N去除速率的影响,并对其脱氮产物及RNA水平上纳米铁系双金属对反硝化细菌的毒性效应进行了分析和讨论。结果表明,9 d内纳米Fe0体系可完全将NO3--N去除,过程中伴随NO2--N先升高后降低的生成趋势,NH 4+-N生成52%;纳米Fe/Ni体系脱氮速率最快,6 d内可将NO 3--N完全去除,几乎未检测到NO 2--N的生成,而NH 4+-N的转化率高达69%;纳米Fe/Cu体系7 d内可将NO3--N去除完全,NH4+-N的生成率降低,仅39%,但是出现33%NO2--N积累。从反应前后反硝化细菌总RNA浓度变化看,3种纳米粒子对反硝化细菌的毒性大小为纳米Fe/Ni﹥纳米Fe/Cu﹥纳米Fe0。
Nano - Fe0, Fe / Ni and Fe / Cu particles were prepared by different liquid reduction methods and mixed with denitrifying bacteria to remove NO3 - N from groundwater. The effects of three systems on NO3 - N removal rate were investigated. The toxicological effects of denitrification products and nano-iron-based bimetallics on denitrifying bacteria were analyzed and discussed. The results showed that NO3 - N could be completely removed by Nano - Fe0 system within 9 days, with NO2 - N increasing first and then decreasing with the formation of NH4 + -N. The N0 + The fastest rate of NO 3 - N removal was achieved within 6 days, with almost no NO 2 - N generation and no NH 4 + -N conversion up to 69%. The nano Fe / Cu system within 7 days NO3 - N can be completely removed, NH4 + -N production rate decreased by only 39%, but 33% NO2 - N accumulation occurred. From the changes of the total RNA concentration of the denitrifying bacteria before and after the reaction, the toxicities of the three kinds of nanoparticles to the denitrifying bacteria are nano-Fe / Ni> nano-Fe / Cu> nano-Fe0.