不同电荷聚苯乙烯纳米塑料对污水生物脱氮性能影响  

Effect of Differentially Charged Polystyrene Nanoplastics on the Performance of Biological Denitrification in Wastewater Treatment

作　　者：李晓华 段建鲁 祝凡平 袁宪正 LI Xiao-hua;DUAN Jian-lu;ZHU Fan-ping;YUAN Xian-zheng(Shandong Key Laboratory of Water Pollution Control and Resource Reuse,School of Environmental Science and Engineering,Shandong University,Qingdao 266237,China)

机构地区：[1]山东大学环境科学与工程学院,山东省水污染控制与资源再利用重点实验室,青岛266237

出　　处：《环境科学》2024年第12期7286-7294,共9页Environmental Science

基　　金：国家自然科学基金项目(21776163);国家资助博士后研究人员计划项目(GZC20231445);中国博士后科学基金项目(2023M732058)。

摘　　要：纳米塑料广泛分布于环境中并可在生物体内积累,其对污水生物处理过程的负面作用受到人们的广泛关注.研究合成了不同电荷的聚苯乙烯纳米塑料,并在序批式活性污泥反应器中分析了短期暴露对生物脱氮性能的影响.结果表明,带正电荷和负电荷的纳米塑料均抑制活性污泥的脱氮效率以及硝化和反硝化相关基因的表达,进而不同程度地抑制了硝化和反硝化过程,且这种抑制作用随浓度的增加而增强.研究利用模式反硝化细菌Pseudomonas stutzeri(P.stutzeri)进一步评价了不同电荷纳米塑料影响反硝化效率的分子机制.结果表明带正电荷和负电荷的纳米塑料均影响了P.stutzeri生物反硝化的效率,主要包括促进NO_(3)^(-)向NO_(2)-的转化和显著加速N_(2)O的产生.同时,负电荷纳米塑料会抑制P.stutzeri的生长,破坏菌体细胞膜,但反硝化相关功能基因表达情况并无变化,纳米塑料可能影响了Nir和Nos的酶活性,从而影响生物处理效率.研究结果可为纳米塑料的生物安全性评价提供一定的参考,为污水处理厂的稳定运行提供一定的支持.Nanoplastics are widely distributed in the environment and can accumulate in organisms.Increasing attention has been paid to the toxic effects of nanoplastics in wastewater biological treatment processes.In this study,polystyrene nanoplastics with different charges were synthesized and used in sequencing batch activated sludge reactors for short-term nanoplastic exposure experiments.Both positively and negatively charged nanoplastics inhibited the nitrogen removal efficiency and gene expressions of nitrification and denitrificationrelated genes of activated sludge.The inhibiting effect on nitrification of both nanoplastics was enhanced with increasing concentration.The study further evaluated the molecular mechanisms by which differently charged nanoplastics affect denitrification efficiency using the model denitrifying bacterium Pseudomonas stutzeri(P.stutzeri).The results showed that both positively and negatively charged nanoplastics affected the efficiency of biological denitrification by P.stutzeri,mainly including the promotion of NO_(3)^(-)to NO_(2)-conversion and the significant acceleration of N_(2)O production.Meanwhile,negatively charged nanoplastics inhibited the growth of P.stutzeri and disrupted the cell membrane of the bacterium;however,no change was observed in the expression of denitrification-related functional genes and the nanoplastics might have affected the enzymatic activities of Nir and Nos,which in turn affected the bioprocessing efficiency.This study can provide a certain reference for the evaluation of the biosafety of nanoplastics and provide a certain support for the stable operation of wastewater treatment plants.

关 键 词：纳米塑料(NPs) 表面电荷 废水处理 氮去除 施氏假单胞菌(Pseudomonas stutzeri) 

分 类 号：X703[环境科学与工程—环境工程]