Long-term effects of titanium dioxide nanoparticles on nitrogen and phosphorus removal from wastewater and bacterial community shift in activated sludge.
Long-term effects of titanium dioxide nanoparticles on nitrogen and phosphorus removal from wastewater and bacterial community shift in activated sludge.
复制标题
DOI：
10.1021/es2008598
复制
发表时间：
2011-08
影响因子：
11.4
通讯作者：
Xiong Zheng;Yinguang Chen;Rui Wu
中科院分区：
文献类型：
--
作者：
Xiong Zheng;Yinguang Chen;Rui Wu
二氧化钛纳米颗粒（TiO(2) NPs）在广泛领域的广泛应用引起了人们对其潜在环境影响的关注。然而，关于TiO(2) NPs对活性污泥生物脱氮除磷和细菌群落的潜在影响的研究很少。在厌氧-低溶解氧（0.15 ~ 0.50 mg/L）序批式反应器中，研究了tio2 (2) NPs对生物去除营养物的影响。研究发现，1和50 mg/L的TiO(2) NPs短期暴露（1 d）后对废水氮磷去除无急性影响。然而，50 mg/L的TiO(2) NPs（高于其环境相关浓度）在长期暴露（70天）后显著降低总氮（TN）去除效率，从80.3%降至24.4%，而生物磷去除不受影响。变性梯度凝胶电泳图谱显示，50 mg/L的TiO(2) NPs显著降低了活性污泥中微生物群落的多样性，荧光原位杂交分析表明，长期暴露于50 mg/L的TiO(2) NPs后，硝化细菌，尤其是氨氧化细菌的丰度大幅下降，这是导致氨氧化严重恶化的主要原因。进一步研究发现，长期暴露50 mg/L的TiO(2) NPs可以抑制氨单加氧酶和亚硝酸盐氧化还原酶的活性，但对胞外多磷酸酶和多磷酸激酶的活性以及胞内多羟基烷酸酯和糖原的转化没有显著影响，这与TiO(2) NPs对生物脱氮除磷的影响一致。
The expanding use of titanium dioxide nanoparticles (TiO(2) NPs) in a wide range of fields raises concerns about their potential environmental impacts. However, investigations of the potential effects of TiO(2) NPs on biological nitrogen and phosphorus removal and bacterial community in activated sludge are sparse. This study evaluated the influences of TiO(2) NPs on biological nutrient removal in the anaerobic-low dissolved oxygen (0.15-0.50 mg/L) sequencing batch reactor. It was found that 1 and 50 mg/L TiO(2) NPs had no acute effects on wastewater nitrogen and phosphorus removal after short-term exposure (1 day). However, 50 mg/L TiO(2) NPs (higher than its environmentally relevant concentration) was observed to significantly decrease total nitrogen (TN) removal efficiency from 80.3% to 24.4% after long-term exposure (70 days), whereas biological phosphorus removal was unaffected. Denaturing gradient gel electrophoresis profiles showed that 50 mg/L TiO(2) NPs obviously reduced the diversity of microbial community in activated sludge, and fluorescence in situ hybridization analysis indicated that the abundance of nitrifying bacteria, especially ammonia-oxidizing bacteria, was highly decreased after long-term exposure to 50 mg/L TiO(2) NPs, which was the main reason for the serious deterioration of ammonia oxidation. Further study revealed that 50 mg/L TiO(2) NPs inhibited the activities of ammonia monooxygenase and nitrite oxidoreductase after long-term exposure, but had no significant impacts on the activities of exopolyphosphatase and polyphosphate kinase, and the transformations of intracellular polyhydroxyalkanoates and glycogen, which were consistent with the observed influences of TiO(2) NPs on biological nitrogen and phosphorus removal.