摘要
溶解性有机质(DOM)的存在会影响纳米氧化锌颗粒(ZnO NPs)在水中的稳定性。本文通过构建垂直潜流人工湿地,以腐殖酸(HA)作为DOM的代表物质,研究了1 mg·L^(-1) ZnO NPs和不同浓度HA(1、5、10、20和30 mg·L^(-1))共存下对人工湿地处理性能、堵塞程度以及微生物群落变化的影响。结果表明:低浓度(≤1 mg·L^(-1))HA溶液会促进ZnO NPs的团聚,而中高浓度(1~25 mg·L^(-1))HA溶液则产生相反的作用。ZnO NPs和HA共存会降低人工湿地的净化效果,尤其是1 mg·L^(-1) HA时,COD、氨氮和总氮的去除率分别下降了18.07%、19.94%和26.37%。连续投加1 mg·L^(-1) HA浓度和1 mg·L^(-1) ZnO NPs 60天后,人工湿地堵塞最严重,渗透系数下降67.5%。HA和ZnO NPs共存会影响微生物分泌胞外聚合物(EPS),当HA浓度为1 mg·L^(-1)时,EPS高达140.30±0.29 mg·g^(-1),而空白组仅为78.67±0.32 mg·g^(-1),这也是人工湿地堵塞严重的一个重要原因。此外,ZnO NPs和HA的加入会降低微生物群落的丰富度和多样性,并促进分泌EPS微生物(Thauera)的生长。研究结果可为人工湿地的堵塞机制提供新的解释。
The presence of dissolved organic matter(DOM) affects the stability of zinc oxide nanoparticles(ZnO NPs) in water.By constructing vertical subsurface constructed wetlands,taking humic acid(HA) as a representative substance of DOM,we examined the effects of coexistence of 1 mg·L^(-1) ZnO NPs and different concentrations of HA(1,5,10,20 and 30 mg·L^(-1)) on the treatment performance,clogging and microbial communities of constructed wetlands.The results showed that low HA concentration(≤1 mg·L^(-1)) could promote the agglomeration of ZnO NPs,while the medium-high concentrations(1-25 mg·L^(-1)) showed opposite effect.The coexistence of ZnO NPs and DOM would reduce the purification effect of constructed wetlands.At the concentration of 1 mg·L^(-1) HA,the removal efficiencies of COD,ammonia nitrogen and total nitrogen decreased by 18.07%,19.94%,and 26.37%,respectively.Under the condition of 1 mg·L^(-1) DOM and 1 mg·L^(-1) ZnO NPs,the constructed wetland was most seriously blocked,and the permeability coefficient decreased by 67.5% after 60 days.The coexistence of HA and ZnO NPs could affect the secretion of extracellular polymeric substance(EPS).The EPS concentration was as high as 140.30±0.29 mg·g^(-1) at 1 mg·L^(-1) ZnO NPs and 1 mg·L^(-1) HA,while that in the blank group was only 78.67±0.32 mg·g^(-1),explaining the clogging of constructed wetlands.In addition,the addition of ZnO NPs and HA reduced the richness and diversity of microbial community and promoted the growth of EPS-secreting bacteria(Thauera).The findings may provide a new explanation for the clogging mechanism of constructed wetlands.
作者
刘宇豪
孔范龙
李悦
王康
王文悦
王晓燕
王森
LIU Yuhao;KONG Fanlong;LI Yue;WANG Kang;WANG Wenyue;WANG Xiaoyan;WANG Sen(College of Environmental Science and Engineering,Qingdao University,Qingdao 266071,Shan-dong,China)
出处
《生态学杂志》
CSCD
北大核心
2023年第12期3019-3029,共11页
Chinese Journal of Ecology
基金
山东省自然科学基金项目(ZR2019MD042、ZR2020MD006)资助。
关键词
溶解性有机质
纳米氧化锌
人工湿地
堵塞
dissolved organic matter
zinc oxide nanoparticles
constructed wetland
clogging
