SBR中纳米氧化锌和四环素复合投加系统对污泥胞外聚合物的影响

Effect of combined addition of ZnO nanoparticles and tetracycline on extracellular polymeric substances of sludge in SBR system

为研究氧化锌纳米颗粒(ZnO-NPs)和四环素(TC)对SBR系统内活性污泥胞外聚合物(EPS)特性的响应变化,在模拟室外光照条件下,考察了递增浓度ZnO-NPs和TC单独或复合投加方式下对EPS中蛋白质和多糖的影响。结果表明:ZnO-NPs、TC和复合投加系统中EPS的蛋白质含量均明显高于多糖,在各系统中,低浓度的投加量对蛋白质和多糖的含量改变无明显影响;随着浓度的递增和反应周期的延长,相比于空白组,ZnO-NPs系统中的蛋白质和多糖含量分别下降了33.58%和64.75%;TC和复合投加系统中蛋白质含量分别升高了57.86%、68.58%,多糖含量分别下降了43.60%和40.38%,且2个系统蛋白质和多糖含量变化趋势相似,因此,判断复合投加系统可能受TC影响较大。FT-IR分析显示,ZnO-NPs、TC和复合投加系统主要对EPS中蛋白质和多糖中的—OH、—NH2、C==O、C—OH及C—O产生影响。3DEEM分析表明,EPS中蛋白质基团受到主要影响。该研究可为纳米颗粒和抗生素共存情况下对污泥EPS的影响提供依据。

In this study,the effects of zinc oxide nanoparticles(ZnO-NPs)and tetracycline(TC)on the property variation of extracellular polymer substance(EPS)in activated sludge of SBR system were determined.Under the simulated outdoor illumination conditions,the effects of gradually increasing concentrations of ZnO-NPs or TC alone and their combined system on protein and polysaccharide in EPS were investigated.Results showed that the protein content of EPS in ZnO-NPs,TC or their combined system were significantly higher than the polysaccharide content,while low doses of these additives had no significant effect on the variations of protein and polysaccharide contents.With the increase of additives contents and the extension of the reaction cycle,compared with the control system,the protein and polysaccharide contents in the ZnO-NPs system decreased by 33.58%and 64.75%,respectively.In the TC or combined system,the protein content increased by 57.86%and 68.58%,while the polysaccharide content decreased by 43.60%and 40.38%,respectively.The similar change trends of protein and polysaccharide content in TC and combined systems could imply that the combined system may be more susceptible to TC.FT-IR analysis showed that ZnO-NPs,TC and combined system mainly affected the—OH、—NH2、C==O、C—OH and C—O in the proteins and polysaccharides of EPS,and 3D-EEM indicated that the three systems mainly affected the protein function groups of EPS.This study can provide research basis for the effect of nanoparticles and antibiotics coexistence on sludge EPS.