Natural Formation Of Nano-Silver And Its Effect On The Stability Of SBR System

In recent years,with the widespread application of artificial nanoparticles,the environmental pollution of artificial nanoparticles has received more and more attention.In addition,nature will also form a large number of natural nanoparticles through chemical,physical and other processes,and the amount of these natural nanoparticles produced is several orders of magnitude larger than artificial nanoparticles.Among them,nano silver is widely used.Revealing the formation,migration and transformation process of nano-silver in the water environment is of great significance for studying the environmental behavior of nanoparticles.At the same time,with the development of the global economy,the situation of natural water bodies being contaminated with oil is becoming more and more serious.Oil-contaminated water bodies need to be treated with wastewater before they can be discharged back into the natural environment.A large number of nanoparticles in the environment that it is unique physical and chemical properties may have an unpredictable effect on the biological treatment of wastewater.In order to address the above key scientific issues,this paper first takes natural nano silver particles(Ag NPs)as research objects,and pyrene(Py)as a typical petroleum pollutant;analyzes water quality parameters(humic acid concentration,p H value,temperature)On Py-Ag NPs,the reaction kinetics of Py-Ag NPs in natural water was discussed,and the corresponding kinetic model was established;Ag NPs were measured on Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus;Secondly,natural nanoparticles Ag NPs and typical artificial nanoparticles Zn O were put into a typical sewage treatment reactor,and the effects of nanoparticles on the processing efficiency of a Sequencing Batch Reactor(SBR)were investigated.The results are as follows:(1)Under the conditions of simulating natural light,explore the generation rules of nano-silver.It was found that Py can promote the generation of natural nano-silver;humic acid can also promote the production of natural nano-silver,but when humic acid and Py are present at the same time,the rate of natural nano-silver is lower than that of the two when they are alone.(2)Using Py as a typical petroleum pollutant in natural waters,it was found that in the concentration range of 5 ? 15mg/L,the content of humic acid was positively correlated with the generation rate of Ag NPs;within the range of p H 5 ? 9,natural nanometers The generation rate of silver increases with increasing p H;in the range of 25 ? 90 ° C,the generation rate of Ag NPs increases with increasing temperature;the change in the concentration of silver ions in the reaction was measured using inductively coupled plasma spectroscopy,It was found that when Py was not added,the amount of Ag NPs produced was 3.78 ?mol/L,and when Py was present,the amount of Ag NPs produced was 3.17 ?mol/L.Metal cations(such as sodium,potassium,magnesium,and calcium)affect the precipitation rate of Ag NPs.The change of Py content during the reaction was measured by high performance liquid chromatography.The antibacterial activity of Ag NPs against Gram-negative bacteria(Escherichia coli)and Gram-positive bacteria(Staphylococcus aureus)was discussed.(3)Different concentrations of Ag NPs and Zn O were put into the SBR reactor,and Methylene Blue(MB)was used as the target pollutant in the SBR reactor to investigate the effect of nanoparticles on the processing efficiency of SBR.Two typical strains(L1 and L2)were screened from activated sludge,and the change of the concentration of reactive oxygen species(Reactive Oxygen Species,ROS)in bacterial cells by nanoparticles was studied,it will rise over the time.