| With the development of social economy,the problem of water shortage and water pollution has become increasingly prominent,which has become one of the constraints of social sustainable development.Wastewater reuse has become the main way to solve the problem of water shortage and water pollution.However,there are a lot of microorganisms in the process of wastewater reuse,especially some pathogenic microorganisms will contact with people directly or indirectly,which will lead to water borne diseases.Although the traditional disinfection technology has a significant effect,it also has some problems such as disinfection by-products,light resurrection and so on.As a new material for environmental remediation,nano zero valent iron has the characteristics of small volume,large specific surface area,high reactivity,and good removal effect on virus and microorganism.However,the aggregation of nano zero valent iron leads to the decrease of specific surface area of particles,which greatly limits the further application of nano zero valent iron.Bacterial cellulose membrane is a new kind of multi-functional nano microbial material,which has a unique three-dimensional structure.It is composed of ultra-fine nano as a network.It can be used as a template of composite nano materials to protect and restrict nano particles,to a certain extent,prevent the agglomeration of generated nano particles,and improve the problems of loss,agglomeration and recovery of nano materials.Therefore,a novel bacterial cellulose membrane loaded nanometer zero valent iron(BC NZVI)material was prepared in this paper,and its inactivation characteristics and mechanism for phage were explored as follows:(1)The nanoparticle zero vale nt iron composite was prepared by in-situ reduction method.The structure and morphology of the composite were characterized by SEM,XRD,XPS and ICP.The results show that the loading amount of nanometer zero valent iron increases with the increase of ferrous sulfate concentration,so the loading amount of nanometer zero valent iron can be controlled by changing the ferrous sulfate concentration.However,when the concentration of ferrous sulfate increases to a certain extent,the nanoparticle will be overloaded,the particle size will become larger and agglomerate.(2)MS2 phage was selected as the model virus to explore the relationship between the inactivation rate of MS2 phage and the nano zero valent iron load,p H,the initial concentration of MS2 phage,the dosage and temperature of the composite.The results show that the composite prepared by ferrous sulfate solution with lower concentration has better inactivation effect,and the removal rate is close to 4 log in 5 minutes.The removal rate is positively related to p H,initial concentration,dosage and temperature,but the sensitivity to the environment is reduced,and the overall inactivation efficiency is improved.(3)The morphology and products of the reaction were observed by SEM,XRD and XPS,and the effect of free radicals was explored by adding free radical trapping agent.Finally,the stability of the material was explored by the rate of inactivation of phage MS2 under different aging time.The results showed that after the inactivation reaction,the oxidation degree of the composite prepared at the low concentration of ferrous sulfate was the lowest,which indicated that bacterial cellulose membrane could alleviate the oxidation process of nano-sized zero valent iron.However,for the study of free radicals,it was found that the active oxide(· oh and · O2-)played a leading role in the inactivation of MS2,which was due to the loss of phage’s infection ability;the results of aging test showed that the inactivation rate of the composite did not decrease after 28 days,which indicated that the prepared bacterial cellulose membrane loaded nano zero valent iron composite could be preserved for a long time without affecting its performance in the dry environment,and the oxidizability of nano zero valent iron was inhibited Improved stability. |
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