The Design Of Visible Light Catalytic Antibacterial Materials And The Study Of Their Structure-activity Relationship

Pathogenic bacteria caused drinking water security incidents in recent years,which has aroused people's wide attention.For such security issues,many researchers explored a variety of methods,including semiconductor photocatalytic sterilization.This is an emerging sterilization technology with the sunlight as the driving force.It is aroute of high efficiency,broad spectrum and durable,not easy to create the medicine bear and no secondary pollution of sterilization technology of green environmental protection.As a typical semiconductor,titanium dioxide has attracted lasting concern due to its low toxicity,low cost,excellent chemical stability and high activity.However,as a result of its wide band gap,UV light excitation and low quantum efficiency?QE?,the practical application of Ti O₂ has been prohibited,including pollutants purification,antibacterial and so on.For these reasons,the following three routes were proposed:?1?Develop new visible light catalytic materials preparation technology by modifying the pure CoO modification,improve the utilization efficiency of sunlight,and the materials used in the purification of the hospital environment highly pathogenic bacteria,to replace traditional antimicrobial agents;?2?Design of nano reticular photocatalytic materials,the using of material itself the capture of the mesh structure is conducive to against bacteria,thus increase the contact time,catalyst and bacteria to develop materials photocatalytic antibacterial activity;?3?Design nanorod low-weight-molecular carbon nitrides photocatalytic antibacterial polymer materials.The material stability,bactericidal activity and its photocatalytic antibacterial mechanism is worth of further development.In view of the above ideas,this paper has carried out the following work:?1?Supercritical solvothermal and photo-reduction preparation of Ag/CoO-N with its antibacterial performanceIn this section,we prepared CoO-N via supercritical solvothermal approach using cobaltous nitrate and ammonia water as copper.On this basis,Ag/CoO-N complex visible light catalyst was synthesized by visible light reduction with silver nitrate as silver source and methanol as sacrificial agent.XRD,SEM and XPS characterizations results showed that supercritical slovothermal treatment resulted in the mesoporous structure,small crystal size,large special surface areas,high crystallinity and high visible-light absorption.Thus,in virtue of SEM,ICP and TOC characterizations to study antibacterial process,the phenomenon of bacterial autolysis and self-healing was investigated.The photocatalytic materials showed excellent activity in the process of destroying acimeshobacter baumannii,effectively avoiding the defects of bacteria resistant by antibiotics with visible-light irradiations??>420nm?.?2?g-C₃N₄ nanomesh in visible light photocatalysis killing escherichia coliAlthough the photocatalyst developed at present shows good bactericidal ability in the visible light wave region,the exposure of the catalyst to bacteria is random and transient and can not effectively capture bacteria.In this thesis,nanoscale g-C₃N₄photocatalytic materials were designed and prepared.Because of its network structure,the catalyst can effectively capture bacteria,increase the contact time between the materials and bacteria,and improve the photocatalytic activity of the materials.The physicochemical properties of the catalysts were characterized by XRD,TEM and XPS,and the antibacterial process was studied by means of SEM,ICP and Zeta potential.The photocatalytic material showed excellent activity in killing Escherchia coli and the process of bacteria being captured by the material investigated.?3?Low-weight-molecular carbon nitrides nanorod with visible light photocatalytic antibacterial performanceAlthough g-C₃N₄ nanomesh photocatalyst in the visible light wave band has the very good kill e.coli features,recent studies have found that low-molecular-weight carbon nitrides compared with g-C₃N₄ nanosheet has better photocatalytic activity.For bacteria,the rod-like structure is conductive to exposing more active sites,anchoring bacteria,and improving photocatalytic activity.In this paper,the rod-like tripolyamines were designed and prepared.The physicochemical properties of the catalysts were characterized by XRD,SEM and TEM.The bactericidal properties of the catalysts under visible light were also investigated.