Antibacterial Activities Of Zn?Zn/Ce?Zn/Y And B Doped TiO₂ Nano-materials And Preparation Of Antibacterial Ceramic

In recent years,semiconductor photocatalysts have received increasing attention because of their commendable properties in air-cleaning,antimicrobial and self-cleaning.TiO₂ is the most widely used photocatalysts thanks to its chemical stability,nontoxic and efficient photosensitivity among a large number of photocatalysts.However,the application of TiO₂ in the field of photocatalysis is limited by its low quantum efficiency and low utilization rate of visible light.Aiming at the disadvantage of low utilization rate of visible light for TiO₂,here we focus on improving the photocatalytic antibacterial activity of TiO₂ under the visible light irradiation through doping ions.Zn/Ce,Zn/Y and B-doped TiO₂ nano-materials were prepared by sol-gel method using Tetrabutyl titanate[TBOT]and ethyl alcohol as raw materials.Crystal phases,chemical composition and optical absorption properties of TiO₂ were examined by XRD,TEM,XPS,UV-Vis-DRS,PL and FT-IR.The antibacterial activities of the prepared materials were investigated by inhibition zone method and flask oscillation method.Antibacterial ceramics were prepared using the optimal experimental parameters of Zn/Ce-TiO₂ and Zn/Y-TiO₂.The main results of this work are as follows:Study on preparation of TiO₂ nano-material and its antibacterial activity.The particles size of prepared TiO₂ by sol-gel method is in nano scale.With the calcination temperature from 500 to 800 0C,crystalline phases transition from anatase TiO₂ to rutile TiO₂ is found,and the phase transformation temperature is 600 ?.TiO₂ nano-material in the UV region has strong light absorption capacity,but in the visible region,almost no absorption.The prepared TiO₂ nano-materials have no antibacterial activities to C.albicans?ATCC 10231?,E.coli?ATCC 25922?and S.aureus?ATCC 6538?under the visible light irradiation.Study on antibacterial activities of different zinc sources doped TiO₂ nano-materials?Zn-TiO₂?.Zn?NO₃?₂-TiO₂,Zn?Ac?2-TiO₂,ZnCl2-TiO₂ and ZnSO₄-TiO₂ nano-materials were prepared and the effects of zinc content and calcination temperature on the antibacterial activities of Zn-TiO₂ were systematically studied.The result show,the effect of zinc ions doping content on phase's composition of Zn-TiO₂ is not significant.The crystal phase transformation temperature is 700? for Zn?NO₃?₂-TiO₂ and Zn?Ac?2-TiO₂.ZnCl2-TiO₂ calcinated at 500 ? begins to appear a small amount of rutile.ZnSO₄-TiO₂ nano-material calcinated at 500 0C exhibits anatase TiO₂ and ZxSO₄;calcinated at 800?,crystal phases of ZnSO₄-TiO₂ transform to rutile TiO₂,Zn2Ti3O8,Zn2TiO₄ and ZnO.S may exist in the form of SO₃ and then volatilize.Absorption edges of Zn-TiO₂ move to visible region.The antibacterial results show that in the same amount of zinc ions doping and at the same calcination temperature,the order of antibacterial activities of Zn-TiO₂ nano-materials with different zinc source doped is ZnSO₄>Zn?NO₃?₂>Zn?Ac?2>ZnCl2.Calcination temperature from 500 to 800 ?,the antibacterial activities of Zn-TiO₂ nano-materials decrease gradually.In the dark,antibacterial activities of Zn-TiO₂ nano-materials are weaker than those in the visible light irradiation.Study on antibacterial activities of zinc and cerium co-doped TiO₂ nano-materials?Zn/Ce-TiO₂?.The effects of zinc and cerium doping content,calcination temperature,illumination time,dark condition and SO₄2-on the antibacterial activities of Zn/Ce-TiO₂ nano-materials were systematically studied.The effect of zinc and cerium ions doping content on phase's composition of Zn/Ce-TiO₂ calcinated at 700 ? is not significant.The main crystal phases are anatase TiO₂,ZnTiO₃,CeO₂ and rutile TiO₂.With the amount of Zn and Ce ions increasing,absorption edges of Zn/Ce-TiO₂ gradually move to visible light region.Crystal phase transformation temperature is 700?.The addition of SO₄2-changes the phase's composition of Zn/Ce-TiO₂.Calcinated at 500?600 ?,crystal phases of Zn/Ce/SO₄2--TiO₂ are anatase TiO₂,Ce?SO₄?2,ZnSO₄ and Zn?OH?2.Calcinated at 700?800 ?,crystal phases of Zn/Ce/SO₄2-TiO₂ are anatase TiO₂,ZnS,ZnTiO₃,CeO₂ and rutile TiO₂.Visible light absortion intensity of Zn/Ce/SO₄--TiO₂ calcinated 500 ? is significantly increased.The antibacterial results show that antibacterial activities of Zn/Ce-TiO₂ increase firstly and then drop with Zn and Ce ions doping content and calcination temperature increasing.As using 10 mL of TBOT to prepare TiO₂ materials,the optimal doping amount of Zn ions and Ce ions are 0.002 mol and 0.003 mol,respectively;the optimal calcination temperature is 600 ?.In the dark,antibacterial activities of Zn/Ce-TiO₂ nano-materials are weaker than those in the visible light irradiation.SO₄2-ions doping improve antibacterial activities of Zn/Ce-TiO₂ nano-materials in the dark.Study on antibacterial activities of zinc and yttrium co-doped TiO₂ nano-materials?Zn/Y-TiO₂?.The effects of zinc and yttrium doping content,calcination temperature,illumination time and dark condition on the antibacterial activities of Zn/Y-TiO₂ were systematically studied.The effect of zinc and yttrium ions doping content on the phase's composition of Zn/Y-TiO₂ calcinated at 700 ? is not significant.The main crystal phases are anatase TiO₂,Zn2Ti3O8 and Y2Ti2O7.Crystal phase transformation temperature is 800 ?.Absorption edges of Zn/Y-TiO₂ gradually move to visible light region.The results show that the antibacterial activities of Zn/Y-TiO₂ nano-materials are improved under the visible light irradiation with the increase of the amount of zinc and yttrium ions,but there is the best value.The order of antibacterial activities of Zn/Y-TiO₂ nano-mateirals obtained at different calcination temperatures is 700 ?>600 ?>800 ?500?.In the dark,antibacterial activities of Zn/Y-TiO₂ nano-materials are weaker than those under the visible light irradiation.Study on antibacterial activities of boron-doped TiO₂ nano-materials?B-TiO₂?.The effects of boron content,calcination temperature and glycerol doping on the antibacterial activities of B-TiO₂ were systematically studied.Calcinated at 500 ? and 600 ?,the main crystal phase of B-TiO₂ is anatase TiO₂;calcinated at 700 ?,a small amount of rutile TiO₂ appear;B related phase is not found.XPS analyses indicate that,partial boron dopant is incorporated into the TiO₂ lattice through occupying the position of oxygen atom or embedded into the interstitial TiO₂ structure,and others are present as B2O₃.The addition of glycerol is beneficial to decrease grain size,increase the specific surface area and enhance light absorption for B-TiO₂.The antibacterial results show that the B-TiO₂ nano-materials have good inhibitory effect but no antibacterial activities under the visible light irradiation.Glycerol doping can improve antibacterial activities of B-TiO₂ nano-materials.Study on the preparation of Zn/Ce-TiO₂ and Zn/Y-TiO₂ antibacterial ceramics and their antibacterial activities.The effects of coating thickness,coating layer,and calcination temperature on the antibacterial activities of antibacterial ceramics were systematically studied by the film contact method.After coating,there is no visual difference between the surfaces of antibacterial ceramic and control ceramic.With the increase of coating layer,content of Ti,Zn and Ce increase.Antibacterial results show that the antibacterial activities of antibacterial ceramics are the best with 20 ?m coating thickness,two coating layers and calcination temperature at 600 0C.Comparison of antibacterial activities of Ce-TiO₂,Zn/Ce-TiO₂,Y-TiO₂,Zn/Y-TiO₂ and B-TiO₂ nano-materials.Antibacterial results show that the prepared Ce-TiO₂ and Y-TiO₂ nano-materials have no antibacterial activities.The order of antibacterial activities of Zn/Ce-TiO₂,Zn/Y-TiO₂ and B-TiO₂ nano materials is Zn/Y-TiO?Zn/Ce-TiO₂>B-TiO₂.