Study On The Photocatalytic Antibacterial Property And Antibacterial Mechanism Of Titanium Dioxide

Titanium dioxide(TiO2) is a kind of photocatalytic semiconductor material which has the advantages of high activity, good antimicrobial activity, good thermal stability, long-term effective, low prices and non-pollution and so on. So, It can be widely used in anti-fog, photocatalytic sterilization, water quality and soil decontamination, air purification, self-cleaning and so on many fields. Presently, Study on TiO2 has become crazy. The researchers are trying to prepare all kinds of useful the stability of physical and chemical properties and good photocatalytic properties of TiO2.TiO2 is research material which is prepared with new technology of mixing (non-metallic EDTA and citric acid) in the 90℃and take some characterization of it. In this experiment, At first, with the method of comparing the size and thin of plaque by dripping plate, the antibacterial action on bacteria such as E.coli, S.aureus, B.Subtilis and fungus such as S.epidermidis, C.albicaus with standard nano-TiO2 and homemade five kinds of TiO2 power was studied qualitatively. Then, according to the results of qualitative antibacterial, select four kinds of bacteria and set the appropriate bacterial concentration, the concentration of TiO2 and the photocatalytic sampling time, The photocatalytic antibacterial properties of standard nano-TiO2 and homemade five kinds of TiO2 was studied quantitatively with counting way. Finally, select the behalf strains of S.aureus and the behalf of TiO2, The effects of the initial concentration of bacteria and the concentration of TiO2 on the impacts of antibacterial action of TiO2 were studied.The structure and morphology of bacteria before and after antimicrobial treat is scanned with electron microscopy which is been to explore the principle of photocatalytic antibacterial of TiO2 preliminaryly. The results are as follows:With TiCl4 as the raw material, using low-temperature aging method, There were four kinds of mixed crystalline form of TiO2 powder which were prepared with adding EDTA and citric acid and a kind of pure rutile phase of TiO2 powder which was prepared without adding additive. Scanned with electron microscopy, It showed that the size of standard TiO2 was nano-scale, the surface area was large, the dispersion was poor, The size of Self-made TiO2 was micro-scale, the surface area of them was small. Comparing the five kinds of self-made TiO2, The non-doped TiO2 was the smallest size and the largest surface area of all. Photocatalytic degradation of methyl orange experiments showed that the photocatalytic performance was poor of product without adding additives and good of product with adding additives.The results of qualitative and quantitative disinfection experimental all show:It was sensitive to 365nm,20W UV light for Candida albicaus. It is not traumatic to E. coli, S.aureus, S.epidermidis under only this ultraviolet light. It is no bactericidal effect under only the conditions of TiO2. The effct of antibacteria is obvious under TiO2 with UV excitation.The effect of photocatalytic antibacterial of standard nano-TiO2 is stronger than self-made five kinds of TiO2. And the action of antibacterial on the fungi is stronger than on bacteria.In addition, The quantitative antibacterial test's result still show:the action of antibacteria of the six TiO2 on this four kinds of bacteria are S.aureus≈E. coli>S.epidermidis>C.albicans. The antibacterial effect of TiO2 prepared with adding EDTA and citric acid is not better than that prepared without adding Additives. There is an optimum value of the dosage of TiO2 catalyst. which is 0.8g/L.It is obvious effct that the bacteria concentration and the concentration of TiO2 act on the effct of TiO2 photocatalytic antibacterial and The impact is different for different TiO2.The structure and morphology of bacteria before and after antimicrobial treat is scanned with electron microscopy, we can see that the photocatalysis of TiO2 can destroy the surface structure of bacteria or damage the internal structure of bacteria by generated active oxidation material entering into bacteria. Eventually, lead to bacterial inactivation.