Preparation Of A New Type Of Inorganic Antibacterial And Evaluation Of Its Antibacterial Activity

A new type of Ag-carrying inorganic antibacterial was prepared and its antibacterial activity was evaluated in this thesis.Firstly, mesoporous pure silica molecular sieve was prepared with template method, which was used as the carrier of silver. It was proved that the template is formed by the cooperation of the silica source and the surfactant CTAB rather than by the surfactant CTAB along before the silica condensed on the micelle surfaces. The influence of surfactant concentration, pH value, crystallizing temperature, crystallizing time and calcining temperature on the material's surface area, morphology and order were also discussed in turn in the process of sol forming, gelation and aging and drying to get rid of template. The optimized conditions for preparation were established as follows: the concentration of the surfactant solution should be higher than 1wt% and the suitable concentration was 3wt%; the pH value should be controlled between 10 and 12; the solution should be kept under the temperature of 125℃ for 24h for crystallizing and the temperature for template removal should be between 600-800℃.Furthermore, the fractal dimension of the structure of the mesoporous pure silica molecular sieve and active carbon was investigated with the box-counting algorithm. It was shown that the molecular sieve structure was fractal and its fractal dimension was about 2.6, higher than that of active carbon (2.21 or so), corresponding with the higher specific area of the molecular sieve than that of active carbon Thus it is supposed to build up the connection between the fractal dimension and the nature of porous structure.Then, Ag-containing antibacterial materials based on the mesoporous pure silica molecular sieve was obtained by dipping the carrier into the silver solution. Some influence factors on silver content of antibacterial were discussed. It was found that smaller raw material particles size, negative pressure and longer soaking time in the step of silver coating would contribute to a higher Ag content of silver containing silica. The prepared products were proved to be having silver content of about20mg/g higher than that of Ag-carrying coral reefs.The experiments measuring width of antibacterial "halo" showed that this kind of materials could effectively restrain growth of Escherichia coli and Bacillus subtilis. The measurement of bactericide ratio showed that this antibacterial could prevent 95% of Escherichia coli and Bacillus subtilis from surviving. After immersed in the water for 96h it kept a bactericide ratio of 99%, and when it was repeatedly used for 3 times, its bactericide ratio was 75%.