Study On The Composite Material Of Nano-Titanium Dioxide/Montmorillonite And Its Antibacterial Performance

Preparation of efficient and stable laden-titanium dioxide photocatalyst is one of the research focus of photocatalysis oxidation technology in recent years. High efficient catalytic activity TiO₂/montmorillonite composite photocatalyst was prepared by supporting nano-TiO₂ in the interlayer and on the surface at a lower temperature with montmorillonite as support which has strong ion exchange property and layered structure characteristic. Three aspects of preparation of TiO₂/montmorillonite environmental mineral materials, its antibacterial performance and preliminary application in dope were researched in order to provide theoretical basis for the application of TiO₂ photocatalysis antibacterial agent in latex coating.1. Preparation and characterization of nano-titanium dioxide/montmorillonite composite photocatalystTitanium sol was prepared with the precursor of Ti(OC₄H₉)₄, C₂H₅OH, HNO₃ (1mol/L) and CH₃COOH by using sol-gel technique. The volume ratio of these reactants was 5: 25: 12: 0.4. The effect of theoretical loading amount, immobilization temperature, drying temperature and calcination temperature on photocatalytic activity of the composite photocatalyst is studied. The optimum synthesis conditions to prepare TiO₂/montmorillonite composite photocatalyst were obtained from the experimental results as follows: the mass concentration of montmorillonite suspension was 3%, the ratio of Ti(IV) to montmorillonite was 15 mmol/g, the immobilization temperature is 25℃and the drying temperature is 70℃. This photocatalyst has high efficient photocatalytic activity. The rate of decoloration for azo dye of TiO₂/ montmorillonite composite photocatalyst can reach 93.40% after 1 hour of the reaction time when the concentration of photocatalyst is 2g/L.X-ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and Fourier Transform Infrared Spectrum (FTIR) technologies were adopted to characterize and analyse the crystal structure and molecular configurations and surface appearances of the composite system. The results showed that TiO₂ was existed as anatase and rutile mixed-crystal phase which was uniformly covered on the surface of the montmorillonite in the composite system with the average crystal size of 6.98 nm. The ratio of anatase in the TiO₂ is 92.34% and rutile is 7.65%. The TiO₂ has been inserted into the interlayer of montmorillonite.2. The antibacterial performance of nano-titanium dioxide/montmorillonite composite photocatalystEscherichia coli and Staphylococcus aureus were selected as the target of different Gram type of bacteria to investigate the antibacterial performance dioxide/montmorillonite composite system. The results showed that dioxide/montmorillonite composite photocatalyst has efficient antibacterial performance to both Escherichia coli and Staphylococcus aureus. The bactericidal rate can reach 99.9% after 1 hour in light. Escherichia coli has exhibited higher sensitivity than Staphylococcus aureus. The titanium dioxide/montmorillonite displays certain residual disinfection effect in a period of time after the end of the illumination. The minimum inhibitory concentration of the dioxide/montmorillonite composite photocatalyst to Escherichia coli and Staphylococcus aureus are 88.89% and 76.67% respectively which reached the requirement of the Society of Industrial technology for Antimicrobial Articles(SIAA) to antibacterial performance of inorganic antibacterial agent.The preliminary application of dioxide/montmorillonite composite photo-catalysis antibacterial agent in latex coating were researched. It's antibacterial performance was evaluated by a relevant standard. The bactericidal rate of the coating film to Escherichia coli and Staphylococcus aureus can reach 88.89% and 76.67% respectively. The antibacterial performance of the coating film can be improved with the increase of the dosage of antibacterial agent.