Preparation Of Nanometer SiO₂ Inorganic Antimicrobial

Ag-carried nanometer SiO₂ and Cu-carried nanometer SiO₂ were prepared by ion adsorption using nanometer SiO₂ as carrier and Ag⁺ or Cu²⁺ as antibacterial active element. The behavior of nanometer SiO₂ adsorbing Ag⁺ or Cu²⁺ was investigated. It was founded that pH, Ag⁺ amount appended, the grain size and the surface area of nanometer SiO₂ were major factors affecting Ag⁺ amount adsorbed, and when pH was between 9 and 11, Ag⁺ amount appended was between 3% and 5%, the grain size of nanometer SiO₂ was 15nm, the surface area of nanometer SiO₂ was 300m²/g, reaction time was between 30 and 60min and reaction temperature was between 20 and 40℃, optimal Ag⁺ amount adsorbed was attained, and that Cu²⁺ amount appended was an major factor affecting Cu²⁺ amount adsorbed in pH10 ammonia solution. The microstructure of Ag-carried nanometer SiO₂ was characterized by XRF, XRD, XPS, chemistry analysis method and TEM. The microstructure of Cu-carried nanometer SiO₂ was characterized by XPS. The results showed that the state of SiO₂ was amorphous and the state of Ag was m·Ag₂O·nSiO₂ when the sample which had adsorbed 38.6mg/g Ag⁺ was sintered at 700℃, and the state of Cu was m·CuO·nSiO₂ when the sample which had adsorbed 63 mg/g Cu²⁺ was sintered at 500℃. The performance of dissolving out Ag⁺, antibacterial performance, lasting antibacterial performance, colour stabiltity, thermal stability and acid and alkali -resistant performance of Ag-carried samples were investigated. It was founded that the sample, which was sintered at 700℃and had adsorbed 38.6mg/g Ag+ amount, have nicer performance of dissolving Ag+, excellent and lasting antibacterial performance, definite colour stabiltity, nicer thermal stability and acid-resistant performance, and that Cu-carried nanometer SiO2 had excellent mildew-resisting ability. Antibacterial performance of the samples unwrapped and wrapped was tested with Escherichia coli and Staphylococcus aureus in Guangdong Microorganism Test Center. The result showed that MIC of the two sanples unwrapped was 75mg/L and MIC of the two sanples wrapped was 50mg/L. Four samples had excellent antimicrobial ability. The result of mildew-resisting test that Cu-carried nanometer SiO2 was excellent in resisting mildew.