Study Of Preparation Of Silver-loaded Silica And Its Antibacterial Activity

This paper studies the preparation of silver-loaded silica by chemical reduction and has discussed the best preparation conditions of silver-loaded silica reduced by sodium citrate, basic glucose and hydrazine, respectively. The best conditions of sodium citrate as reducer are: Na3C6H5O7:AgNO3=2:1(molar ratio), reaction temperature-100℃, reaction time-3h; The best conditions of basic glucose are: C6H12O6:AgNO3=2:1 (molar ratio), [NaOH] = 3.2×10-2 mol/L, reaction temperature-60℃, reaction time-10min ; The best conditons of hydrazine are: N2H4·H2O:AgNO3=6:1(molar ratio), reaciton time-20min, reaction temperature-room temperature(20℃). In the reaction system the concentration of silver nitrate is fixed as 1.77×10-2mol/L. Then silver amount loaded on silica is approximately 3.0wt% by different reducers. According to test of antibacterial performance, all silver-loaded silica reduced by three different reducers show good antibacterial activity. Chemical reduction is better than calcination because of its simple process, high utilization of silver nitrate and fine antimicrobial activity of products. Silver-loaded silica sol is reduced by basic glucose and its antibacterial performance is excellent in despite of low silver-loaded amount. Sol can be dispersed in fabric, fiber, dope, ceramic and so on. There is bright future in its application. A little copper or zinc is loaded on silica powder instead of silver in order to reduce the cost. The result of antibacterial tests indicates that small amount of copper or zinc in silver-loaded silica doesn't lower the powder's antibacterial effects so much. Antibacterial effect of copper is stronger than that of zinc. The paper has used Density functional theory (DFT) B3LYP to fully optimize the absorption system of [Ag+-SiO2] and [Ag-SiO2] and discussed the...