Study On The Preparation And Antibacterial Application Of Silver Nanoparticles

Silver is one of the important precious metals. It has been widely used as antibacterial material, medical material, optical material, ornamental material, catalytic material, electrical and electronical materials, etc. Due to their peculiar properties caused from the volume effect, the surface effect, the quantum dimension effect, and the macro-quantum tunnel effect, the silver nanoparticles might become to the prospective important materials applied potentially in many field.There are many methods to prepare silver nanoparticles, in which the liquid-phase chemical reduction process is more controllable and easier in large-scale production. In this study, the silver colloids were prepared by the chemical reduction in liquid phase with silver nitrate, sodium hypophosphite (as reducer), sodium hexametaphosphate (as disperser), and polyvinylpyrrolidone (as protective agent). Through controlling reaction condition, the spheroid, dispersible and the stable silver colloids were prepared, and the optimum technologic has been summarized. The dispersible and stable silver colloid was synthesized at 50℃and reaction for 1 hour in the system of C(AgNO3)=1.0 mol/L, C(NaH2PO2·H2O)=0.1 mol/L, 2~3 times theoretical dosage of Na2PO4, m(PVP)/m(AgNO3) = 1.0~1.2, m([NaPO3]6)/ m(AgNO3)= 0.1~0.2, pH=1~2. The silver nanoparticles were obtained through desiccation of the colloid, and were characterized by XRD and TEM. The results showed that the product was the spherical silver particles with the mean size about 7~10 nm and without impurity almost.The antibacterial and bacteriostatic effects of silver nanoparticles to two index-bacteria (Escherichia coli, Bacillus subtilis) have been studied qualitatively and quantitatively. The antibacterial experimental results showed that the silver nanoparticles could effectively kill and...