Study On Silver-loaded Inorganic Antibacterial Nano-composite

With the increase of people's life standard, how to control and restrain the growth and reproduction of deleterious bacterial becomes an important topic and has absorbed a lot of attention in the past years. Inorganic antimicrobial agents have many advantages and commercial potentials, it became a pivotal field in antibacterial research. In this paper, a series of research have been done on silver-loaded zeolite antibacterial agent, including optimizing technical parameters of preparation antibacterial agent, measuring slow-releasing property and antibacterial performance, testing the heat stability of antibacterial agent by thermogravimety analysis (TG) and differential thermal analysis (DTA). Silver state in zeolite matrix was investigated by X-ray photoelectron spectrum (XPS). The influence of heat treatment temperature on Ag state in matrix was studied with the help of X-ray diffraction (XRD) and diffuse reflection spectrum (DRS). Furthermore, technical parameters of antibacterial PP polymer with antibacterial agent added was optimized and the influence of them on appearance of polymer was also investigated.In optimizing ion-exchange process, an appropriate set of technical parameters has been obtained as follows: concentration of AgNO3 ranges between 0.03mol/L and 0.08,pH value of reaction system ranges between 3 and 8,reaction temperature is about 50℃ and reaction time ranges between 3h and 5h. MIC test shows that: concentration of AgNO3 has great influence on antibacterial performance of powder and pH value of reaction system nearly has no effect on it,but it has a great influence on thermo -stability of antibacterial agent. With the increase of concentration of AgNO3, the powder's antibacterial performance goes up. With the help of XPS we found that silver appears ion state in cavities and holes of matrix, when not undergone heat treatment. Results of XRD and MIC test shows: antibacterial agent still keeps good antimicrobial after 400℃ heat treatment for 2 hours. But antimicrobial performance descend, when heat treatment temperature goes up to 800℃.In order to explore the relationship between heat treatment and antibacterial performance, we resorted to DRS and found Ag+ tends to diffuse to the out surface and form nanoparticles. As we know, Ag particles are not as good as Ag+ in antibacterial test. Antibacterial powder was added to PP polymer, It was found that antimicrobial rate after contacting with Staphylococcus aureus 24h meets 98.8% and E.Coli meets 99.9%, which is higher than the standard-90% and meet the requirement of utility.