Study On The Preparation And Properties Of Ag/Zeolite Composited Antibacterial Materials

Although silver ion is of excellent antibacterial property, silver salt is easily oxidized and discoloured under light or in long storage and its antibacterial activity is therefore deactivited. Moreover, its antibacterial property may obviously get worse due to the precipitation of silver in contact with water. All those disadvantages make the application very limited. To solve above problems the materials with inner pores such as zeolite and silica gel are used as carriers to firmly support silver ion by physical absorption or ion exchanging. Compared with conventional organic antibacterial agents, inorganic ones are superior in terms of safety, antibacterial durability, wide antibacterial spectrum and heat resistance. Theresearch of antibacterial materials has become how to release antibacterial ions slowly and to improve their dispersion in and compatibility with matrix. Of many inorganic antibacterial agents (lAAs), silver-zeolite is becoming more and more popular. 4A zeolite is a porous crystalline material with porosity over 50%. The average diameter of pores is about 0.4nm, which is far greater than action or hydrated radius of silver or zinc ion. So 4A zeolite is chosen as carrier to prepare Ag/4A by ion-exchanging, which has perfect antibacterial performance and heat stability.In this paper, two kinds of IA As, single-ion exchanged zeolite (silver zeolite, zinc zeolite) and double-ion exchanged zeolite were prepared by ion exchanging with 4A and 13X zeolite as carriers respectively. The preparation conditions were investigated and optimized. The results show that the concentration of exchanging solution and pH value has great effect on exchanging amount. The antibacterial tests were carried out. The starting concentration of silver nitrate was 0.1N. The ions exchanging was carried out at 60 C for 4h with pH value controlled at 6.0-8.0. Asfor double-ion exchanged zeolite, the exchanging of zinc ions has little influence on that of the silver ions.The microstructure of antibacterial zeolite was investigated by XRD, FTIR, SEM, BET and particle size analysis, and antibacterial performance was tested according colony number. The primary conclusion is that the antibacterial performance of double-ion exchanged zeolite is superior to that of Ag/zeolite because of the conjugated of silver and zinc ions.