Preparation And Characterization Of Antibacterial Activated Carbon Supported With Silver Obtained Via Reduction Methods

It was a common concern about potable water deep purification due to the serious increasing water pollution. Activated carbon adsorption is widely used for the elimination of organic and inorganic pollutants form aqueous phase, which has been recognized as one of the most versatile process among various traditional water treatment processes. Activated carbon (AC) is biological compatibility and chemistry stability, when it is used for water treatment, microorganism in water is easily adsorbed and breed on that, AC itself become an center for microorganism reproduces, causes the quantity of microorganism increase remarkably; Moreover, some microorganisms adsorbed on AC can transform ammonia to nitrite and cause the problem of nitrate pollution. In order to overcome the above shortcomings, AC supported with silver was widely used. However, realizing the high antibacterial activity and the silver control release of Ag/AC is a challenge in this field.Activated carbon-silver composite (Ag/AC) for antibacterial behavior with capability of controlling silver release was prepared by NaBH4 reduction method and silver acetate vacuum impregnation method, respectively. The antibacterial activity towards E.coil and resistance of water erosion was investigated through a point of view of water purification. Surface area and porosity analyzer, Scanning electron spectroscopy (SEM) and X-ray diffraction (XRD) were used to characterize the surface morphology and pore properties.As an experiment result, silver of Ag/AC prepared by NaBH4 reduction method was deposited on AC in the state of Ag0. The content of silver supported, specific surface area, nucleus formation and growth mechanism, particle size and distribution of the generated silver particles were determined by the concentration of the aqueous solution of AgNO3. With the increasing of AgNO3 solution concentration, the activity of the obtained Ag/AC changed from non-active to inhibitory and then to high antibacterial. Ag/AC supported silver content of 2.70 wt% killed all the concentration of 2×106 CFU/mL of E.coil. However, it showed high resistance to water erosion that silver loss was 21.1% in 600 h for surging.Activated Carbon-silver Composite (Ag/AC) for antibacterial behavior with controlling silver release was prepared by silver acetate vacuum impregnation method. Ag0 of Ag/AC prepared by silver acetate vacuum impregnation method was deposited on AC symmetrically. The content of silver supported and particle size were increased by the increasing of the concentration of CH3COOAg, while specific surface area, total pore volume and average pore size were decreased. Ag/AC prepared with silver content of 0.97 wt% which killed 107 CFU/mL concentration of E.coil in 120 min exhibited the similar antibacterial activity for E.coil with that prepared by traditional impregnation method. However, the silver loss of the Ag/AC prepared with silver content of 0.97 wt% was 37.6%, showing much higher resistance to water erosion.Compared the performance of Ag/AC prepared by NaBH4 reduction and silver acetate vacuum impregnation method, it is obvious that silver acetate vacuum impregnation method was superior. High antibacterial activity and control silver release can be simultaneously realized by the silver acetate vacuum impregnation method, which indicated that is a promising potential method for Ag/AC.