Surface Transition by Solvent Washing Effects and Biological Properties of Metal Treated Activated Carbons

摘要

Metal treated activated carbons are prepared using various metals.Adsorption behaviors,morphologies,as well as antibacterial effects of metal treated samples are compared before and after solvent washing.Adsorption isotherms are used to characterize the porous structure of metal treated activated carbons before and after the solvent washing with acetone or ethyl alcohol.From these data,it is noticed that the changes in physicochemical properties of metal treated activated carbons depend on the solvents employed.Similar results are observed from BET data obtained from nitrogen adsorption isotherms.From scanning electron microscopy (SEM) studies,the changes in shape and size of metal particles are observed after the samples are washed with solvents.These changes result in different blocking effects,which,in turn,affect the adsorption behavior of metal treated activated carbons.X-ray diffraction (XRD) patterns of the samples treated with different metals are different each other.High intense sharp peaks attributed to metals are observed from silver treated samples,while the peaks are not observed from copper treated samples.To compare thermodynamic behavior of metal treated activated carbons washed with different type of solvents,differential scanning calorimetric (DSC) analysis is carried out.The analysis shows similar endothermic curves for all of the samples.Finally,antibacterial effects of metal treated activated carbon against Escherichia coli are discussed.Comparing the effects among the metals employed,highest effects are obtained from Cd,while lowest effects are obtained from Cu.Antibacterial activity becomes higher with the increase of the amount of metals treated,Optimum concentrations of metals to treat activated carbons,obtained from a shake flask test,are known to be 0.4,0.1,and 0.6 moles for Ag,Cd,and Cu,respectively.