Silver supported on natural Mexican zeolite as an antibacterial material

The antimicrobial effect of the Mexican zeolitic mineral from Taxco, Guerre ro exchanged with silver ions was investigated. The zeolitic mineral as wel l as sodium and silver zeolitic minerals were characterized by using X-ray diffraction, electron microscopy and IR spectroscopy techniques. The elemen tary composition of the zeolitic mineral was determined by atomic absorptio n and microanalyses (EDAX), Escherichia coli and Streptococcus faecalis as indicators of fecal contamination of water were chosen to achieve the antib acterial effect of the Mexican silver zeolitic mineral. The amount of silve r in water after contact with the Mexican silver zeolitic mineral as a func tion of both time and initial sodium concentration in liquid media using Ag -110m and Na-22 as radiotracers was analyzed. It was found that the Mexican silver clinoptilolite-heulandite mineral eliminated the pathogenic microor ganisms E. coli and S. faecalis from water with the highest amount of silve r supported on the mineral after 2 h of contact time. Under these condition s, the silver level in water remained in 50 mu g1(-1) (NOM-041-SSA1-1993). (C) 2000 Elsevier Science B.V. All rights reserved.