Silver supported on natural Mexican zeolite as an antibacterial material

The antimicrobial effect of the Mexican zeolitic mineral from Taxco, Guerrero exchanged with silver ions was investigated. The zeolitic mineral as well as sodium and silver zeolitic minerals were characterized by using X-ray diffraction, electron microscopy and IR spectroscopy techniques. The elementary composition of the zeolitic mineral was determined by atomic absorption and microanalyses (EDAX), Escherichia coli and Streptococcus faecalis as indicators of fecal contamination of water were chosen to achieve the antibacterial effect of the Mexican silver zeolitic mineral. The amount of silver in water after contact with the Mexican silver zeolitic mineral as a function 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 microorganisms E. coli and S. faecalis from water with the highest amount of silver supported on the mineral after 2 h of contact time. Under these conditions, the silver level in water remained in 50 mu g1(-1) (NOM-041-SSA1-1993). (C) 2000 Elsevier Science B.V. All rights reserved.