Comparison of the efficiency of natural and synthetic zeolites modified with cationic surfactants as a disinfectant against Escherichia coli, Enterobacter, and Enterococcus

摘要

The aim of this study was to compare the efficiency of modified zeolite with two cationic surfactants as a disinfectant against Escherichia coli, Enterobacter, and Enterococcus. Natural and synthetic zeolites were modified by cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride by the impregnation method. For modification of zeolites, surfactants were used equal to 0.5, 1.0, and 2.0 ECEC of each zeolite. The examined bacteria were isolated from polluted water. Bacteriological examinations were conducted by microbroth dilution and agar disc diffusion (Kirby-Bauer) methods. The results showed that Gram-positive bacteria are more sensitive than Gram-negative bacteria. Additionally, the antibacterial activity of modified natural zeolite was better than synthetic zeolite (p = 0.02). Also, significant differences between the inhibition zone of natural zeolite and synthetic zeolite values with parent zeolite were observed (p = 0.003 and p = 0.018, respectively). Enterococcus and Enterobacter show the highest efficiency for CTAB-natural zeolite with an inhibition zone diameter of 15 +/- 3.6 and 9.33 +/- 8.08 mm, respectively. The microbroth dilution test showed that Gram-negative bacteria are resistant against modified natural zeolite and modified synthetic zeolite with cell density of 1.5 x 10(8) CFU/mL and = 3 x 10(8) CFU/mL, respectively, while Gram-positive bacteria show nearly 0 cell density. It is concluded that modified zeolites could have effect on water indicator bacteria.