Silver-modified clinoptilolite-heulandite-rich tuff as microbicide agent in a column system for specific microorganisms and consortium from a deionized water suspension

• Published in: Desalination and water treatment 2018-08, Vol.123, p.109-118
• Main Authors: Gonzaga-Galeana, V.E., De-La-Rosa-Gómez, I., Olguin, M.T.
• Format: Article
• Language: English
• Subjects: Continuous system; Disinfection; Microbial consortium; Silver-modified-clinoptilolite-heulandite
• ISSN: 1944-3986
• DOI: 10.5004/dwt.2018.22780

The pathogen microorganism found in water causes several diseases in the human being and it is essential finding alternatives for water disinfection especially for regions which not count with purified water distribution systems. The natural zeolites modified with metals have been investigated for this purpose. However, few works have been considered a consortium of microorganisms and packed column systems. Therefore, the microbicide effect of silver-modified clinoptilolite- heulandite-rich tuff (ZGAg) on a specific microorganisms or microorganism consortium composed by Escherichia coli, Staphylococcus aureus, and Candida albicans in a continuous system was investigated considering the characteristics of each microorganism, the complexity of microorganism systems (individual species or consortium), and the height of the natural zeolite bed (mass of the microbicide agent). The release of silver from the silver-modified clinoptilolite-heulandite-rich tuff after the disinfection processes in the continuous system was also considered in this work. The natural zeolite of 30 mesh particle size from Guerrero (Mexico) was modified with silver using an AgNO3 solution. Unmodified and silver-modified natural zeolites were characterized by scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray diffraction. Microbial cultures from the American Type Culture Collection were acquired for the disinfection experiments. The obtained disinfection breakthrough curves were analyzed to obtain different parameters (among them breakpoint, disinfected water volume, and disinfection process kinetics). It was found that the disinfected water volume was higher for E. coli than S. aureus and C. albicans for both 300 and 400 mg of ZGAg and the volume varied depending on the mass of the microbicide zeolitic material. The resistance of the microorganism to the microbicide zeolitic material was changed when the microorganisms are in a consortium. The disinfection experimental data were well fitted to a nonlinear logistic model and the mass of the ZGAg and the type of microorganism affect the t50 and k parameters.