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Alkali-Activated Foams Coated with Colloidal Ag for Point-of-Use Water Disinfection
journal contributionposted on 2024-01-20, 14:09 authored by Mohammad Amzad Hossain Bhuyan, Antti Karkman, Hanna Prokkola, Boyu Chen, Priyadharshini Perumal, Tero Luukkonen
Alkali-activated foams are ceramic-like materials prepared at near-ambient temperature. This study investigates them for point-of-use water disinfection, thus providing an alternative to ceramic filters fired at a high temperature. Alkali-activated foams with different compositions were characterized for the porosity, mechanical strength, shrinkage, and microstructure. The optimized foam, employing metakaolin as the raw material, was coated with a colloidal Ag solution. The disinfection performance and leaching behavior of the foams was followed in a continuous 10 week experiment, where clean water with a weekly pulse of contaminated water was distributed through the foam. The average inactivation of Escherichia coli with the Ag-coated foam was 2.84 log10, which was 1.27 units higher compared to foam without Ag. A quantitative polymerase chain reaction analysis and metagenomic sequencing verified that foams with and without Ag were both capable of reducing the microbial load. Furthermore, the changes induced by the foam with Ag on the microbial community composition, antibiotic resistome, and metal and biocide resistomes were significant. The leached concentrations of Ag, Na, Si, and Al were in accordance with the drinking water guidelines. Finally, a life cycle assessment indicated the possibility of reducing the global warming potential and the total embodied energy in comparison with a conventional ceramic filter.
total embodied energymetagenomic sequencing verifiedlike materials preparedglobal warming potentialmicrobial community compositiondrinking water guidelinesconventional ceramic filterceramic filters fireduse water disinfectioncolloidal ag solutionfoam without agactivated foams coatedwithout agcolloidal agmicrobial loaddisinfection performancecontaminated waterclean wateractivated foamsweekly pulsethus providingstudy investigatesraw materialoptimized foammechanical strengthleaching behaviorleached concentrationshigh temperatureescherichia coliemploying metakaolindifferent compositionscoated foamchanges inducedbiocide resistomesaverage inactivationantibiotic resistomeambient temperature84 log