Next Article in Journal
Estimating Soil Organic Carbon in Agricultural Gypsiferous Soils by Diffuse Reflectance Spectroscopy
Previous Article in Journal
Quantitative Evaluation of Groundwater–Surface Water Interactions: Application of Cumulative Exchange Fluxes Method
Open AccessArticle

Longevity Aspects of Potable Water Disinfected by Ionic Silver: Kinetic Experiments and Modeling

1
Laboratory of Environmental Engineering & Planning, Department of Civil Engineering, Aristotle University of Thessaloniki, 54 124 Thessaloniki, Greece
2
Laboratory of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, 54 124 Thessaloniki, Greece
*
Authors to whom correspondence should be addressed.
Water 2020, 12(1), 258; https://doi.org/10.3390/w12010258 (registering DOI)
Received: 21 November 2019 / Revised: 7 January 2020 / Accepted: 14 January 2020 / Published: 16 January 2020
(This article belongs to the Section Water Quality and Ecosystems)
In the International Space Station (ISS), Russian and European cosmonauts drink water disinfected by dissolved silver. For this to be effective, the concentration of silver should remain above a certain threshold from the moment of its initial disposition in storage tanks on earth until its final consumption in ISS. Unfortunately, during water tanks transportation to ISS and during storage in ISS, silver concentration has been reported to decrease intensively beyond any reason. This work examines the effect of different materials used in ISS water storage and distribution systems on the reduction of silver concentration. An experimental campaign has been organized where passivated stainless steel (SS), passivated and electropolished SS and titanium alloy coupons (official ISS grades) are exposed to simulated ISS potable water at different silver concentrations, different surface to volume ratios, and at stagnant or flow conditions. The evolution of silver concentration remaining in the bulk water is recorded with respect to the exposure time. A reaction engineering model for the Ag loss to the coupons is developed. The model is fitted to the experimental data in order to derive the reaction rate expression and the corresponding parameters. For passivated SS and electropolished SS the silver deposition rate depends on the initial silver concentration in water but is rather unaffected by the progress of silver deposition on the surface. On the other hand, for Ti alloy, while silver deposition rate still depends on initial silver concentration, it decreases continuously as silver deposition on the surface advances, implying that Ti alloy surface becomes gradually saturated and so prevents further silver deposition. Such a model can be useful for material selection and design of water storage and distribution facilities for ISS. View Full-Text
Keywords: silver; potable water; disinfection; International Space Station; stainless steel; titanium alloy; kinetic modeling silver; potable water; disinfection; International Space Station; stainless steel; titanium alloy; kinetic modeling
Show Figures

Figure 1

MDPI and ACS Style

Petala, M.; Tsiridis, V.; Darakas, E.; Kostoglou, M. Longevity Aspects of Potable Water Disinfected by Ionic Silver: Kinetic Experiments and Modeling. Water 2020, 12, 258.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop