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Measurement and modelling of organophosphates leaching from concrete to water
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Peter Haglund)
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Organophosphate triesters used as additives in materials are leaching into the environment and have been found as pollutants in both water and sewage samples. Concrete is one of the most commonly used materials in the world and often contains tributyl phosphate (TBP) and triisobutyl phosphate (TiBP) as anti-foaming agents. In the present study, leaching of TBP and TiBP from concrete to water was measured over 16 weeks under laboratory conditions. The release was initially high (TBP 2900 ± 1060 10 μg/m2h; TiBP 8500 ± 800 μg/m2h), and then dropped to a low stable level over a six-week period. A generic model was developed to predict leaching of organic compounds to water. Three types of diffusion were modelled, dissolution from the surface, diffusion in cracks and pores, and diffusion in micro-pores in the concrete. The former type was assessed using the Nernst-Brunner dissolution and Fickian diffusion theory. The latter types required the use of three modules to model diffusion, solubilisation and 15 convective mass transfer processes separately. The boundary layer solubilisation was modelled using the Abraham solubility equation and solvation parameters taken from literature data. The results showed that the initial release of organophosphates from concrete to water can be significant (in some cases, >40% of the additive leaches out over the first few weeks) and that the long-term release of organophosphates from concrete constructions to the surrounding water can be accurately modelled. The model was applied to 20 estimate the release of TiBP to river water from the foundation of a bridge, resulting in a total loss of 2% of the additive over 8 years, with seasonal fluctuations in loss rate following changes in temperature and water flow. Due to the generic nature of the model, it can also be used to assess the leaching of other additives from concrete constructions to aquatic environments.

National Category
Chemical Sciences Materials Chemistry
URN: urn:nbn:se:umu:diva-66360OAI: diva2:606209
Available from: 2013-02-18 Created: 2013-02-18 Last updated: 2013-02-21Bibliographically approved
In thesis
1. Emissions of organic compounds from technosphere articles: Measurements and modeling of mass transfer from consumer goods and building materials to air and water
Open this publication in new window or tab >>Emissions of organic compounds from technosphere articles: Measurements and modeling of mass transfer from consumer goods and building materials to air and water
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis describes the development of a generic model for predicting the emissions of organic compounds from materials used in the manufacture of various goods and products. Many products contain organic substances that are not bound to the matrix formed by their constituent materials and are thus able to dissociate from the material and become transferred into the surrounding environment. A wide range of materials and products are used in modern societies, and many compounds deriving from these materials are regarded as emerging pollutants in both indoor and outdoor environments.

The model uses three components to describe the transfer of compounds from materials to the surrounding environment: partitioning of the compound between the material and its surroundings based on linear free energy relationships, diffusion within the material based on the Piringer equation, and convective mass transfer in air or water based on an empirical flat surface model. The model’s predictive capacity was tested against three experimental case studies: emissions of plasticizers from vinyl flooring and triphenyl phosphate from LCD screens into the air, and leaching of organophosphates from concrete into water. The rates of emission from vinyl flooring were clearly affected by the number of layers comprising the material. Triphenyl phosphate was found in the front surface of all tested flat screens and its rates of emission were related to the nature of the screen and its operating temperature. The model accurately predicted emissions into the air and leaching from concrete into water once modified to include modules that describe dissolution from surfaces and diffusion in water-filled pores.

The model was then used to investigate emissions on the national scale. It was found that the rates of emission from vinyl flooring are not changing over time, and that the total mass of emitted material is dependent on annual sales volumes and the expected life span of the vinyl flooring. Moreover, the additive used has a large effect on the emitted mass. Emissions from flat screen displays depend strongly on their operating temperatures: displays with high working temperatures that are active for extended periods of time produce more emissions. The model was also used to study the release of organophosphates from the concrete used to make a bridge, which depended on the flow of water under the bridge, the temperature, the porosity of the concrete, and the additive’s water solubility. Data on annual sales volumes and the total surface area of sold goods are essential when studying emissions on a national scale. National retailers’ organizations are valuable sources of such information. When adequate data are not available, it is necessary to perform uncertainty analyses to determine the impact of uncertainty in the modeling of different stages of the emissions process in different scenarios.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2013. 74 p.
Emission, model, DINP, DINCH, TiBP, TPP, Vinyl flooring, flat screen displays, LCD screen, concrete, Abraham solvation parameters, Piringer equation, linear free energy relation
National Category
Chemical Sciences
urn:nbn:se:umu:diva-66363 (URN)978-91-7459-562-8 (ISBN)
Public defence
2013-03-15, MIT-huset MA121, Umeå universitet, Umeå, 10:00 (English)
Available from: 2013-02-22 Created: 2013-02-18 Last updated: 2013-02-22Bibliographically approved

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