Thesis Format
Integrated Article
Degree
Master of Science
Program
Chemistry
Abstract
The application of sodium chloride (NaCl) to maintain safe, passable transportation and infrastructure in Canada can adversely impact the environment, including salinization of freshwater resources and mobilization of heavy metals from soil, thereby motivating efforts to assess alternative salts. This thesis aims to provide a holistic overview of conventional and innovative de-icers, namely calcium chloride (CaCl2), magnesium chloride (MgCl2), potassium chloride (KCl), sodium acetate (NaOAc), calcium magnesium acetate (CMA), chloride free brine (CFB), and sugar brine (SB), for their ice melting efficacy and environmental impact. The ice-melting and ice-penetration ability of these alternative de-icers were examined in the laboratory following standardized procedures from the Strategic Highway Research Program (SHRP) test methods and in the field at a non-trafficked parking lot. A comprehensive suite of batch tests was performed to investigate the mobilization of 10 metals from a common roadside soil when exposed to various concentrations of each alternative de-icer. Results from this thesis showed that all de-icers experienced at least a 49% reduction in their ice-melting capacity when the temperature decreased from -6.7°C to -17.7°C. MgCl2 exhibited the highest ice-melting ability of all de-icers and was the only effective de-icer below -12.2°C. In terms of metal mobilization, the de-icers releasing the highest number of different metals (in decreasing order) were: (1) CaCl2 and SB, (2) KCl and MgCl2, (3) CMA, (4) NaCl, (5) CFB, and (6) NaOAc. The findings from this study can provide policy makers, municipalities, and other road salt users with more knowledge on the performance of alternative de-icers to allow them to make informed decisions on road salt application in Canada.
Summary for Lay Audience
The spreading of road salts can cause a range of environmental issues, with freshwater in streams, rivers, and lakes becoming more salty and various contaminants such as metals getting released from soils. These contaminants can end up in drinking water at levels that can affect human health. This is motivating people to develop and examine different road salts that are less harmful to the environment but can also melt snow and ice. The release of contaminants from soil can be examined using laboratory tests with the soil mixed with each de-icer and the resulting quality of water being measured. The ice-melting and ice-penetration ability of each road salt is investigated using procedures from standardized test methods in the laboratory and in the field to incorporate real site conditions. This thesis aims to investigate the ability of different road salts – sodium chloride (NaCl), calcium chloride (CaCl2), magnesium chloride (MgCl2), potassium chloride (KCl), sodium acetate (NaOAc), calcium magnesium acetate (CMA), chloride free brine (CFB), and sugar brine (SB) – to release metals from soils and to melt ice. The results from this study show that the ice-melting ability of each salt decreased by at least 49% when the temperature drops from -6.7 °C to -17.7 °C. In fact, most salts were unable to melt ice below -12.2°C, except MgCl2. The salts that release the most amount of metals (in decreasing order) were (1) CaCl2, SB, (2) KCl, MgCl2, (3) CMA, (4) NaCl, (5) CFB, and (6) NaOAc. Overall, this study provides more information on a variety of road salts so that road salt users, from municipalities to private contractors, can make better decisions and either apply less amounts of the harmful road salt or use an alternative salt that is more environmentally friendly.
Recommended Citation
Verkuil, Emily, "The ice melting efficacy and environmental impact of alternative de-icers" (2024). Electronic Thesis and Dissertation Repository. 10539.
https://ir.lib.uwo.ca/etd/10539
Included in
Environmental Chemistry Commons, Environmental Engineering Commons, Physical Chemistry Commons
