Researchers at Washington State University (WSU) (Pullman, Washington, USA) are working to develop a less corrosive alternative to traditional deicers by utilizing grape skins and other agricultural waste.
Led by Xianming Shi, an associate civil and environmental engineering professor at the school and graduate student Mehdi Honarvar Nazari, the researchers determined that their deicer containing grape extract outperformed commonly used deicers, such as road salt and what is believed to be a more environmentally friendly blend of salt brine and beet juice.
Limitations of Traditional Deicers
According to school estimates,1 the United States spends approximately $5 billion each year to repair damages to road infrastructure from winter snow, ice control operations, and the use of traditional deicers. Their estimates show that roughly 27 million tons of sodium chloride (NaCl), commonly known as road salt, is used on U.S. roadways each year for winter maintenance.
The chlorides do not degrade in the environment and may pose long-term environmental risks, according to the researchers. That’s because commercial deicers typically contain chemicals that are corrosive toward metals, asphalt, concrete, and pose some risk to aquatic species.
In response, beet juice has become a common additive used by highway departments and cities to enhance the performance of deicers while reducing their corrosive impacts. However, when beet juice enters water bodies, it can deplete oxygen and endanger aquatic organisms, according to the research team.
Developing a Greener Additive
Thus, the researchers wanted to maintain the benefits of reduced corrosion while further improving the environmental impact. Working to develop a greener additive, the WSU researchers derived chemicals from waste grape skins through chemical degradation and natural fermentation. Shi says their novel process to make the formula produces no waste of any kind.
The researchers found that their grape extract-based solution melts ice faster than other deicers and causes significantly less damage to concrete and asphalt, the two most ubiquitous materials used in bridges and roads. The solution also poses less risk to nearby water bodies.
“We delivered a more sustainable solution because we’re introducing less chlorides into the road operations and are achieving comparable or better performance,” Shi says. “It’s one step in the right direction.”
Research Background
Shi says he first thought of using biotechnology to derive deicer additives out of agricultural waste materials several years ago when tasked by the Alaska Department of Transportation (Juneau, Alaska, USA) to develop locally sourced and performance-enhanced brine formulations for anti-icing.
His group has also successfully applied this technology to waste peony leaves, sugar beet leaves, dandelion leaves, and waste from apples and grapes.
“The beauty of this approach is that it allows us to diversify,” Shi says. “We can use this same platform technology in different regions of the country but choose a different agricultural product, depending on what source of waste is available.”
The work was supported by the U.S. National Science Foundation (Alexandria, Virginia, USA), the Washington Department of Transportation (Olympia, Washington, USA), and the U.S. Department of Transportation (Washington, DC, USA). Further details are available in a recent technical article published in the December 2019 issue of the Journal of Materials in Civil Engineering.2
Source: Washington State University, news.wsu.edu.
References
1 “Sustaining Roads with Grape and Agricultural Waste,” WSU Insider Science & Technology, Dec. 2, 2019, https://news.wsu.edu/2019/12/02/sustaining-roads-grape-agricultural-waste/ (Dec. 10, 2019).
2 M.H. Nazari, X. Shi, “Developing Renewable Agro-Based Anti-Icers for Sustainable Winter Road Maintenance Operations,” Journal of Materials in Civil Engineering 31, 12 (2019).