The Use of Sustained Release Technology to Reduce Deicing Salt Pollution

Abstract

The freshwater in North America are becoming increasingly saline due to the excessive production and use of salt, with road deicing salt being a major contributor. Every winter, an astonishing twenty million tons of road salt are applied to public roads in the U.S. for deicing, accounting for over 41% of the nation's total salt consumption. As these salts dissolve, they flow into streams, rivers, and lakes, posing severe threats to the environment, ecosystems, and infrastructure. This research aims to address this issue by reducing reliance on chloride-based deicers and developing a more environmentally friendly deicing system. To achieve this, we designed a core-shell structured capsule that enables the controlled and sustained release of deicing agents precisely when and where needed, and in the required amounts. The core-shell structures allow for the combination of natural deicers, such as beetroot juice, with chloride deicers in a unique manner. Beetroot is encapsulated within a NaCl particle-walled vessel using a rolling coating process, reinforced with a barrier layer. When the capsule is applied onto icy roads and subjected to external compression (e.g., road traffic), the beet juice stored in the beetroot core is released, partially dissolving the sodium chloride to form a synergistic deicing composition. The structure of the core-shell prototypes was characterized, and their deicing performance was tested. Preliminary data indicates that the method developed in this research effectively de-ices and can reduce salt usage by 35% under mild winter road conditions, offering a more eco-friendly and cost-effective deicing solution.