US-20260125598-A1 - PLASTIC WASTE FOR FROST MITIGATION

Abstract

A mixture includes carbon-coated oil-treated plastic particles and particles that include geomaterial. Treating the soil at a building site includes combining carbon-coated oil-treated plastic particles and geomaterial particles to yield a mixture and providing the mixture in a built environment to enhance soil stability under freezing conditions.

Inventors

• Elham Fini
• Farideh Pahlavan
• Mohammadjavad Kazemi

Assignees

• Elham Fini
• Farideh Pahlavan
• Mohammadjavad Kazemi

Dates

Publication Date

20260507

Application Date

20251029

Claims (20)

1. 1 . A mixture comprising: carbon-coated oil-treated plastic particles; and particles comprising geomaterial.
2. 2 . The mixture of claim 1 , wherein the carbon-coated oil-treated plastic particles comprise polyethylene terephthalate particles coated with waste vegetable oil and biogenic carbon.
3. 3 . The mixture of claim 2 , wherein the biogenic carbon is derived from algal biomass.
4. 4 . The mixture of claim 1 , wherein the geomaterial comprises silt, soil, sand, or any combination thereof.
5. 5 . The mixture of claim 1 , wherein the carbon-coated oil-treated plastic particles lower the freezing point of the geomaterial.
6. 6 . The mixture of claim 1 , wherein the carbon-coated oil-treated plastic particles raise the thawing point of the geomaterial.
7. 7 . The mixture of claim 1 , wherein the carbon-coated oil-treated plastic particles suppress ice crystallization at a surface of the particles comprising geomaterial.
8. 8 . The mixture of claim 1 , wherein a particle size of the carbon-coated oil-treated plastic particles is in a range of 250 μm to 350 μm.
9. 9 . The mixture of claim 1 , wherein the mixture comprises 5 wt % to 75 wt % of the carbon-coated oil-treated plastic particles.
10. 10 . The mixture of claim 8 , wherein the mixture comprises 20 wt % to 50 wt % of the carbon-coated oil-treated plastic particles.
11. 11 . A method of treating the soil at a building site, the method comprising: combining carbon-coated oil-treated plastic particles and geomaterial particles to yield a mixture; and providing the mixture in a built environment to enhance soil stability under freezing conditions.
12. 12 . The method of claim 11 , wherein the carbon-coated oil-treated plastic particles comprise polyethylene terephthalate particles coated with waste vegetable oil and biogenic carbon.
13. 13 . The method of claim 12 , wherein the biogenic carbon is derived from algal biomass.
14. 14 . The method of claim 11 , wherein the geomaterial particles comprise silt, soil, sand, or any combination thereof.
15. 15 . The method of claim 11 , wherein a particle size of the carbon-coated oil-treat plastic particles is in a range of 250 μm to 350 μm.
16. 16 . The method of claim 11 , wherein combining the carbon-coated oil-treated plastic particles and geomaterial particles lowers the freezing point of the geomaterial in the geomaterial particles.
17. 17 . The method of claim 11 , wherein combining the carbon-coated oil-treated plastic particles and geomaterial particles raise the thawing point of geomaterial in the geomaterial particles.
18. 18 . The method of claim 11 , wherein combining the carbon-coated oil-treated plastic particles and geomaterial particles suppress ice crystallization at a surface of the geomaterial particles.
19. 19 . The method of claim 11 , wherein the mixture comprises 5 wt % to 75 wt % of the carbon-coated oil-treated plastic particles.
20. 20 . The method of claim 11 , wherein the mixture comprises 20 wt % to 50 wt % of the carbon-coated oil-treated plastic particles.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Patent Application No. 63/715,471 filed on Nov. 1, 2024, which is incorporated by reference herein in its entirety. STATEMENT OF GOVERNMENT SUPPORT This invention was made with government support under 1935723 awarded by the National Science Foundation. The government has certain rights in the invention. TECHNICAL FIELD This invention relates to carbon-coated, bio-grafted plastic granules for suppression of freezing in frost-susceptible soils. BACKGROUND In cold climates, phase changes of water-to-ice and ice-to-water in the pore structures of soils challenge the integrity and longevity of infrastructure. Soils in these regions undergo volumetric changes at least in part because of climatic stressors, impacting structures such as building foundations, bridges, pipelines, railways, dams, and pavement subgrades. SUMMARY This disclosure describes the use of waste plastic coated with biogenic carbon as a functional material for soils susceptible to frost heave and freeze-thaw. This bio-inspired approach draws inspiration from ice-binding proteins found in polar organisms, using principles of surface science to develop carbon-coated oil-treated plastic granules (C-OTPG) aimed at lowering the freezing point in frost-susceptible geomaterials. C-OTPG can effectively mimic the function of ice binding proteins by disrupting ice nucleation and crystal growth through interactions among C-OTPG's functional groups, water, and the siliceous substrate. This approach bolsters the resilience of geomaterials in cold climates while repurposing waste materials for sustainable applications. A Linkam Peltier LTS120 thermoelectrical cooling device and bright-field microscopy was used to measure freezing temperatures and thawing temperatures and to assess the ice-inhibition properties of both silt and fine sand treated with C-OTPG. For silt, C-OTPG treatment reduced the freezing point by up to 39% and increased thermal hysteresis by up to 65%, while for fine sand, the freezing point was reduced by up to 52% and thermal hysteresis increased by up to 38%. Calculations using density functional theory show strong hydrogen bonding and polar interactions between biogenic carbon and water molecules, preventing movement of water to the frost front and disrupting the formation of ice crystals. Additionally, biogenic carbon competes for adsorption sites on silica surfaces of sand and silt, while “capping” water molecules already on a silica surface inhibiting ice formation. In a first general aspect, a mixture includes carbon-coated oil-treated plastic particles and particles including geomaterial. Implementations of the first general aspect can include one or more of the following features. The carbon-coated oil-treated plastic particles can include polyethylene terephthalate particles coated with waste vegetable oil and biogenic carbon. The biogenic carbon can be derived from algal biomass. The geomaterial can include silt, soil, sand, or any combination thereof. The carbon-coated oil-treated plastic particles can lower the freezing point of the geomaterial. In some cases, the carbon-coated oil-treated plastic particles raise the thawing point of the geomaterial. In some implementations, the carbon-coated oil-treated plastic particles suppress ice crystallization at a surface of the particles including geomaterial. A particle size of the carbon-coated oil-treated plastic particles can be in a range of 250 μm to 350 μm. The mixture can include 5 wt % to 75 wt % of the carbon-coated oil-treated plastic particles. In certain cases, the mixture includes 20 wt % to 50 wt % of the carbon-coated oil-treated plastic particles. In a second general aspect, treating the soil at a building site includes combining carbon-coated oil-treated plastic particles and geomaterial particles to yield a mixture and providing the mixture in a built environment to enhance soil stability under freezing conditions. Implementations of the second general aspect can include one or more of the following features. The carbon-coated oil-treated plastic particles can include polyethylene terephthalate particles coated with waste vegetable oil and biogenic carbon. The biogenic carbon can be derived from algal biomass. The geomaterial particles can include silt, soil, sand, or any combination thereof. A particle size of the carbon-coated oil-treat plastic particles can be in a range of 250 μm to 350 μm. In some cases, combining the carbon-coated oil-treated plastic particles and geomaterial particles lowers the freezing point of the geomaterial in the geomaterial particles. In some implementations, combining the carbon-coated oil-treated plastic particles and geomaterial particles raise the thawing point of geomaterial in the geomaterial particles. Combining the carbon-coated oil-treated plastic particles and geomaterial particles can suppress ice crystallization at a surface of the geomateria