Microwave-enabled thermal remediation of organic chemical contaminated soils using dielectric nanomaterials as additives
View Patent ↗A soil remediation method for treating contaminated soil includes combining a dielectric carbonaceous nanomaterial with the contaminated soil to yield a composite contaminated soil, and irradiating the composite contaminated soil with microwave radiation to yield a remediated soil. The composite contaminated soil includes at least 1 wt % of the dielectric carbonaceous material, and the microwave radiation provides an energy input of at least 2.5 kWh per kilogram of the composite contaminated soil.
1. A soil remediation method for treating contaminated soil, the method comprising:
providing the contaminated soil to a conveyor belt proximate a microwave radiation source;
combining a dielectric carbonaceous nanomaterial with the contaminated soil to yield a composite contaminated soil, wherein the conveyor belt is fabricated to contain the dielectric carbonaceous nanomaterial, such that combining the dielectric carbonaceous nanomaterial with the contaminated soil comprises contacting the contaminated soil with the conveyor belt; and
irradiating the composite contaminated soil with microwave radiation to yield a remediated soil, wherein irradiating the composite contaminated soil with the microwave radiation occurs when the composite contaminated soil is on the conveyor belt, the composite contaminated soil comprises at least 1 wt % of the dielectric carbonaceous material, and the microwave radiation provides an energy input of at least 2.5 kWh per kilogram of the composite contaminated soil.
2. The soil remediation method of claim 1 , wherein the contaminated soil comprises at least 0.2 wt % of hydrocarbons having 12 to 40 carbon atoms.
3. The soil remediation method of claim 1 , wherein a water content of the contaminated soil is in a range of 20 wt % to 80 wt % of the water holding capacity of the soil.
4. The soil remediation method of claim 1 , wherein the composite contaminated soil comprises less than 10 wt % of the dielectric carbonaceous nanomaterial.
5. The soil remediation method of claim 1 , wherein the microwave radiation has a power in a range of 500-3000 W, a frequency in a range of 300 MHz to 300 GHz, or both.
6. The soil remediation method of claim 1 , wherein the microwave radiation provides an energy input of at least 5 kWh per kilogram of composite contaminated soil.
7. The soil remediation method of claim 1 , further comprising irradiating the composite contaminated soil with the microwave radiation for a length of time in a range of 1 second to 900 seconds.
8. The soil remediation method of claim 1 , wherein the remediated soil contains less than 2 wt % of hydrocarbons having 12 to 40 carbon atoms.
9. The soil remediation method of claim 1 , wherein irradiating the composite contaminated soil with the microwave radiation increases a temperature of the composite contaminated soil to at least 150° C.
10. The soil remediation method of claim 1 , wherein total petroleum hydrocarbon removal percentages in C12-C20, C20-C28, and C28-C36 carbon chain length fractions are at least 65%, at least 55%, or at least 35%, respectively.
11. The soil remediation method of claim 1 , wherein total petroleum hydrocarbon removal percentages in C12-C20, C20-C28, and C28-C36 carbon chain length fractions are up to 95%, 85%, and 75%, respectively.
12. The soil remediation method of claim 1 , wherein the dielectric carbonaceous nanomaterial comprises at least one of graphene, graphene oxide, carbon nanotubes, carbon nanofibers, and superfine powdered activated carbon.