Carbonaceous nano-additives augment microwave-enabled thermal remediation of soils containing petroleum hydrocarbonsf

摘要

Remediating soils contaminated with heavy hydrocarbons (C12-C40) from petrochemical exploration activities is a major environmental challenge across the globe. This study evaluated microwave irradiation in the presence of nano-and macro-scale graphitic additives as a rapid remediation technology for removing heavy hydrocarbons from soil. Adding inert materials (;'.e., glass wool fibers or washed silica sand) as controls had no effect on total petroleum hydrocarbons (TPH) removal upon microwave irradiation. Carbonaceous nanomaterials (;'.e., carbon nanotubes, graphene nanosheets, and carbon nanofibers) because of their favorable dielectric properties showed extraordinary heating performances when mixed with soil and microwave irradiated. As a result, adding these carbonaceous nanomaterials to contaminated soils removed more TPH compared with macro-scale carbonaceous additives. TPH concentrations decreased from 11000 to between 2000 and 6000 mg TPH kg~(-1) soil within one minute using carbon nanomaterial additives and a 2.45 GHz, 1000 W conventional microwave oven. In separate experiments, this technology decreased TPH from 2500 to 650 mg TPH kg"1 soil from soils containing recalcitrant, non-biodegradable fractions of TPH. Large scale microwave systems are available and hold promise for remediating soils when used in conjunction with carbon nanomaterials.