Photo-assisted removal of fuel oil hydrocarbons from wood and concrete.
A novel photo-treatment to decontaminate building structural elements polluted with fuel oil hydrocarbons as a result of spillage and/or a catastrophic flood was examined. A proof-of-concept study evaluating the photocatalytic removal of hydrocarbons (n-hexadecane and fuel oil #2) from contaminated wood (southern yellow pine) and concrete was conducted using scintillation counting (with (14)C-labeled n-hexadecane) and gas chromatography. Contaminated samples were irradiated by UV or fluorescent light in the absence or presence of a photocatalyst, TiO(2). As a result of the treatment, under various scenarios, up to 80-98% of the originally applied n-hexadecane was removed, within a wide range of contaminant concentrations (4-250 mg/g wood). The essential treatment time increased from 1-7 days for low concentrations to several weeks for high concentrations. Mass balance experiments showed that the only product formed from (14)C-labeled n-hexadecane in detectable amounts was (14)CO(2). For low amounts of applied hydrocarbon (4-20 mg/g wood), the overall process rate was limited by the contaminant transport/mobility whereas for high n-hexadecane concentrations (150-250 mg/g, corresponding to 50-80% filling of wood pores), the key factor was the photochemical reaction. Photodegradation experiments conducted with standard heating fuel oil #2 (a representative real-world contaminant) resulted in a significant (up to 80%) photochemical removal of mid-size hydrocarbons (C(13)-C(17)) in 3 weeks whereas heavier hydrocarbons (> C(17)) were not affected; light hydrocarbons (< C(12)) were removed by evaporation. These results point toward a promising technique to reclaim wooden and concrete structures contaminated with semi-volatile chemicals.
Popova
Inna E
IE
Department of Chemistry, University of North Dakota, Grand Forks, North Dakota, USA.
Kozliak
Evguenii I
EI
D000473:Alkanes / Q000737:chemistry / Q000302:isolation & purification; D002384:Catalysis / Q000528:radiation effects; D002849:Chromatography, Gas; D003252:Construction Materials; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D006838:Hydrocarbons / Q000737:chemistry / Q000302:isolation & purification*; D008027:Light; D010777:Photochemistry / Q000379:methods; D015203:Reproducibility of Results; D014466:Ultraviolet Rays; D014934:Wood
D000473:Alkanes; D006838:Hydrocarbons; C007932:n-hexadecane