A soil-column gas chromatography (SCGC) approach to explore the thermal desorption behavior of hydrocarbons from soils.
A soil-column gas chromatography approach was developed to simulate the mass transfer process of hydrocarbons between gas and soil during thermally enhanced soil vapor extraction (T-SVE). Four kinds of hydrocarbons-methylbenzene, n-hexane, n-decane, and n-tetradecane-were flowed by nitrogen gas. The retention factor k' and the tailing factor T f were calculated to reflect the desorption velocities of fast and slow desorption fractions, respectively. The results clearly indicated two different mechanisms on the thermal desorption behaviors of fast and slow desorption fractions. The desorption velocity of fast desorption fraction was an exponential function of the reciprocal of soil absolute temperature and inversely correlated with hydrocarbon's boiling point, whereas the desorption velocity of slow desorption fraction was an inverse proportional function of soil absolute temperature, and inversely proportional to the log K OW value of the hydrocarbons. The higher activation energy of adsorption was found on loamy soil with higher organic content. The increase of carrier gas flow rate led to a reduction in the apparent activation energy of adsorption of slow desorption fraction, and thus desorption efficiency was significantly enhanced. The obtained results are of practical interest for the design of high-efficiency T-SVE system and may be used to predict the remediation time.
College of Environmental Science and Engineering, Dalian Maritime University, Ling Hai Road 1, Dalian, 116026, China. yyuhelen@dlmu.edu.cn.
Ying
Y
Yu
College of Environmental Science and Engineering, Dalian Maritime University, Ling Hai Road 1, Dalian, 116026, China.
Liang
L
Liu
College of Environmental Science and Engineering, Dalian Maritime University, Ling Hai Road 1, Dalian, 116026, China.
Ziying
Z
Shao
College of Environmental Science and Engineering, Dalian Maritime University, Ling Hai Road 1, Dalian, 116026, China.
Tianyu
T
Ju
College of Environmental Science and Engineering, Dalian Maritime University, Ling Hai Road 1, Dalian, 116026, China.
Bing
B
Sun
Laboratoire de Génie Civil et d'Ingénierie Environnementale, INSA-Lyon, Bâtiment Sadi Carnot 20, Avenue Albert Einstein, 69621, Villeurbanne Cedex, France.
Belkacem
B
Benadda
D000327:Adsorption; D000473:Alkanes / Q000737:chemistry; D002849:Chromatography, Gas / Q000379:methods*; D006586:Hexanes / Q000737:chemistry; D006838:Hydrocarbons / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013696:Temperature; D014050:Toluene / Q000032:analysis
D000473:Alkanes; D006586:Hexanes; D006838:Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; C024713:n-tetradecane; C026385:n-hexane; D014050:Toluene
Hydrocarbon contamination; Soil remediation; Thermal desorption; Thermally enhanced SVE