[Ex-situ remediation of PAHs contaminated site by successive methyl-beta-cyclodextrin enhanced soil washing].
Polycyclic aromatic hydrocarbon (PAH) polluted sites caused by abandoned coking plants have attracted great attentions. This study investigated the feasibility of using methyl-beta-cyclodextrin (MCD) solution to enhance ex situ soil washing for extracting PAHs. Treatment with elevated temperature (50 degrees C) in combination with ultrasonication (35 kHz, 30 min) at 100 g x L(-1) was effective. It was found that 96.7% +/- 2.4% of 3-ring PAH, 89.7% +/- 3.2% of 4-ring PAH, 76.3% +/- 2.2% of 5 (+6)-ring PAH and 91.3% +/- 3.1% of total PAHs were removed from soil after five successive washing cycles. The desorption kinetics of PAHs from contaminated soil was determined before and after successive washings. The 400 h Tenax extraction of PAHs from soil was decreasing gradually with increasing washing times. Furthermore, the F(r), F(sl), k(r), k(sl) and k(vl) were significantly lower than those of CK (P < 0.01). Therefore, considering the removal efficiency and potential environmental risk after soil )ashing, successive washing three times was selected as a reasonable parameter. These results have practical implications for site risk assessment and cleanup strategies.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. mmsun@issas.ac.cn
Ming-Ming
MM
Sun
Ying
Y
Teng
Yong-Ming
YM
Luo
Zhen-Gao
ZG
Li
Zhong-Jun
ZJ
Jia
Man-Yun
MY
Zhang
D001673:Biodegradation, Environmental / Q000187:drug effects; D002681:China; D003077:Coke; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007220:Industrial Waste / Q000517:prevention & control; D007221:Industry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000302:isolation & purification*; D012989:Soil Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D047392:beta-Cyclodextrins / Q000737:chemistry*
D003077:Coke; D007220:Industrial Waste; D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin