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Iron bound to soil organic matter catalyzes H2O2 to oxidize crude oil in soil

Author:
Xu, Jinlan, Fan, Xinshuo, Huang, Fudi, Li, Xiumin
Source:
Journal of hazardous materials 2017 v.322 pp. 516-524
ISSN:
0304-3894
Subject:
alkanes, catalytic activity, hydrogen peroxide, hydrophobicity, hydroxyl radicals, iron, iron oxides, petroleum, polluted soils, soil organic matter, soil sampling
Abstract:
Under the action of hydrogen peroxide, soil organic matter (SOM) can transform dissolved iron (Fe²⁺) into the solid phase. Solid iron is bound to SOM (Fe-SOM), and two components are included: iron oxides bound to SOM (Fe-SOM oxides) and organic iron bound to SOM (organic Fe-SOM). In oil-contaminated soil samples with Fe-SOM, total petroleum hydrocarbon (TPH) was degraded by 67%; however, in oil-contaminated soil samples without Fe-SOM, the degradation of TPH was only 6%. In oil-contaminated soil samples with Fe-SOM, 73–86% of the primary alkanes (C14-C22 composed 67.5% of TPH) were removed, whereas only 45–65% of the C12-C13 and C22-C30 alkanes were removed. The 11 types of alkanes (C12-C13 and C22-C30) accounted for only 32.5% of TPH. Obviously, the degradation of TPH by Fe-SOM is independent of its hydrophobicity in the solid phase. The results also demonstrated that at a higher content of Fe-SOM, more hydroxyl radical (OH) was produced in the solid phase and more TPH was degraded. A large number of OH are generated near iron-SOM-oil interface.
Agid:
6107021