Main content area

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

Xu, Jinlan, Fan, Xinshuo, Huang, Fudi, Li, Xiumin
Journal of hazardous materials 2017 v.322 pp. 516-524
alkanes, catalytic activity, hydrogen peroxide, hydrophobicity, hydroxyl radicals, iron, iron oxides, petroleum, polluted soils, soil organic matter, soil sampling
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.