Efficiently dedicated oxidation of long-chain crude oil in the soil by inactive SOM-Fe

To find out the mechanism of efficiently dedicated oxidation of long-chain crude oil in the Fenton system with inactive SOM-Fe, two crude oil-contaminated soils with different concentrations (S1: 14579 mg/kg; S2: 15491 mg/kg) were used as the treatment targets in this study. The results showed that the removal of long-chain crude oil (C-21-C-30) with inactive SOM-Fe (3120-6930 mg/kg) was much higher than that with active SOM-Fe (2493-4424 mg/kg). Moreover, about 62%-71% (OH)-O-center dot was allocated for direct oxidation of long-chain crude oil with inactive SOM-Fe compared to that with active SOM-Fe. Meanwhile, the highest removal of long-chain crude oil by unit (OH)-O-center dot yield was 1345 mg/kg for inactive SOM-Fe, which was 3.6 times that for active SOM-Fe. It can be seen that less (OH)-O-center dot were consumed by organic matter and more (OH)-O-center dot was allocated to dedicatedly oxidize long-chain crude oil in inactive SOM-Fe Fenton system. Further analysis found that, for inactive SOM-Fe the low content of active organic matter (protein. and protein II) and the active organic functional group (C=O), while high content of inactive organic matter (fulvic acid, microorganism and humic acid) and inactive organic functional groups (C-H and O-H) was observed. Therefore, the allocation of (OH)-O-center dot was changed after SOM was inactivate, which result in less consumption of (OH)-O-center dot by SOM and efficiently dedicated oxidation of long-chain crude oil in the soil by inactive SOM-Fe.