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

Abstract

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 (C21–C30) 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 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 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 were consumed by organic matter and more OH 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 Ⅰ and protein II) and the active organic functional group (CO), while high content of inactive organic matter (fulvic acid, microorganism and humic acid) and inactive organic functional groups (CH and OH) was observed. Therefore, the allocation of OH was changed after SOM was inactivate, which result in less consumption of OH by SOM and efficiently dedicated oxidation of long-chain crude oil in the soil by inactive SOM-Fe.