Rapid degradation of long-alkanes by mild Fe-SOM pre-oxidation in soils

• Published in: Journal of environmental management 2023-09, Vol.342, p.118291-118291, Article 118291
• Main Authors: Xu, Jinlan, Gong, Lixia, Cao, Zezhuang, Xu, Kaihui, Xue, Shujun, Shu, Qilin
• Format: Article
• Language: English
• Subjects: Alkanes; Bacteria - metabolism; Biodegradation; Biodegradation, Environmental; Degree of bacterial kill; Fast degradation; Hydrocarbons; Long-alkanes; Mild Fe-SOM pre-Oxidation; Oil-contaminated soils; Petroleum; Soil; Soil Pollutants - analysis
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2023.118291

In this study, a novel mild pre-oxidation mode was successfully explored by fabricating Fe-SOM prepared by adding 2.5% and 20% fulvic acid (FA). This study explored the mechanism of mild Fe-SOM pre-oxidation to stimulate rapid biological degradation of long-alkanes in oil-contaminated soils. Results showed that under mild Fe-SOM pre-oxidation, the total •OH intensity and bacterial killing degree（D） were low, and hydrocarbon conversion（C）was fast, resulting in rapid degradation of long-alkanes. Additionally, the fast group removed 1.7-fold more than slow group and biodegraded long-alkanes 182 days significantly faster. Furthermore, compared with slow group (8.26 log CFU/g), the fast group (51.48 log CFU/g) characterized much more bacteria. Besides, the fast group had higher C (5.72%–15.95%), thus increasing the degradation rate of long-alkanes (7.61%–18.86%). A shift in the microbial community was found after mild Fe-SOM pre-oxidation, with an average relative abundance of 18.6% for the dominant genus Bacillus. Therefore, the mild pre-oxidation reduced the D, and the high bacterial abundance promoted nutrients consumption and C, which shortened bioremediation period and increased the long-alkanes degradation rate. This study provided a promising novel mild Fenton pre-oxidation mode to rapid remediate heavily multicomponent oil-contaminated soils. [Display omitted] •The low .•OH intensity and bacterial killing degree were achieved by mild Fe-SOM pre-oxidation.•Crude oil was easily adsorbed due to hydrophobic Fe-SOM with high proportion of FA-like.•Fast group showed a 1.7-fold higher removal of TPHs and 182 days of long-alkanes saved.•Bacillus was the main genus for degrading TPHs.