间歇搅拌对沼渣协同硫酸亚铁修复含铬土壤的影响

Investigation on the mechanism of intermittent stirring on the remediation of chromium-containing soil by digestate coupled with ferrous sulfate

采用间歇搅拌强化沼渣协同硫酸亚铁修复法,首先对间歇搅拌与静置堆放处理下沼渣协同硫酸亚铁修复含铬土壤的效果进行了对比分析,随后采用XPS对过程中Cr、S、Fe、的形态进行分析,最后结合微生物群落测试,综合对相关机制进行阐述.结果表明,相比较静置堆放,间歇搅拌可大大加快反应速率,最快可在2d内将含铬土壤Cr(Ⅵ)浓度从3000mg/kg降低至未检出.间歇搅拌体系内SO_(4)^(2-)还原速率显著高于静置堆放体系,且体系内S^(2-)比例上升.微生物群落分析表明,间歇搅拌提高了土壤样品内具有Cr(Ⅵ)耐受性的菌种的活性,间歇搅拌土壤内铬还原菌、硫酸盐还原菌的相对丰度较高.本研究证明了间歇搅拌作用强化了Cr(Ⅵ)还原效率、促进了硫酸盐还原、改善了微生物群落结构.

The effect of intermittent stirring on the remediation of Cr(Ⅵ)-containing soil via digestate coupled with ferrous sulfate was investigated.Speciation changes of chromium(Cr),sulfur(S)and iron(Fe),during the process were examined through X-ray Photoelectron Spectroscopy(XPS).Finally,complemented by microbial community analysis,the mechanism was elucidated.The results indicated that intermittent stirring significantly accelerated the reaction compared to static incubation.Non-detectable Cr(Ⅵ)in soil with initial Cr(Ⅵ)content of 3000mg/kg could be achieved within 2 days.The sulfate reduction was higher under intermittent stirring,accompanied with an increase of S^(2-)content.Microbial community analysis showed that Cr(Ⅵ)-tolerant bacteria was activated after intermittent stirring treatment with a higher relative abundance of chromium-reducing and sulfate-reducing bacteria.Overall,intermittent stirring enhances Cr(Ⅵ)reduction efficiency,promoted sulfate reduction,and positively impacts microbial community structure,offering a promising approach for the low-carbon and efficient treatment of Cr(Ⅵ)-contaminated sites.