纳米Fe3O4对红壤微生物数量、酶活性及2,4-D降解的影响

 【目的】从磁致效应的角度考察纳米四氧化三铁(Fe3O4)对红壤微生物数量和酶活性的影响,研究纳米Fe3O4处理对红壤中2,4-D的降解效果,为纳米磁处理技术用于污染土壤修复提供依据。【方法】采用不同剂量的纳米Fe3O4处理红壤,用稀释平板法和化学比色法测定处理前后微生物数量和酶活性的变化;利用高效液相色谱(HPLC)测定土壤中2,4-D浓度的变化。【结果】纳米Fe3O4对细菌和放线菌有激活效应,但对真菌存在抑制作用,且当纳米Fe3O4投加量为80 g•kg-1时磁致效应最显著;同样,纳米Fe3O4对淀粉酶、脲酶、中性磷酸酶和过氧化氢酶也具有激活效应,但对不同酶活性的影响程度存在差异;经纳米Fe3O4处理后红壤中2,4-D的降解率明显高于未处理组,7 d内2,4-D的降解率可达84%。【结论】纳米Fe3O4处理后红壤中的微生物数量和酶活性显著增加,且红壤对2,4-D的降解能力明显增强。

Effects of Nanoscale Fe3O4 on Microbial Communities, Enzyme Activities and 2,4-D Degradation in Red Soil

【Objective】The effects of magnetic field on microbial communities and enzyme activities in red soil by nanoscale Fe3O4 were investigated, and the degradation of herbicide 2,4-D in red soil after nanoscale Fe3O4 treatment was also studied. The research will provide a basis for soil remediation by magnetic nanoparticles treatment. 【Method】 The red soil was treated by different dosages of nanoscale Fe3O4, then the microbial communities and enzyme activities were analyzed by dilution plate method and chemical assay, and the concentration of 2,4-D in soil was determined by high performance liquid chromatography (HPLC). 【Result】 The results indicated that the nanoscale Fe3O4 treatment had a positive effect on bacteria and actinomycetes, however, the fungi number was decreased by the same treatment. The effects of magnetic field on microbial communities increased with the dosage of nanoscale Fe3O4, and the microbial number reached the maximum at the dosage of 80 g•kg-1. Similarly, the nanoscale Fe3O4 could also improve the activities of amylase, urease, neutral phosphatase and catalase, but the effects of magnetic field on enzyme activities were different. The degradation rate of 2,4-D in red soil treated with the nanoscale Fe3O4 was significantly higher than that without treatment, and the 84% of 2,4-D could be degraded in 7 days.【Conclusion】The nanoscale Fe3O4 can improve the microbial communities and enzyme activities as well as the degradation of 2,4-D in red soil.