纳米Fe3O4覆盖对沉积物-水界面砷释放的影响

为揭示纳米四氧化三铁（nFe₃O₄）覆盖对沉积物溶解态砷（As）和有效态As的钝化效果，在开展室内培养试验的基础上，利用微界面分析技术、高分辨率平衡式间隙水采集技术（HR-peeper）和薄膜扩散梯度技术（DGT），探究nFe₃O₄覆盖下沉积物氧化还原环境、铁锰含量等因素对As的作用机制.结果表明：在nFe₃O₄覆盖下沉积物pH值较对照组逐渐增大，Eh先减小后增大；nFe₃O₄可以有效去除沉积物溶解态As，最大有效去除率为22%；nFe₃O₄覆盖使得有效态As的平均值降低了2.30mg/L；溶解态As与溶解态Fe （II）、溶解态As与溶解态Mn、有效态As与有效态Fe （II）、有效态As与有效态Mn均存在显著正相关关系（P<0.001）；nFe₃O₄的覆盖可以促进铁铝低结晶状无定形水合氧化态As含量的增加.

Effect of nFe3O4 capping on arsenic release at sediment-water interface

In order to reveal the passivation effect of nano-iron tetroxide (nFe₃O₄) covering on soluble arsenic (As) and labile As in sediments, on the basis of laboratory culture experiments, micro-interface analysis technology, high-resolution equilibrium gap Water harvesting technology (HR-peeper) and Diffusive Gradients in Thin-films technology (DGT) were used to explore the mechanism of action of As in the redox environment, iron and manganese content of sediments covered by nFe₃O₄. The results showed that the pH value of the sediment under the coverage of nFe₃O₄ gradually increased compared with the control group, and the Eh first decreased and then increased; nFe₃O₄ could effectively remove dissolved As from sediments, the maximum effective removal rate was 22%; the average value of available As was reduced by 2.30μg/L by the coverage of nFe₃O₄; There was a significant positive correlation between solube As, solube Fe(II) and solube Mn (P<0.001). Similarly, there was also a significant positive correlation between labile As, labile Fe(II) and labile Mn. (P<0.001); the coverage of nFe₃O₄ could promote the increase of the content of amorphous Fe and Al oxides bound.