纳米Fe_(3)O_(4)覆盖对沉积物水界面钴和镍的吸附试验研究

Study on the adsorption of cobalt and nickel at the sediment-water interface by nano-Fe_(3)O_(4) overlay

为揭示纳米材料原位覆盖对表层沉积物重金属的影响规律,开展室内培养原位沉积物柱试验,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),探究纳米Fe_(3)O_(4)原位覆盖对表层沉积物中Co、Ni释放的影响机制。试验结果表明:在纳米Fe_(3)O_(4)覆盖下沉积物pH值较对照组逐渐增大,Eh值先减小后增大;纳米Fe_(3)O_(4)覆盖可有效吸附间隙水中的溶解态Co和Ni,间隙水中的溶解态Co和Ni最大有效吸附率分别为27.07%及26.42%,有效影响深度分别为30 mm和10 mm;纳米Fe_(3)O_(4)覆盖有效抑制了沉积物中有效态Co和Ni向间隙水和上覆水扩散,沉积物中有效态Co和Ni含量分别降低了50.26%和15.31%。

To reveal the effect of in-situ coverage of nano materials on heavy metals in surface sediments,the incubation experiments of in-situ sediment columns were carried out.Using micro-interface analysis technique,the high-resolution dialysis(HR-Peeper)technique and the diffusive gradients in thin films(DGT),the influence mechanisms of in-situ coverage of Fe_(3)O_(4) nanoparticles on the release of Co and Ni from surface sediments were dissected.The results shows that the pH of the sediment covered by the nano-Fe_(3)O_(4) gradually increased compared to that of the control group,while the Eh value decreased first and then increased.The coverage of nano-Fe_(3)O_(4) can effectively adsorb the dissolved Co and the dissolved Ni in the pore water,and the maximum effective adsorption rates of dissolved Co and dissolved Ni in the pore water were 27.07%and 26.42%,respectively,with effective effect depths of 30 mm and 10 mm,respectively.The coverage of nano-Fe_(3)O_(4) effectively inhibit the diffusion of labile Co/Ni in sediments to overlying water and reduced the content of labile Co/Ni in sediments by 50.26%and 15.31%,respectively.