【摘要】 采用自制的绿色合成纳米零价铁铜(GT-nZVI/Cu)对Cr(Ⅵ)污染土壤进行淋洗修复。分别测定了土壤浸出液中Cr(Ⅵ)浓度、pH值和电导率,并使用改进的BCR连续提取法分析了淋洗前后污染土壤中铬的形态变化。结果表明:淋洗过程分为2个阶段,Cr(Ⅵ)的释放主要在前3个孔隙体积(PV)内;浸出液中电导率的变化趋势与Cr(Ⅵ)浓度变化一致;浸出液pH值随着淋洗体积的增加而增加,土壤的平衡作用变得稳定;土壤中Cr(Ⅵ)浓度、悬浮液pH值和GT-nZVI/Cu浓度对铬污染土壤的修复效果均有一定影响。铬的形态分析表明:铬污染土壤在淋洗后可还原态铬含量降低,氧化态铬和残渣态铬的含量增加。GT-nZVI/Cu悬浮液对污染土壤淋洗后,土壤中铬形态更加稳定。更多还原

【Abstract】 In this study,stable suspensions of green synthesized nanoscale zero-valent iron/copper( GT-nZVI/Cu) were prepared to leach and remediate the soil contaminated by hexavalent chromium( Cr( Ⅵ)). The Cr( Ⅵ) concentration,pH value and electrical conductivity of leachate from soil were measured,and then,morphological change of chromium in Cr( Ⅵ)contaminated soil before and after leaching was analyzed by using the modified BCR sequential extraction method. Results showed that there were two stages in the leaching process,and the release of Cr( Ⅵ) was mainly in the first three pore volume( PV); the change trend of electrical conductivity of leachate was consistent with change trend of Cr( Ⅵ) concentration; the pH values of the leachate increased with the increase of PV,and the balancing action of the soil became stable; Cr( Ⅵ)concentration in the soil,pH value of suspension and GT-nZVI/Cu concentration had a certain influence on the remediation effectiveness of Cr( Ⅵ) contaminated soil,and the effect of Cr( Ⅵ) concentration in the soil was the most obvious.Morphological analysis of chromium revealed that reducible chromium decreased,while oxidizable and residual chromium increased after leaching the Cr( Ⅵ) contaminated soil. GT-n ZVI/Cu suspensions made the chromium in contaminated soil more stable after leaching.更多还原