Abstract We synthesized nanoscale FeII-AlIII layered double hydroxide (LDH) and investigated its efficiency for reductive immobilization of Cr(VI) in a Cr-spiked alkaline loam soil using both batch and column experiments. Results of batch experiments indicated that addition of fresh LDH suspension to the soil at a mole ratio of Cr(VI) to structural FeII in LDH [FeII(s)] = 0.2, completely immobilized Cr(VI). Column experiments, using same Cr(VI)/FeII(s) ratio, were conducted under four various modes of LDH suspension application to the soil. Addition of LDH suspension to the saturated and unsaturated packed soil columns at a pressure head of 2 cm was inefficient in reducing Cr(VI) to Cr(III) because of shallow penetration of LDH particles into the soil. Injection of LDH suspension into the soil columns greatly improved penetration of LDH particles into the soil. However, only 18.8% of leachable Cr(VI) was immobilized in the saturated soil column, while the same operation in the unsaturated column experiment increased Cr(VI) immobilization efficiency to 70.0%, a significant improvement in immobilization. In summary, nanoscale FeII-AlIII LDH was shown to be a fast and strong reductant, which successfully remediated a Cr(VI)- contaminated alkaline soil.

中文翻译：

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通过将纳米级 FeII-AlIII LDH 悬浮液注入土柱中固定土壤中的 Cr(VI)

摘要 我们合成了纳米级 FeII-AlIII 层状双氢氧化物 (LDH)，并使用分批和柱状实验研究了其在添加 Cr 的碱性壤土中还原固定 Cr(VI) 的效率。批量实验的结果表明，以 Cr(VI) 与 LDH 中结构 FeII 的摩尔比 [FeII(s)] = 0.2，将新鲜的 LDH 悬浮液添加到土壤中，完全固定了 Cr(VI)。柱实验使用相同的 Cr(VI)/FeII(s) 比率，在四种不同的 LDH 悬浮液施用于土壤的模式下进行。由于 LDH 颗粒对土壤的渗透较浅，将 LDH 悬浮液以 2 cm 的压头添加到饱和和非饱和填充土柱中，无法将 Cr(VI) 还原为 Cr(III)。将 LDH 悬浮液注入土柱大大提高了 LDH 颗粒向土壤中的渗透。然而，在饱和土柱中只有 18.8% 的可浸出 Cr(VI) 被固定，而在不饱和柱实验中相同的操作使 Cr(VI) 的固定效率提高到 70.0%，在固定方面有显着的提高。总之，纳米级 FeII-AlIII LDH 被证明是一种快速而强效的还原剂，它成功地修复了受 Cr(VI) 污染的碱性土壤。