Arsenic (As)-contaminated soils occur widely worldwide. In the present study, three low-cost Fe/Al-based materials, including red soil (RS), sponge iron filter (SIF) and Al-based water treatment sludge (WTS), were applied as amendments to remediate As-contaminated soils under anoxic conditions. After 180 d of incubation, the proportion of the sum of nonspecifically absorbed As (F1) and specifically absorbed As (F2) to the total As was reduced by 6%, 52% and 13% with 5% of RS, SIF and WTS addition, respectively, compared to the control soil (31%). The results showed that among the three amendments, SIF was the most effective at decreasing As bioaccessibility in soils. Compared with RS and WTS, SIF intensified the decrease of labile fractions and the increase of unlabile fractions, and the redistribution of the amorphous oxide-bound fraction (F3) and crystalline hydrous oxide-bound fraction (F4) occurred in the SIF-amended soil. Moreover, the As stabilization processes were divided into two stages in the control and RS-amended soil, while the processes were divided into three stages in both SIF- and WTS-treated soil. The As stabilization processes in all treated soils were characterized by the transformation of labile fractions into more immobilizable fractions, except for F4 transforming into F3 in the first stage in SIF-amended soil. Correspondingly, inner-surface complexation and occlusion within Fe/Al hydroxides were the common driving mechanisms for the transformation of As fractions. Therefore, taking into consideration the results of this study, SIF could be a more promising alternative than the other two materials to passivate As in anoxic soils.

中文翻译：

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使用低成本的铁/铝基材料在缺氧土壤中砷的生物可及性和分馏与稳定的关系：一项长期实验。

受砷污染的土壤在世界范围内广泛存在。在本研究中，三种低成本的铁/铝基材料，包括红壤（RS），海绵铁滤池（SIF）和铝基水处理污泥（WTS）被用作修正剂，以修复被As污染的土壤在缺氧条件下。孵育180天后，添加5％的RS，SIF和WTS后，非特异性吸收的As（F1）和特异性吸收的As（F2）之和与总As的比例分别降低了6％，52％和13％。与对照土壤（31％）相比。结果表明，在这三个修正案中，SIF在降低土壤中As生物可及性方面最有效。与RS和WTS相比，SIF增强了不稳定部分的减少和不稳定部分的增加，SIF改良土壤中发生了无定形氧化物结合部分（F3）和结晶性含水氧化物结合部分（F4）的重新分布。此外，在对照土壤和经RS改良的土壤中，砷稳定过程分为两个阶段，而在经过SIF和WTS处理的土壤中，As稳定过程分为三个阶段。在所有处理过的土壤中，砷的稳定过程的特征是不稳定组分转化为固定性更高的组分，除了在第一阶段经过SIF改良的土壤中F4转化为F3以外。相应地，内表面络合和Fe / Al氢氧化物内的吸留是As组分转化的常见驱动机制。因此，考虑到这项研究的结果，