Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Apdo. 1052, 41080 Sevilla, Spain.
Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain.
Sci Total Environ. 2019 Feb 25;653:384-392. doi: 10.1016/j.scitotenv.2018.10.316. Epub 2018 Oct 29.
This study evaluated the effect of several cyclodextrins (CDs) and a rhamnolipid (RL) on the removal of polycyclic aromatic hydrocarbons (PAHs) from a co-contaminated soil which had received historically creosote and inorganic wood preservatives for almost 100 years, and the effect of such extractions on the potentially toxic elements (PTEs). The influence on such processes of an electrolyte (0.01 M Ca(NO)) was also studied. Up to 15.4% of the ∑16 PAHs were extracted using RL in the absence of the electrolyte as washing solution, but decreases until reaching 0.60% in the presence of Ca due to RL precipitation and partial inactivation. Only up to 2% of the ∑16 PAHs was extracted with CDs (4-ring PAHs in higher concentrations), but the electrolyte had no effect on extraction. In relation to PTEs, CDs proved to be inefficient for their extraction, and even RL in the presence of the background electrolyte. But in the absence of electrolyte PTEs extraction by RL increased. Apart from that, the availability of Ni, Cr, and As, those more associated to Fe and Al soil surfaces, increased after extraction with RLs in the presence of Ca (about 100% for Cr and Ni and 200% for As). Under these conditions Fe and Al availability increased two- and ten-fold, respectively, indicating that Fe-Al soil surfaces were altered. Therefore, the ionic strength and the cations present in the soil solution of soils have to be considered when RLs are used as extractants for remediation purposes.
本研究评估了几种环糊精（CDs）和鼠李糖脂（RL）对受历史悠久的杂酚油和无机木材防腐剂污染近 100 年的共污染土壤中多环芳烃（PAHs）去除的影响，以及这些提取对潜在有毒元素（PTEs）的影响。还研究了电解质（0.01 M Ca(NO)) 对这些过程的影响。在没有电解质作为洗涤溶液的情况下，RL 可提取高达 15.4%的∑16 PAHs，但由于 RL 沉淀和部分失活，在存在 Ca 的情况下，提取量降至 0.60%。仅用 CDs（四环 PAHs 浓度较高）提取了高达 2%的∑16 PAHs，但电解质对提取没有影响。就 PTEs 而言，CDs 对其提取效率不高，即使在存在背景电解质的情况下 RL 也是如此。但在没有电解质的情况下，RL 对 PTEs 的提取增加。除此之外，在存在 Ca 的情况下，RL 提取后 Ni、Cr 和 As 的可用性增加，这些元素与 Fe 和 Al 土壤表面的结合更为紧密（Cr 和 Ni 增加约 100%，As 增加 200%）。在这些条件下，Fe 和 Al 的可用性分别增加了两倍和十倍，表明 Fe-Al 土壤表面发生了变化。因此，在将 RL 用作修复目的的提取剂时，必须考虑土壤溶液中离子强度和存在的阳离子。
