Department of Environmental Engineering, China Jiliang University, Hangzhou 310018, Zhejiang, China.
School of Environment, Tsinghua University, Beijing, 100084, China.
J Hazard Mater. 2019 Jul 5;373:678-686. doi: 10.1016/j.jhazmat.2019.03.126. Epub 2019 Mar 31.
Disposal of soil washing effluent (SWE) resulting from the surfactant-enhanced remediation of soil containing hydrophobic organic contaminants (HOCs)is complicated because of the presence of high levels of surfactants. The synthesized layered double hydroxides (LDHs), modified with sodium dodecyl sulfonate (SDS) in different loading amounts (organo-LDHs),were evaluated in this study as sorbents for the removal of two typical HOCs, phenanthrene (PHE) and pyrene (PYR),from a simulative SWE. The results showed that the organo-LDHs can effectively sorb PHE and PYR from the SWE within an equilibrium time of 2 h. All isotherms were linear and the sorption capabilities of the organo-LDHs increased almost linearly with the increase in the amount of SDS loaded on the LDHs. Besides, the surface areas of the organo-LDHs decreased sharply with the increase in SDS loading owing to the hindrance of the exposed surface of the LDHs by the incorporated SDS. These findings indicated that partitioning dominated the sorption process rather than adsorption, and the strong affinity of HOCs towards the organic phase in LDHs assisted in the effective removal of polycyclic aromatic hydrocarbons (PAHs) from the SWE. Furthermore, the sorption capabilities of organo-LDHs towards PHE and PYR at the higher loading amounts of SDS were much greater than that of commercial activated carbon at the higher concentration ranges of PAHs.
由于土壤洗涤废水（SWE）中存在大量表面活性剂，因此处理经过表面活性剂增强修复的含有疏水性有机污染物（HOCs）的土壤所产生的 SWE 比较复杂。本研究中评估了用不同负载量的十二烷基磺酸钠（SDS）改性的合成层状双氢氧化物（LDHs）作为吸附剂，用于从模拟 SWE 中去除两种典型的 HOCs，即菲（PHE）和芘（PYR）。结果表明，在 2 h 的平衡时间内，有机 LDHs 可以有效地从 SWE 中吸附 PHE 和 PYR。所有等温线均呈线性，且随着 LDHs 上负载的 SDS 量的增加，有机 LDHs 的吸附能力几乎呈线性增加。此外，由于 SDS 阻碍了 LDHs 的暴露表面，有机 LDHs 的表面积随 SDS 负载量的增加而急剧下降。这些发现表明，分配作用主导了吸附过程，而不是吸附作用，且 HOCs 对 LDHs 中有机相的强烈亲和力有助于有效去除 SWE 中的多环芳烃（PAHs）。此外，在 SDS 较高负载量下，有机 LDHs 对 PHE 和 PYR 的吸附能力远大于在较高 PAHs 浓度范围内的商用活性炭。
