Different physicochemical and biological treatments have been used to treat oil sludges, and oil recovery techniques are preferred such as oil sludge washing (OSW) with surfactants and co-solvents. Toluene is commonly used as co-solvent, but it is non-benign to the environment. This study tested alternative co-solvents (n-pentane, n-hexane, cyclohexane, and isooctane) at 1:1 and 2:1 C/OS (co-solvent to oil sludge ratio). Also, this study evaluated the effect on the oil recovery rate (ORR) of three main parameters in the washing: type, concentration, and application ratio (S/OS) of surfactants to oil sludges. To date, no study has assessed these parameters in the washing of oil sludges from different sources. Four types of oil sludges and five surfactants (Triton X-100 and X-114, Tween 80, sodium dodecyl sulphate (SDS), and rhamnolipid) were used. The results showed that cyclohexane had high ORR and could be used instead of toluene because it is more benign to the environment. The S/OS ratio had a high effect on the ORR and depended on the type of oil sludge. Rhamnolipid, Triton X-100, and Triton X-114 had the highest oil recovery rates (40 - 70%). In addition, it was found that the surfactant concentration had no effect on the ORR. Consequently, the addition of surfactant was not significantly different compared to the washing with no surfactants, except for one sludge. The use of the surfactant in the washing solution can help in the selective extraction of specific oil hydrocarbon fractions in the recovered oil to assess its potential reuse as fuel. Further recommendations were given to improve the OSW process.

中文翻译：

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用表面活性剂和助溶剂洗涤油泥：从不同类型的油泥中回收油。

已经使用不同的物理化学和生物处理来处理油泥，并且优选采油技术，例如使用表面活性剂和助溶剂的油泥洗涤（OSW）。甲苯通常用作助溶剂，但它对环境无害。本研究测试了 1:1 和 2:1 C/OS（共溶剂与油泥的比率）的替代助溶剂（正戊烷、正己烷、环己烷和异辛烷）。此外，本研究还评估了洗涤中三个主要参数对采油率 (ORR) 的影响：表面活性剂与油泥的类型、浓度和施用比率 (S/OS)。迄今为止，还没有研究评估洗涤不同来源的油泥时的这些参数。使用了四种类型的油泥和五种表面活性剂（Triton X-100 和 X-114、吐温 80、十二烷基硫酸钠 (SDS) 和鼠李糖脂）。结果表明，环己烷具有较高的ORR，可以代替甲苯使用，因为它对环境更友好。S/OS 比对 ORR 有很大影响，并且取决于油泥的类型。鼠李糖脂、Triton X-100 和 Triton X-114 的采油率最高 (40 - 70%)。此外，发现表面活性剂浓度对 ORR 没有影响。因此，与没有表面活性剂的洗涤相比，表面活性剂的添加没有显着差异，除了一种污泥。在洗涤溶液中使用表面活性剂有助于选择性提取回收油中的特定油烃馏分，以评估其作为燃料的再利用潜力。还提出了改进 OSW 流程的进一步建议。