Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Enqulab Ave., Ghods St., Tehran, Iran.
Environ Monit Assess. 2018 Jun 11;190(7):389. doi: 10.1007/s10661-018-6748-6.
Oily sludge is a stable emulsion of water in oil, containing solid particles, oily hydrocarbons, and metals with different compositions, which is greatly hazardous to the environment; as a consequence, they must be removed or recovered. Recovery methods are usually preferable because of the possibility of valuable oily hydrocarbons recovery as well as environmental protection. Liquid extraction is one of the most effective methods of oily sludge recovery. In this research, hydrocarbon recoveries from oily sludge using liquid extraction with methyl ethyl ketone (MEK) and toluene as polar and non-polar solvents have been studied and compared to each other. Different parameters will affect the quality of extraction process, among which the temperature, time, and solvent to sludge ratio are the most important ones. Response surface methodology was used as a method of experimental design to find the optimum conditions for obtaining maximum recovery. Then, the sludge recovery efficiencies under the optimum conditions for MEK and toluene were determined by gas chromatography and compared to each other. The results showed 30.41 and 37.24% hydrocarbon recovery for MEK and toluene respectively. Since the major composition of the sludge consisted of non-polar components, therefore, non-polar solvent (MEK) shows better efficiency. The optimum conditions of the studies were 20 °C, 19 min, and 6.4/4.2 for MEK and 55 °C, 17 min, and 3.6/3.6 for toluene.
含油污泥是一种油水稳定乳液，其中含有固体颗粒、油性碳氢化合物和不同成分的金属，对环境危害极大；因此，必须将其去除或回收。由于有可能回收有价值的油性碳氢化合物以及保护环境，因此回收方法通常更可取。液-液萃取是回收含油污泥最有效的方法之一。在这项研究中，使用甲基乙基酮 (MEK) 和甲苯作为极性和非极性溶剂从含油污泥中回收碳氢化合物，并对其进行了比较。不同的参数会影响萃取过程的质量，其中温度、时间和溶剂与污泥的比例是最重要的参数。响应面法被用作实验设计的方法，以找到获得最大回收率的最佳条件。然后，通过气相色谱法确定 MEK 和甲苯在最佳条件下的污泥回收率，并对其进行比较。结果表明，MEK 和甲苯的碳氢化合物回收率分别为 30.41%和 37.24%。由于污泥的主要成分是非极性成分，因此非极性溶剂 (MEK) 表现出更好的效率。研究的最佳条件为 MEK 的 20°C、19 分钟和 6.4/4.2，以及甲苯的 55°C、17 分钟和 3.6/3.6。
