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首页> 外文学位 >Characterization of mineral oil, coal tar and soil properties and investigation of mechanisms that affect coal tar entrapment in and removal from porous media.
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Characterization of mineral oil, coal tar and soil properties and investigation of mechanisms that affect coal tar entrapment in and removal from porous media.

机译：矿物油，煤焦油和土壤特性的表征以及影响煤焦油截留和从多孔介质中去除的机理的研究。

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摘要

Mineral oils and coal tars are complex nonaqueous phase liquids (NAPLs), which can serve as long-term sources of ground water contamination. Very limited data are available on mineral oil and coal tar entrapment in and removal from porous media. Thus, the objectives of this research were to evaluate the behavior of these NAPLs in porous media, and investigate the mechanisms governing NAPL entrapment in and recovery from porous media.; Quantification of properties of three commercial mineral oils and six MGP coal tars reveals that mineral oils are slightly viscous LNAPLs (density: ∼0.88 g/cm3; viscosity: 10--20 cP), whereas coal tars are highly viscous DNAPLs (density: 1.052--1.104 g/cm3; viscosity: 32--425 cP). Measured oil (tar)-water interfacial tensions (IFT) were lower than that of pure NAPLs. Properties of 16 field soil samples (soil particle size distribution, specific surface area, total carbon content, cationic exchange capacity and soil moisture release curves) were characterized. Correlations between residual NAPL saturation and NAPL and soil properties were developed, and show that the entrapment of NAPL dependent upon soil particle size distribution, total carbon content, NAPL viscosity and NAPL-water IFT.; Aqueous pH and ionic strength were found to influence the interfacial properties in tar-water-silica systems. At pHs greater than 7.0, observed reduction in contact angle were attributed to the repulsive electrostatic force between coal tar and solid surface. When pH less than 4, hydration forces played a role on the contact angle decrease. The IFT reduction was resulted from the accumulation of surface-active molecules at the tar-water interface. The effect of ionic strength on interfacial properties was not significant below 0.5 M.; The effects of temperature and surfactant or surfactant/polymer addition on coal tar removal was investigated by conducting coal tar displacement experiments at three different temperatures (22, 35, and 50°C) with sequential flushing of water, surfactant and surfactant/polymer. Coal tar removal from porous media was enhanced by elevating temperature and surfactant flushing due to the viscosity and IFT reduction, respectively. Xanthan gum was used as the polymer to increase the viscosity of the displacing fluid. In summary, these results provide tools for the prediction of NAPL entrapment in porous media, and for the selection of remediation strategies for coal tar contaminated source zone.
机译：矿物油和煤焦油是复杂的非水相液体（NAPL），可以长期作为地下水污染的来源。关于矿物油和煤焦油截留和从多孔介质中清除的数据非常有限。因此，本研究的目的是评估这些NAPL在多孔介质中的行为，并研究控制NAPL截留和从多孔介质中回收的机制。对三种商业矿物油和六个MGP煤焦油的性能进行定量分析表明，矿物油是稍粘的LNAPL（密度：〜0.88 g / cm3；粘度：10--20 cP），而煤焦油是高粘性的DNAPL（密度：1.052） -1.104 g / cm3;粘度：32--425 cP）。测得的油（焦油）-水界面张力（IFT）低于纯净NAPL。表征了16个田间土壤样品的特性（土壤粒径分布，比表面积，总碳含量，阳离子交换容量和土壤水分释放曲线）。发展了残留NAPL饱和度与NAPL与土壤性质之间的相关性，表明NAPL的截留取决于土壤粒径分布，总碳含量，NAPL粘度和NAPL-水IFT。发现水性pH和离子强度影响焦油-水-二氧化硅体系中的界面性质。在pH值大于7.0时，观察到的接触角减小归因于煤焦油和固体表面之间的排斥静电力。当pH小于4时，水合力对接触角的减小起着作用。 IFT的降低是由于焦油-水界面处表面活性分子的积累所致。在0.5 M以下，离子强度对界面性能的影响不明显。通过在三个不同的温度（22、35和50°C）下依次冲洗水，表面活性剂和表面活性剂/聚合物，进行煤焦油置换实验，研究了温度和表面活性剂或表面活性剂/聚合物的添加对煤焦油去除的影响。由于粘度和IFT降低，分别通过提高温度和表面活性剂冲洗，可以提高从多孔介质中去除煤焦油的能力。黄原胶被用作聚合物以增加驱替液的粘度。总而言之，这些结果为预测多孔介质中的NAPL截留量以及为煤焦油污染源区的补救策略选择提供了工具。

著录项

  • 作者

    Kong, Lingjun.;

  • 作者单位

    Georgia Institute of Technology.;

  • 授予单位 Georgia Institute of Technology.;
  • 学科 Engineering Environmental.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 339 p.
  • 总页数 339
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;
  • 关键词

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