地学前缘 ›› 2016, Vol. 23 ›› Issue (5): 301-309.DOI: 10.13745/j.esf.2016.05.029

• 非主题来稿选登 • 上一篇    

重非水相液体与水相界面面积的二维实验研究

 李木子, 万力   

  1. 1. 中国地质大学(北京) 水资源与环境学院, 北京 100083
    2. Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ 85721, USA
    3. 北京师范大学 水科学研究院, 北京 100875
  • 收稿日期:2016-03-09 修回日期:2016-06-03 出版日期:2016-09-15 发布日期:2016-09-15
  • 通讯作者: 万力(1962—)，男，教授，主要从事地下水环境及数值模拟研究。E-mail:wanli@cugb.edu.cn
  • 作者简介:李木子(1987—)，男，博士研究生，地下水科学与工程专业。

Experimental analysis of DNAPLwater interfacial areas in a twodimensional flow cell.

 LI  Mu-Zi, MO  Li   

  1. 1. School of Water Resources and Environment, China University of Geosciences(Beijing), Beijing 100083, China
    2. Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ 85721, USA
    3. College of Water Sciences, Beijing Normal University, Beijing 100875, China
  • Received:2016-03-09 Revised:2016-06-03 Online:2016-09-15 Published:2016-09-15
  • Supported by:

    国家自然科学基金项目(41302179，41372233)

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摘要：

多孔介质中重非水相液体(Dense NonAqueous Phase Liquid，DNAPL)与水相的界面面积是影响DNAPL在地下水中溶解速率的关键参数。本文通过二维均质砂箱实验，运用界面分配示踪法和体积分配示踪法分别测定DNAPL与水相的界面面积(单位介质体积内的面积，Anw)和DNAPL饱和度(Sn)，并研究两者之间的相关关系。使用C18H29NaO3S(SDBS)作为界面分配示踪剂，Alcohol(2,4Dimethyl3Pentanol)作为体积分配示踪剂，CaBr2作为保守示踪剂。利用Fe2+催化的Na2S2O8对DNAPL进行原位氧化修复，改变Anw和Sn。结果表明，通过定量(用孔隙体积数PV值衡量)加入Na2S2O8，Anw由206 cm2逐渐降为37 cm2，下降速率约为14 cm2/PV；Sn由1.34%逐渐降为0.33%，下降速率约为0.1%/PV；Anw和Sn之间具有良好的线性关系(Anw=146×Sn,R2=0.987)。此关系可用于估算多孔介质中DNAPL与水相之间的界面面积。对实验影响因素的分析表明，孔隙度的增大(变化率为20.7%)使示踪剂穿透曲线出现肩现象和拖尾现象，导致保守示踪剂的保留时间增加5.6%，界面面积减小6.8%。

关键词: 砂箱, DNAPL, 界面分配, 体积分配, 过硫酸盐

Abstract:

The interfacial area between dense NonAqueous Phase Liquid (DNAPL) and water in porous media is a key parameter determining the dissolution rate of DNAPL in groundwater. In the present study, the specific DNAPLwater interfacial area (Anw) and DNAPL saturation (Sn) were respectively measured by using interfacial partitioning and bulk partitioning tracer tests in a homogeneous twodimensional flow cell. The relationship between Anw and Sn was also analyzed. C18H29NaO3S (SDBS), Alcohol (2,4Dimethyl3Pentanol), and CaBr2 were used as the interfacial partitioning tracer, bulk partitioning tracer, and nonreactive tracer, respectively. Fe2+activated persulfate was used for insitu chemical oxidation (ISCO) remediation, to change Anw and Sn with increased pore volumes (PV) of persulfate. The results showed that, Anw decreased from 206 cm2 to 37 cm2 by the rate of 14 cm2/PV and Sn decreased from 1.34% to 0.33% by the rate of 0.1%/PV. The observed interfacial area decreased linearly with the decreasing of the NAPL saturation (Anw=146×Sn, R2=0.987), which can be used as a simple method to estimate the interfacial area between NAPL and water in porous media. The analysis of impacts showed that, the breakthrough curves of tracers exhibited shoulder and tailing because of the increase of porosity with the variation rate 20.7%. As a result, the retention time of nonreactive tracers increased 5.6%, while the interfacial area decreased 6.8%.

Key words: flow cell, DNAPL, interfacial partitioning, bulk partitioning, persulfate

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