Yeh Carol Kuei-Jyum, Young Chao-Ching
Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung Shien, Taiwan, ROC.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2003;38(11):2697-709. doi: 10.1081/ese-120024457.
The reduction of contaminants sorbed on the coarse fraction of soils to the level below clean-up requirements is essential for an effective soil washing process. This study investigated the effects of soil texture and surfactant sorption on the reduction of total petroleum hydrocarbons (TPH) in coarse fraction during soil washing. Batch TPH sorption experiments were conducted on soil slurry with various soil fine/coarse ratios and surfactants Octylpheny polyoxyethylene (TX-100) and Dodecylpyridinium chloride (DPC) at the dosage below their saturation levels of sorption. In a sandy loam soil of low silt and clay contents, increasing the fine/coarse ratio from 0.4 to 1.2 without adding surfactants resulted in a reduction of TPH levels in the coarse fraction by 30%. Increasing the fine/coarse ratio along with sorbed surfactant (3000 mg TX-100 or 10,000 mg DPC per kg soil) further reduced TPH concentrations in the coarse fraction. For a silty loam soil already containing a high percentage of fine particles, increasing the fine/coarse ratio from 5.9 to 18.8 without surfactant addition yielded no further TPH reduction in the coarse fraction. On the other hand, surfactant sorption at the fine/coarse ratio of 5.9 improved the washing efficiency of the coarse fraction. These experimental results suggested the importance of high contents of soil fines and surfactant sorption in achieving low contaminant concentrations of coarse fractions during soil washing.
将吸附在土壤粗颗粒部分的污染物减少到清理要求以下的水平，对于有效的土壤清洗过程至关重要。本研究调查了土壤质地和表面活性剂吸附对土壤清洗过程中粗颗粒部分总石油烃（TPH）减少的影响。在不同细/粗比的土壤浆液以及低于其吸附饱和水平剂量的辛基酚聚氧乙烯（TX - 100）和十二烷基吡啶氯化物（DPC）表面活性剂上进行了批量TPH吸附实验。在低粉砂和粘土含量的砂壤土中，在不添加表面活性剂的情况下将细/粗比从0.4增加到1.2，导致粗颗粒部分的TPH水平降低了30%。将细/粗比与吸附的表面活性剂（每千克土壤3000毫克TX - 100或10000毫克DPC）一起增加，进一步降低了粗颗粒部分的TPH浓度。对于已经含有高比例细颗粒的粉质壤土，在不添加表面活性剂的情况下将细/粗比从5.9增加到18.8，粗颗粒部分的TPH没有进一步降低。另一方面，在细/粗比为5.9时的表面活性剂吸附提高了粗颗粒部分的清洗效率。这些实验结果表明，在土壤清洗过程中，高含量的土壤细颗粒和表面活性剂吸附对于实现粗颗粒部分低污染物浓度很重要。
