Smith James A, Bartelt-Hunt Shannon L, Burns Susan E
Program of Interdisciplinary Research in Contaminant Hydrogeology, Department of Civil Engineering, University of Virginia, P.O. Box 400742, Charlottesville, VA 22904-4742, USA.
J Hazard Mater. 2003 Jan 3;96(1):91-7. doi: 10.1016/s0304-3894(02)00199-1.
We investigate the use of organobentonites as liners for underground gasoline storage tanks to reduce the risk of subsurface contamination. A series of permeability measurements were conducted on two types of organobentonites: benzyltriethylammonium-bentonite (BTEA-bentonite) and hexadecyltrimethylammonium-bentonite (HDTMA-bentonite). Both water and commercial unleaded gasoline were used as the permeant liquids. Results of these measurements indicate that the intrinsic permeability of the organobentonite decreases by one to two orders of magnitude when the permeant liquid is changed from water to gasoline. Results of batch sorption measurements reveal that benzene sorption to both organobentonites from water is greater than benzene sorption to conventional bentonite. The magnitude of benzene sorption is related to the loading of the organic quaternary ammonium cation on the clay. As the HDTMA cation loading increases from 25% of cation exchange capacity (CEC) to 120% of CEC, benzene sorption increases. However, as the BTEA cation loading increases from 40 to 120% of CEC, benzene sorption decreases. Collectively, these results suggest that organobentonites can be used effectively to reduce hydrocarbon migration rates beneath leaking underground gasoline storage tanks, and that the optimal organic cation loading with respect to pollutant sorption may be less than 50% of cation exchange capacity for some organobentonite-solute combinations.
我们研究了使用有机膨润土作为地下汽油储存罐的衬里，以降低地下污染风险。对两种有机膨润土进行了一系列渗透率测量：苄基三乙基铵膨润土（BTEA-膨润土）和十六烷基三甲基铵膨润土（HDTMA-膨润土）。水和商用无铅汽油均用作渗透液。这些测量结果表明，当渗透液从水变为汽油时，有机膨润土的固有渗透率降低了一到两个数量级。批量吸附测量结果表明，水中苯在两种有机膨润土上的吸附量大于在传统膨润土上的吸附量。苯的吸附量与粘土上有机季铵阳离子的负载量有关。随着HDTMA阳离子负载量从阳离子交换容量（CEC）的25%增加到CEC的120%，苯的吸附量增加。然而，随着BTEA阳离子负载量从CEC的40%增加到120%，苯的吸附量减少。总体而言，这些结果表明，有机膨润土可有效用于降低泄漏地下汽油储存罐下方的烃迁移速率，并且对于某些有机膨润土-溶质组合，就污染物吸附而言，最佳有机阳离子负载量可能小于阳离子交换容量的50%。
