Université de Bourgogne Franche-Comté-Besançon, Institut UTINAM-UMR CNRS 6213, 16, route de Gray, 25030 Besançon, France.
Université de Bourgogne Franche-Comté-Besançon, Institut UTINAM-UMR CNRS 6213, 16, route de Gray, 25030 Besançon, France; Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, UMR-CNRS 7285, F-86073 Poitiers, France.
J Hazard Mater. 2022 Jun 15;432:128703. doi: 10.1016/j.jhazmat.2022.128703. Epub 2022 Mar 15.
The removal of chlorinated organic hydrocarbons (COHs) -DNAPLs was studied in permeability-contrasted sandboxes with an egg-box shaped substratum. Aqueous solutions were compared to viscous shear-thinning fluids (xanthan solution and foam). Interfacial and viscous effects were compared by increasing the capillary number of injected fluids. Non-spatially targeted DNAPL recovery (NSTR) where the driving force was the injection pressure, was compared to spatially targeted DNAPL recovery (STR) where a pumping system allowed the controlled flow. A historical contamination made of a complex mixture of COHs and hexachlorobutadiene (HCBD) as a model were used. NSTR results showed that DNAPL recovery with non-viscous liquids did not exceed 40%. The best results were obtained for xanthan solutions with surfactant ~ 1.3 ×CMC for which pure phase recovery amounted to 88% and 93% for HCBD and for the historical DNAPL, respectively. The STR strategy showed similar recovery yields, whereas xanthan concentrations were 10-times lower. Mass balances on DNAPL showed that at most, 0.15% of COHs was dissolved in the aqueous effluents. NZVI (1 g.l) were delivered in xanthan in view of the chemical degradation of residual COHs and showed a 65% transmission through the low permeability soil.
采用具有蛋盒形状基底的渗透性对比砂箱研究了去除含氯有机碳氢化合物 (COHs) -DNAPL。比较了水相溶液和粘性剪切稀化流体（黄原胶溶液和泡沫）。通过增加注入流体的毛细数来比较界面和粘性效应。非空间靶向 DNAPL 回收（NSTR）的驱动力是注入压力，与空间靶向 DNAPL 回收（STR）相比，后者的泵送系统允许控制流量。使用了由 COHs 和六氯丁二烯（HCBD）的复杂混合物作为模型的历史污染。NSTR 结果表明，非粘性液体的 DNAPL 回收率不超过 40%。对于表面活性剂约为 1.3×CMC 的黄原胶溶液，获得了最佳结果，HCBD 和历史 DNAPL 的纯相回收率分别达到 88%和 93%。STR 策略显示出相似的回收产率，而黄原胶浓度低 10 倍。DNAPL 的质量平衡表明，在水相流出物中最多只有 0.15%的 COHs 溶解。考虑到残余 COHs 的化学降解，在黄原胶中输送了 1g.l 的 NZVI，并通过低渗透率土壤传输了 65%。
