Recent experimental studies have shown that it is possible to improve the hydraulic and reactive behaviour of permeable reactive barriers (PRBs) composed of zero-valent iron (ZVI) by admixing this reactive medium with volcanic materials such as lapillus or pumice. In this study, the adsorption behaviour of lapillus and pumice was evaluated through batch tests carried out using nickel- and zinc-contaminated solutions at three different initial concentrations (5, 10 and 50 mg/l). It was observed that the lapillus sorption capacity is four and eight times higher than that of pumice for nickel and zinc, respectively. The comparison of column tests results, carried out using mixtures of ZVI/pumice and ZVI/lapillus with two different contaminated solutions (nickel and zinc at initial concentration of 50 mg/l), has shown that the best performance is by the ZVI/lapillus mixtures. In fact, thanks to the contribution of lapillus to contaminant removal, the use of ZVI/lapillus mixtures would allow reducing PRB thickness compared to the use of ZVI/pumice mixtures when the same mass of ZVI is considered. A column test carried out with lapillus only has also shown that it is possible to use the latter as a reactive medium in PRBs in the presence of low concentrations of contaminants.

中文翻译：

---

渗透性反应性屏障中Fe0 /浮石和Fe0 / lapillus混合物的比较

最近的实验研究表明，可以通过将这种反应性介质与火山物质（如天青石或浮石）混合来改善由零价铁（ZVI）组成的可渗透反应性屏障（PRB）的水力和反应行为。在这项研究中，通过使用镍和锌污染的溶液在三种不同的初始浓度（5、10和50 mg / l）下进行的分批测试，评估了紫菜和浮石的吸附行为。观察到，天花对镍和锌的吸附能力分别比浮石高四倍和八倍。使用ZVI /浮石和ZVI / lapillus与两种不同污染溶液（初始浓度为50 mg / l的镍和锌）的混合物进行柱测试结果的比较，已经表明，最好的性能是ZVI / lapillus混合物。实际上，由于考虑到天青石对污染物去除的贡献，与ZVI /浮石混合物的使用相比，当考虑相同质量的ZVI时，使用ZVI /天青石的混合物可以减少PRB的厚度。仅用lapillus进行的柱试验还表明，在低浓度污染物存在下，可以将其用作PRB中的反应介质。