Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, Facultad de Ciencias, Campus de Cantoblanco, 28049 Madrid, Spain.
Sci Total Environ. 2012 Mar 1;419:81-9. doi: 10.1016/j.scitotenv.2011.11.054. Epub 2012 Jan 28.
Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions. The separation of mineral materials from a common and abundant natural source, for soil protection purposes, is proposed as an economic and environmentally efficient practice. The liner qualities were compared for their mineralogical, physicochemical and major ions transport and adsorption properties. Although all samples fulfilled hydraulic conductivity requirements, the addition of bentonite to arkose sandstone was determined to be an effective strategy to decrease the permeability of the soil and to improve the pollutants retention. The clay materials from arkose sandstone also contributed to pollutant retention by a significant improvement of the cation exchange capacity of the bulk material. However, the mixtures prepared with clay materials from the arkose, exhibited a slight increase of hydraulic conductivity. This effect has to be further evaluated.
已制备了增强型砂-黏土混合物，并将其评估为考虑用作垃圾填埋衬垫。在受控条件下进行了实验室规模的测试，使用不同的改良天然砂岩使渗滤液通过压实的混合物。压实的样品由硅质砂（从长石砂岩中分离出的石英-长石砂）和黏土（来自长石砂岩的纯化黏土和两种商业膨润土）材料组成，这些材料以不同的比例混合。为了土壤保护目的，从常见且丰富的天然来源中分离矿物质材料被提议为一种经济且环保有效的做法。对其进行了衬垫质量的比较，比较了其矿物学、物理化学和主要离子传输和吸附特性。尽管所有样品都满足水力传导率要求，但向长石砂岩中添加膨润土被确定为降低土壤渗透性和提高污染物保留率的有效策略。长石砂岩的黏土材料也通过显著提高材料的阳离子交换容量来有助于污染物的保留。然而，用长石砂岩的黏土材料制备的混合物的水力传导率略有增加。需要进一步评估此效果。
