Jerez Jorge, Flury Markus, Shang Jianying, Deng Youjun
Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164, USA.
J Colloid Interface Sci. 2006 Feb 1;294(1):155-64. doi: 10.1016/j.jcis.2005.07.017. Epub 2005 Aug 8.
The objective of this work was to coat aluminosilicate clays on an inert silica support, and to characterize the properties and stability of the clay-silica coating. Two polymers, polyacrylamide (PAM) and polyvinyl alcohol (PVA), were used to bind kaolinite, illite, and smectite onto silica grains. The clay-polymer composites were studied by X-ray diffraction, FTIR, and electrophoretic mobility. Clay coatings on silica grains were characterized by mass coverage, scanning electron microscopy, specific surface area, and pH stability. Silica sand was successfully coated with clays by using the two polymers, but with PVA, the clay coating had a greater mass coverage and was more stable against pH variations. Less polymer was needed for the clay coating using PVA as compared to using PAM. Clay-polymer complexes and pure clay minerals had similar cation exchange capacities and electrophoretic mobilities, indicating that overall surface charge of the clays was little affected by the polymers. Some decrease in hydrophilicity was observed for illite and smectite when clays where coated with the polymers. The methodology reported here allows the generation of a clay-based porous matrix, with hydraulic properties that can be varied by adjusting the grain size of the inert silica support.
这项工作的目的是将铝硅酸盐粘土涂覆在惰性二氧化硅载体上，并表征粘土-二氧化硅涂层的性质和稳定性。使用两种聚合物，即聚丙烯酰胺（PAM）和聚乙烯醇（PVA），将高岭土、伊利石和蒙脱石粘结到二氧化硅颗粒上。通过X射线衍射、傅里叶变换红外光谱（FTIR）和电泳迁移率对粘土-聚合物复合材料进行了研究。通过质量覆盖率、扫描电子显微镜、比表面积和pH稳定性对二氧化硅颗粒上的粘土涂层进行了表征。使用这两种聚合物成功地在硅砂上涂覆了粘土，但使用PVA时，粘土涂层具有更大的质量覆盖率，并且对pH变化更稳定。与使用PAM相比，使用PVA进行粘土涂层所需的聚合物更少。粘土-聚合物复合物和纯粘土矿物具有相似的阳离子交换容量和电泳迁移率，这表明聚合物对粘土的总表面电荷影响很小。当用聚合物涂覆粘土时，观察到伊利石和蒙脱石的亲水性有所降低。本文报道的方法可以生成一种基于粘土的多孔基质，其水力性质可以通过调整惰性二氧化硅载体的粒度来改变。
