Introducing Nanoclay and Silica-based Composites as a New Approach for Improving Chemical and Mechanical Properties of Soil: A Review

Layered silicates (nanoclay) are new types of nanomaterials derived from clay minerals with a wide range of applications in different fields such as catalysts, soil industry, etc. Nanoclays are wide ranges of naturally occurring inorganic minerals with different derivatives. Montmorillonite is a wellknown nanoclay consisting of a 2:1 layered structure with two-silica tetrahedron sandwiching an alumina octahedron. In nature, nanoclays can be found in both crystalline (phyllosilicates) and non-crystalline (imogolite) forms. Nanoclays incorporated into polymer matrices have demonstrated a significant capability to improve the tensile and barrier properties of soil. Nanoclays play a vital role in enhancing soil quality due to their high surface area and porous structure. On the other hand, due to the positive charge of sand grains and the chemical compositions of clay particles, the negatively charged clay particles help create a good condition to improve soil properties. According to the best of our knowledge, there is no review paper to study the role of nanoclays on soil samples. This review paper describes the role of nanoclay compounds in the improved properties of soil samples and introduces different types of modified nanoclay used in soil samples. Reported results showed that nanoclays with complex structures are useful nanomaterials for improving the quality of soil samples.