The Future of Soil: Nanotechnology's Impact on Agriculture

Fremont, CA: Traditional soil development techniques are threatened by the growing urbanization and industrialization of the world. Traditionally, cement and chemical grouts (such as sodium silicate, acrylate, and epoxy) are utilized to increase soil strength. However, these methods can cause severe disturbances, pollute the environment, and are difficult to apply broadly.

Nanomaterials for Soil Improvement

Materials that are smaller than 100 nm and have a wide range of mechanical, optical, electrical, and biological capabilities are referred to as nanomaterials. Laponite, bentonite, colloidal silica, and carbon nanotubes (CNTs) are the four major nanomaterials to improve soil. Additional nanomaterials used to enhance soil characteristics include fullerenes, titanium dioxide (TiO2), zinc oxide (ZnO), bimetallic nanoparticles, nanoscale zerovalent iron (nZVI), and multiwalled carbon nanotubes (MWCNTs). 

The Fundamental Process of Nanomaterials for Increasing Soil Density

The soil is a three-phase media comprising soil particles, water, and air. The pore water pressure significantly influences the amount of soil strength. Nanomaterials strengthen soil by altering the pore fluid and enhancing the connection between the particles. Due to their small size, nanoparticles are generally well-suited to disperse into finer soil particles not subjected to strong pressure in the pore spaces between them.

The microstructure of nanoparticles affects the strength of the soil when they are applied. Compared to three-dimensional nanoparticles (like colloidal silica), the two-dimensional structure of nanoparticles (like CNT) has a different effect on the soil. Because certain soil nanoparticles interact in a nanoparticle-water suspension, their capacity to strengthen soil is influenced by the rheological features of the suspension.

The specific surface area of the nanoparticle increases as the particle size decreases. This suggests a higher atomic surface area, which results in a greater capacity for ion exchange and a higher level of particle contact. The presence of nanoparticles enhances the buildup of pore water. Thus, the plastic and liquid limits are larger in soil that contains nanoparticles. This demonstrates that quantum mechanical theories are more applicable than classical mechanics, explaining particles' motion state and energy at the nanoscale level.

Benefits of Using Nanomaterials for Soil Improvement Techniques Instead of Conventional Materials

As was already established, adding nanomaterials like colloidal silica and carbon nanotubes (CNTs) greatly increases the strength of the soil, especially its compressive strength and resistance to liquefaction. Utilizing nanoparticles is more economical and environmentally favorable than conventional grout materials.

Conventional methods of improving soil, including mechanical reinforcements, come with a hefty price tag and negative environmental effects. Another popular method for enhancing soil strength is chemical grouting, which entails putting designed slurries in the desired location. A pressure transmission mechanism then compresses it to reinforce the flimsy base. Cement and solutions, like epoxy, sodium silicate, and acrylate, are frequently used as grouting materials.

Since high-pressure infusion is unnecessary when adding nanomaterials as stabilizers, environmental disturbance can be greatly reduced. This method works in both developed areas with buildings and barren terrain. The soil and groundwater aquifers are not harmed by the nanomaterials used to improve soil since they are non-toxic and inert. Furthermore, this method is economical because relatively few nanomaterials are needed for efficient soil fortification.