The technological use of nanomaterials in soil stabilization, writes AZoNano journal, occurs with reduced environmental impact compared to the impact generated by the use of traditional techniques
by Matteo Cavallito
Nanotechnology and nanomaterials offer important solutions for soil improvement, according to an article published in AZoNano journal. “Nanotechnology has been applied to soil improvement techniques to offer an eco-friendly and cost-effective alternative to traditional techniques,” writes Priyom Bose, a researcher at the University of Madras, India, and an expert in biotechnology.
Nanomaterials, he recalls, possess many biological, mechanical, optical and electrical properties and are defined as such when their structures do not exceed 100 nanometers (one ten-thousandth of a millimeter) in length. “Over the years, nanotechnology applications for soil improvement techniques have improved,” he adds.
Nanomaterials for soil
Soil is composed of soil particles between which water and air are placed. When nanomaterials are added to the soil, their microstructure affects the strength of the soil itself, changing the pore fluid and increasing the binding strength within the particles.
“Owing to their small size, nanoparticles can easily disperse into the pore space between the soil particles, particularly into fine soil particles that are not under high pressure,” the article states.
Traditional techniques used to improve the strength of soil, such as grouting involving the use of cement, sodium silicate or acrylate, can generate high costs by causing high environmental impact. The addition of nanomaterials as soil stabilizers, on the other hand, “ccan significantly reduce environmental disturbance as it does not require high-pressure infusion.” Common nanomaterials, moreover, “are inert and non-toxic, it does not harm the soil and groundwater aquifers.” Finally they can be applied in small quantities.
Examples of new materials, Bose adds, include the use of carbon nanotubes (CNTs) made from graphene. These are “super thin sheet of carbon atoms in a hexagonal arrangement that are rolled into a tube to form CNTs”. In this way they “create a material that is stronger than steel but much lighter in weight.” The resulting product boasts important elastic properties and “it has a high potential to act as a filler within the cement grains to make the composite denser, tougher, and stronger.”
There are other examples. Colloidal silica, the researcher recalls, is an aqueous dispersion of microscopic silica used to improve the resistance to compressive strength of sand.
Nanobentonite, on the other hand, is a processed clay that boasts significant moisture absorption properties and functions as an additive to reduce fluid loss in the rock formation during drilling operations. Laponite, for its part, is composed of synthetic sheets of silicate nanoparticles and is 10 times smaller in size than bentonite. “In an aqueous medium, laponite disperses into a colorless suspension that has good rheological properties” (such as fluidity, resistance to deformation etc., ed.), Bose explains.
The importance of nanosensors
The development of soil nanomaterials represents only one of the possible uses of nanotechnology. This technology, in fact, can be used for additional purposes, including analysis of the fruits of the soil itself. Some specific nanosensors, for example, can be used to detect the presence of pesticides or other harmful substances in food.
Recently, researchers from the Department of Microbiology at Karolinska Institutet in Stockholm demonstrated a new system for making a large number of definitely effective detectors in the laboratory.
The basis of their initiative is the droplet atomization and subsequent combustion of a silver and silicon solution. The operation generates the nanoparticles, which can be deposited directly on a glass substrate, thus creating a new surface nanostructure. Which, the scientists explained. can be used for spectroscopic analysis to detect the chemical composition of a substance-that is, the presence of certain specific molecules. Including those of pesticides.