Nanotechnology – From the Lab to the Land
Nanotechnology advancements have affected almost every area of modern science, from pharmaceuticals to ceramics. Today, the development of nanotechnology applications in the field of agriculture is revolutionizing the farming industry. With large-scale investments from global food corporations, support from the academic community, and funding from many governments around the world, the opportunities for nanoparticles remain limitless in the agrichemical industry. Nano World News spoke with John Hill, Process and Applications Advisor for NETZSCH Fine Particle Technology in Exton, Pa., about the manufacturing and use of nanoparticles in agriculture.Nano World News: What are the most recent advancements in nanotechnology for agriculture?
John Hill: Techniques at the nano-scale are being applied to enable the targeted delivery of pesticide applications. This includes the insertion of nano-sized active ingredients into pesticides. Commercially, the world’s largest agrichemical company is currently retailing many chemicals that contain nanoemulsions. Nanoemulsions are suspensions of nanoscale particles. Those currently on the market contain uniform suspensions of pesticidal or herbicidal nanoparticles ranging from 200 to 400 nm.
Pesticides and herbicides also use encapsulation and controlled-release methods because formulations that contain nanoparticles within the 100 to 250 nm size range can dissolve in water more effectively. Companies are using nanoparticles in gels, creams, liquids and various other media that play a role in the prevention, treatment and preservation of crops.
NWN: Are nanoparticles only being used in pesticides and herbicides?
Hill: No, nano-sized materials are also being used to create more effective insecticides and fungicides.
NWN: What are the main benefits agriculturalists can expect if they use these new nano-formulations?
Hill: Effectiveness, solubility, stability. The small size of nanoparticles improves the effectiveness of agrichemicals due to more available surface area. Better absorption occurs, and as a result, smaller quantities of the chemicals are needed.
The nanoparticles are more soluble, also due to the high surface area associated with nanoparticle dispersion. Smaller particles dissolve faster and become more readily available for the plant to absorb.
Stability improves because the nanoparticles do not settle in the liquid suspension. The small size also allows for more precise spraying of the suspension by using smaller nozzles and allowing more accurate application. In the soil, nanoparticles migrate quickly and become available for use.
NWN: What are some challenges in manufacturing nanoparticles for this application?
Hill: The R&D process can be long and strenuous. Nanoparticle dispersions require quite a bit of reformulation to produce stable, low-viscosity dispersions. We recommend that our agchem customers start on a small scale with lab-sized machinery that offers accurate scalability to full-size production. Also, some agrichemicals can be quite toxic, so lab machinery allows for smaller capacities, along with proper material handling and safety equipment, before they move onto full-scale production.
NWN: How are companies currently producing agrochemical products?
Hill: Mixers and deaerators produce liquid formulations mostly used in insecticides. Disc mills are used in the liquid suspension products, such as herbicides and fungicides.
Typically, a disk mill will produce a product with an average particle size of 1 to 5 microns in a single pass. This particle size has typically been sufficient for most agrochem applications, and still is.
For dispersible granulates (fungicides), media mills can make the fine particle size dispersion that is then spray-dried to produce the granules.
NWN: What specific technologies does NETZSCH offer for the manufacturing of nanoparticles for agrochem applications?
Hill: For both lab and full-scale production, NETZSCH’s proprietary Zeta™ mill technology produces nanoparticle dispersions. Its high flow recirculation process is the most efficient method to produce the narrow particle size dispersion associated with the nanoparticle dispersions. In addition, the Zeta mill is needed to handle the small media sizes required to produce nanodispersions.
NETZSCH’s most advanced mixer, the PSI-Mix™, effectively makes the premix used in agchem formulations, allowing safe, enclosed powder to feed into the liquid. The PSI-Mix effectively deaerates the dispersion, allowing more efficient size reduction through the milling process. The combination of superior wetting properties, as well as the decrease in foam allows for a higher throughput rate through the media mill.
As a more cost-effective solution, the NMD mixers are well suited for producing the necessary pre-dispersion, but users will sacrifice some of the benefits of the PSI-Mix. For more traditional agchem dispersions, the LME series of mills will produce fine particle dispersions for very large quantities.
NWN: What is the future of nanoparticles in agrichemicals?
Hill: Advancements and new applications are being developed every day, such as new tools for the treatment of plant diseases and disease detection. Sensors and delivery systems are in progress that will help crops combat viruses and pathogens. Nanostructured catalysts will help lower doses of pesticides for even more efficiency. The options are really limitless.