Table of Contents
Nanocatalysts
A lot of interest has been generated by nano-catalyst surface modification due to its remarkable photocatalytic activity with minimal secondary pollution. Photocatalytic oxidation (PCO) is a promising method for the elimination of volatile organic compounds (VOCs) due to its increased activity and lower secondary contamination.
Low catalytic efficiency and catalyst stability are two of the drawbacks. Therefore, new approaches to catalyst preparation and enhancing the effectiveness of catalysts should be monitored and given more consideration in future research.
Nanocatalysts large volume-to-surface ratio and high area of surface give them some special physicochemical properties. They are widely used to transform exhaust gases into products that are either safer or more beneficial. Here, more recent methods that are effective at lowering exhaust emissions and enhancing engine performance—such as the three-way catalytic converters (TWC), selective catalytic (SCR), etc are covered (Ningthoujam et al., 2022).
Nanotechnology
“The area of technology that works with tolerances and dimensions smaller than 100 manometers, particularly when manipulating single atoms and molecules is called nanotechnology.”
Applications of Nanotechnology to Environmental Issues
- Reducing the amount of pollution produced while making materials.
- Generating electricity with solar cells at a competitive price.
- Boosting the amount of electricity produced by wind turbines.
- Clearing out organic chemicals that are contaminating groundwater.
- Removing spilled oil.
- Agrochemical nanoformulations for the application of fertilizers and pesticides to enhance crop yields.
- Crop protection employs nanosensors to detect crop diseases and agrochemical residues.
Nanocatalysts for Reducing Smog in Urban Areas
Air pollution that obstructs vision is called smog. The combination of smoke and fog was originally referred to as “smog” in the early 1900s (Polivka, 2018). Burning coal was usually the source of the smoke. Health issues brought on by smog include respiratory distress, asthma, lowered immunity to lung illnesses, colds, and irritated eyes. Smog’s ozone can harm trees and plants, and the haze obscures vision. This is especially apparent when looking at mountains and other breathtaking views, like those found in national parks.
Simple catalyst separation and quick chemical conversion with increased yield are made possible by nanocatalysts (Liu et al., 2016). The nanosized catalysts in a uniform nanocatalysis reaction maintain maximum contact with the reactants; in a heterogeneous nanocatalyst reaction, on the other hand, the reactive solvents become insoluble.
Smog Reduction
The majority of nanocatalysts are composed of nanoparticles of metal and semiconducting substances, and they have a great deal of potential for use against radioactive materials, bacteria, viruses, and extremely concentrated organic contaminants. It falls under the category of advanced development and uses a different approach to help address the global issue of water pollution (Mohamed et al., 2012). The majority of them are anti-microbial, Fenton-based, and photocatalysts. Fenton, which includes Fe2O3 nanoparticles (NPs), can interact with other compounds to form novel nanocomposites that are useful and accelerate the rate of degradability.
By developing intelligent systems like screening nanosensors, nanocatalysts that absorb and expel polluting gases, and fuel additives that incorporate nanomaterials, nanotechnology can significantly contribute to the regulation and reduction of air pollution from automobiles.
Nano-adsorbent and their classifications
The various forms of pollution that humans cause are gradually contaminating water sources, which has a reversible effect on human health. Therefore, the time has come to implement some clever, time-saving, low-cost technology to filter and remove impurities from wastewater. Numerous traditional technologies have been employed to remove pollutants from water sources. The use of nano-adsorbent technology in the treatment of wastewater has become increasingly important among these. The nanomaterial has a higher capacity for adsorbing contaminants from wastewater, both organic and inorganic. Because of their distinct physical and chemical characteristics, nano adsorbents are superior to standard adsorbents in a number of applications (Raza et al., 2021).
Nature of Adsorption of Nanocatalysts
Based on how the particle sticks to the surface, adsorption can be classified as physical, chemical, or ion exchange adsorption.
(a) Physical adsorption:
This kind of adsorption is not related to the sharing and pairing of electrons; instead, non-covalent bonds facilitate the Vander Waals interaction, resulting in the source of this adsorption type. It is a reversible procedure.
(b) Chemical adsorption:
This occurs when an adsorbent and an adsorbate form a chemical bond; the material has chemisorbed on a solid shallow is difficult to remove. That makes the process irreversible. This chemisorption is limited to monolayer processes.
(c) Ion exchange adsorption:
This occurs when oppositely charged ions are exchanged between adsorbate and the adsorbent.
Nanocatalysts Reducing Particulate Matter in Urban Areas
What is Particulate Matter?
Particles (tiny pieces) of liquids or solids in the air are what cause particle pollution, also known as particulate matter (PM). These particles could consist of: Dust, Soot, Smoke, Dust,Droplets of fluid.
Certain particles are large enough (or show up dark enough) to be seen; smoke, for instance, is frequently visible in the atmosphere. Some are so tiny that they are invisible from above. Primary and secondary sources are the two categories of sources that can produce particle pollution. Particulate pollution is the direct result of primary sources. Primary sources include things like forest fires and wood stoves.
Particulate matter can form from gases released by secondary sources. Coal fires and power plants are two instances of secondary sources (Alex et al., 2022). Other frequent sources of particulate matter include factories, automobiles and vehicles, and construction sites. These sources can be classified as primary or secondary. PM 2.5 is found in smoke from fires as well as emissions (releases) from factories, power plants, and automobiles and trucks.
How PM is Reduced?
Because nanotechnology reduces particulate matter, it can also be used to stop pollution from starting. Its uses include the production of environmentally friendly materials, coatings, and biocides that stop dangerous substances from being released into the environment. Catalyst separation and quick chemical conversion with increased yield are made possible by the use of nanocatalysts.
The nanosized catalysts in a uniform nanocatalysis reaction maintain maximum contact with the reactants; in a heterogeneous nanocatalyst reaction, on the other hand, the reactive solvents become insoluble. The effect of the quantum size, which expands the energy differences and contracts particle size, is the primary benefit of the nanoscale. Numerous benefits of the photodegradation process include its low cost, reusability, and generally full decomposition.
Conclusion
Different forms of nanomaterials—inorganic, carbonaceous, and polymeric—are successfully used for a variety of environmental remediation applications. An extensive assessment of the types of contaminants to be removed, the ease of getting to the polluted spot, the quantity and number of materials required for successful remediation, and the recovery of the nanomaterials and nanocatalyst used are all necessary when using nanoparticles to remove environmental pollution.
The use of nanocatalysts in environmental restoration has only been covered in general terms because each material has advantages and disadvantages based on how effectively it functions. It is also found that even with a large body of study on nanocatalysis, many issues remain regarding the specific applications of nanotechnology.
Future development will face significant challenges in creating novel ideas like highly effective, eco-friendly nano-based components and nanoparticles with high quality that are sustainable for cleanup at a predictable cost. Furthermore, the task of developing self-cleaning materials is competitive. Evaluating the risk and possible impacts of nanomaterials on the environment and human health is equally essential.
References
Alex, K. V., Kamakshi, K., Silva, J. P. B., Sathish, S., & Sekhar, K. (2022). Automobile exhaust nanocatalysts. In Nanotechnology in the Automotive Industry (pp. 529-560). Elsevier.
Liu, H., Guan, J., Mu, X., Xu, G., Wang, X., & Chen, X. (2016). Nanocatalysis. Encyclopedia of Physical Organic Chemistry, 1-75.
Mohamed, R., McKinney, D., & Sigmund, W. (2012). Enhanced nanocatalysts. Materials Science and Engineering: R: Reports, 73(1), 1-13.
Ningthoujam, R., Singh, Y. D., Babu, P. J., Tirkey, A., Pradhan, S., & Sarma, M. (2022). Nanocatalyst in remediating environmental pollutants. Chemical Physics Impact, 4, 100064.
Polivka, B. J. (2018). The great London smog of 1952. AJN The American Journal of Nursing, 118(4), 57-61.
Raza, W., Saeed, S., Saulat, H., Gul, H., Sarfraz, M., Sonne, C., Sohn, Z.-H., Brown, R. J., & Kim, K.-H. (2021). A review on the deteriorating situation of smog and its preventive measures in Pakistan. Journal of Cleaner Production, 279, 123676.
Author detail:
Razia Yaseen, Aisha Ghaffar
Department of Chemistry, University Of Agriculture Faisalabad, Sub-Campus Toba Tek Singh
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