About the sector - EUON
Environment - Overview - About the Sector - Text
Nanotechnology1 is applied in a range of different environmental applications relevant to, for instance, water treatment, remediation and environmental sensing. Within water and wastewater technology, three different major categories exist: nanoadsorbents, nanocatalysts and nanomembranes.
Nanomaterial applications for wastewater treatment is a widely researched topic with over 6,000 scientific publications available since 1995. At the earlier stages of research of nanotechnology application in wastewater treatment, titanium dioxide and nanocomposites were mostly discussed. In the newest research, scientists highlight the potential of carbon nanotubes, titanium dioxide nanotubes, silver nanoparticles, graphene oxide, graphene and magnetic nanoparticles.2
Due to their small size, large surface areas and a large number of active adsorption sites, nanoadsorbents offer an improved possibility of absorbing pollutants on a solid surface compared to the conventional adsorbents. This again facilitates the removal of organic or inorganic pollutants in water and wastewater treatments. Nanoadsorbents can be based on, for instance, carbon and metal oxide. In order for the use of nanoadsorbents to be useful, they must be nontoxic recyclable and pollutants should be easily removed from their surface. Compared to their bulk counterparts, nanocatalysts have a significantly enhanced catalytic activity that is widely used for water treatment and degradation of organic contaminants. Examples of nanocatalysts used for wastewater treatment include Fe2O3 and nano-nickel zinc ferrite and platinum nickel nanoalloys to degrade methylene blue dyes and 4-chlorophenol. TiO2 and ZnO nanoparticles have also been used for degradation of organic contaminants in water and air. Nanomembranes are also widely used in water and wastewater treatment due to their lower operational costs and reduced energy consumption compared to reverse osmosis. Examples of nanomaterials used in such membranes include zeolites, Ag, TiO2, and carbon nanotubes (CNTs).
Nanotechnology has also been used in the remediation of pollutants or contaminants from groundwater, surface water, soil and sediment. For instance, nZVI nanoparticles have been used for in situ remediation treatment of groundwater and wastewater contaminated with various organic and inorganic pollutants for more than two decades. Other materials that have been used include CNTs, nanoscale zeolites, nanofibers, and metal oxides. Some nanomaterials, such as nZVI agglomerate in the aqueous environment, can cause a decrease in their dispersibility and mobility, thereby reducing their overall usefulness. In order to prevent agglomeration, nZVI is often combined with metals such as Pd, Pt, Ag, Cu, and Ni. Similarly, starch and carboxymethyl cellulose have been used in order to prevent agglomeration of magnate nanoparticles when it comes to soil remediation.
Environmental monitoring and sensing are other fields in which nanotechnology is used. Sensors based on nanotechnology can detect pollutants such as heavy metals and organic pollutants at very low concentrations, which is useful when it comes to monitoring air and water quality. For instance, the detection of harmful gases such as hydrogen sulfide, sulphur dioxide and nitrogen dioxide has been enabled by the use of nanomaterials in sensors. Examples of nanomaterials used include nanogold, quantum dots, carbon dots and nanometal organic frameworks.3,4
1 This section comprises the text which is already available on the website of the EUON NanoData with updates where relevant
2 Manžuch, Z., Akelytė, R., Camboni, M., Carlander, D., García, R. P., & Kriščiūnaitė, G. (2021). Study on the product lifecycles, waste recycling and the circular economy for nanomaterials. Commissioned by ECHA, European Observatory of Nanomaterials. Available at: https://euon.echa.europa.eu/documents/2435000/3268576/nano_lifecycles_euon_en.pdf/107f2bd6-8967-5466-8f48-5610d9120bbe?t=1636969415023
3 Saleem, H., Zaidi, S. J., Ismail, A. F., & Goh, P. S. (2022). Advances of nanomaterials for air pollution remediation and their impacts on the environment. Chemosphere, 287(9), 132083.
4 Ibrahim, R. K., Hayyan, M., AlSaadi, M. A., Hayyan, A., & Ibrahim, S. (2016). Environmental application of nanotechnology: Air, soil, and water. Environmental Science and Pollution Research, 23(14), 13754–13788.