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Environmental protection is one of the critical challenges faced by the human race. Over the years, we have unintentionally devastated our surroundings by creating and discarding plastics, contributed to climate change by mining and burning fossil fuels, and polluted our air and waterways with human-made creations.
But now it is time to repair the environment and our relationship with it, with nanotechnology set to play a vital role in securing the future sustainability of our planet.
Nanomaterials exhibit unexpected properties compared to their bulk counterparts; their high surface-area-to-volume ratio imparts unique physiochemical properties, including versatile functionalities and enhanced reactivity or selectivity.
From saving raw materials, energy and water, to decreasing greenhouse gases and dangerous waste, nanotechnology’s unique attributes can be utilized in various products, procedures and applications that could undoubtedly support environmental and climate protection.
Save the Seas
Oil spills can be catastrophic for oceans, rivers, and the wildlife that reside within it. Conventional methods of clearing spillages are inadequate, and although still in their infancy, nano-based solutions show great promise as an alternative means of tackling the clean-up operation.
Oil spills have devastating effects on our oceans and rivers, with conventional cleanup methods deemed as inadequate. Image Credit: Korelidou Mila/Shutterstock.com
Following the Deepwater Horizon disaster in 2010, researchers from the State University of New York (SUNY) Stony Brook developed a nanogrid of photocatalytic copper tungsten oxide nanoparticles. When activated by sunlight, these nanoparticles break oil down into biodegradable compounds.
"It utilizes the whole solar spectrum and can work in water for a long time,” said Pelagia-Irene Gouma, professor in the Department of Materials Science and Engineering. “Ours is a unique technology. When you shine light on these grids, they begin to work and can be used over and over again."
Nanotechnology-based solutions can contribute to the long-term quality, availability, and viability of water in several ways:
Treatment and remediation
Nanotechnology could yield a new generation of nanomembranes for separation to enable greater water purification and desalinization and better means of removing, reducing, or neutralizing water contaminants. The latter might include zeolites, carbon nanotubes, self-assembled monolayer on mesoporous supports (SAMMS), biopolymers, and single-enzyme nanoparticles, to name a few.
Sensing and Detection
New and enhanced sensors capable of detecting chemical and biological contamination at low concentrations is achievable with nanotechnology. Nanomaterials also make it possible to use photoelectrochemical analysis, integrating light response and chemical sensing for biological and chemical monitoring and negating the need for expensive and sophisticated instruments and operations.
This includes not just ‘traditional’ pollutants, but waterborne infectious diseases. For example, nanotechnology could provide alternative chlorine-free biocides in the form of silver, and titanium dioxide catalysts for photocatalytic disinfection.
Practical water-cleaning applications already in use include utilizing iron nanoparticles to remove organic solvents in groundwater. The nanoparticles disperse through the water and decompose solvents without the need to pump water out of the ground, making the method more effective and less expensive.
Nanotechnology-based solutions can also remove radioactive waste. Titanate nanofibers act as good absorbents to remove radioactive ions such as cesium and iodine from water.
Cleansing the Air
Carbon dioxide (CO2) is perhaps the biggest threat to the environment. The industrial revolution, accompanied by the increasing necessity to burn fossil fuels, has resulted in vast amounts of this greenhouse gas polluting the atmosphere and driving climate change. Consequently, the planet is warming, the polar ice caps are melting, and many low-lying lands are at risk of disappearing altogether.
Utilizing renewable energies is already reducing the amount of CO2 released into the air. However, there is a need to filter CO2 from waste gases for capture and storage if there is no alternative to burning fossil fuels.
Image Credit: Billion Photos/Shutterstock.com
Current methods to separate CO2 from waste gases are expensive, utilize chemicals, and are not competitive enough for large-scale applications. However, membranes constructed from nanomaterials could work in the same way at a fraction of the cost and without additional compounds.
Researchers in Germany have recently fabricated an ultra-thin nanoscale polymer film that filters out CO2 with unmatched results. This high permeance is attributable to the CO2-philic material, which is only a few tens of nanometers thick. Researchers say the material could be used to treat large gas streams under low pressure, such as CO2 capture from flue gases in coal-fired power plants.
Volatile organic compounds (VOCs) also represent a hazard to air quality, contributing to smog and high ozone levels. Japanese researchers discovered a way to remove VOCs – as well as sulfur and nitrogen oxides – from the air at ambient temperatures. They utilized porous manganese oxide with gold nanoparticles grown into it as a catalyst to decompose and remove the offending compounds.
Creating a Delicate Balance
Nanotech offers an enormous opportunity for environmental technologies. There are already many success stories in sensing and monitoring, selective adsorption, and nanomembranes. However, we must be careful to balance the needs of the environment and the activity, selectivity, and stability of the nanotechnologies we choose.
Many of the desirable qualities of nanotechnologies – such as its high performance – result from its high reactivity, caused by its delicate surface and microstructure. As such, we must be careful to avoid damage and degradation of the nanotechnology and further harm to the environment.
References and Further Reading
Sun, H. (2019) Grand Challenges in Environmental Nanotechnology, Frontiers in Nanotechnology [online] https://doi.org/10.3389/fnano.2019.00002 accessed 17 November 2020.
Cimons, M. (2013) Nanogrid, activated by sunlight, breaks down pollutants in water, leaving biodegradable compounds, National Science Foundation [online] https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=129566 accessed 17 November 2020.
Berger, M. (2010) Carbon dioxide capture with nanometric thin-film membranes, Nanowerk [online] https://www.nanowerk.com/spotlight/spotid=18139.php accessed 17 November 2020.
Yave, W. et al. (2010) Nanometric thin film membranes manufactured on square meter scale: ultra-thin films for CO2 capture, Nanotechnology [online] https://iopscience.iop.org/article/10.1088/0957-4484/21/39/395301 accessed 17 November 2020.
Nanowerk, Nanotechnology and the environment, Nanowerk [online] https://www.nanowerk.com/nanotechnology-and-the-environment.php accessed 17 November 2020.
UnderstandingNano, Environmental Nanotechnology, UnderstandingNano [online] https://www.understandingnano.com/environmental-nanotechnology.html accessed 17 November 2020.
Science Daily (2007) New Material Removes Pollutants From Air, Science Daily [online] https://www.sciencedaily.com/releases/2007/03/070330185114.htm accessed 17 November 2020.