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Recent advancements in the field of thin film technologies have extended their application well beyond those within the semiconductor industry. In fact, several research studies have explored the potential use of thin films to tackle some of the most important issues that currently plague our environment.
While this research has shown promising results, it also critical to examine the potential effects that thin film production methods can pose to the environment.
Addressing Heavy Metal Contamination
A recent 2018 study investigated how the incorporation of thin films into two different bioremediation tools successfully immobilized bacterial cells in an effort to remove arsenic and uranium contaminants from the environment.
Both arsenic and uranium are toxic elements that have the potential to cause irreversible ecological damage when released into the environment. In particular, inorganic arsenic can inhibit growth, photosynthesis, and reproduction rates of various plant and animal species. Similarly, uranium contamination, which typically occurs as a result of mining activity, can also disrupt local geology, as well as affecting water quantity and quality.
Thin Film Bioremediation Tools
The main mechanism behind bioremediation tools involves chelation, compartmentalization, exclusion, and immobilization of the contaminants of interest. To this end, an arsenic biofilter was developed by genetically modifying an arsenic-resistant strain of bacteria known as Ochrobactrum trittici SCII24T.
Since these cells have been shown to accumulate high levels of arsenite, they were immobilized onto a poly (tetrafluoreoethylene) (PTFE) thin films to create the arsenic biofilter. The researchers of this study found that the bacterial cells immobilized on the surface of the thin film successfully retained their ability to accumulate arsenite.
To address uranium contamination, a similar biofilter was constructed by instead placing Rhodanobacter A261 cells onto PTFE thin films. In this study, the biofilter was found to immobilize uranium contaminants present within a wastewater treatment plant that is directly connected to a uranium mine in Portugal.
Both of the bio-PTFE thin films discussed here demonstrated their ability to accumulate two highly toxic compounds that are common environmental and human health contaminants.
Thin Films and Renewable Energy
As the global population is becoming increasingly aware of our role in preserving the integrity of the planet, the push towards using renewable energy sources has escalated as well. In order to ensure that sustainable energy sources, such as solar photovoltaic cells, will meet the needs of most people around the world, it is imperative to maintain the lowest possible production costs associated with developing these technologies.
Researchers have concluded that as the most inexpensive technology capable of converting sunlight into energy, thin films appear to also reduce the cost of solar grid electricity. This type of significant reduction in solar panel costs can therefore increase the availability of these alternative energy sources to a wider spectrum of consumers than ever before.
Environmental Impact of Thin Films
Various research initiatives have examined the environmental impact associated with the manufacturing, use, and disposal of thin films. In particular, these studies have focused on the energy requirements and availability of resources required to develop and discard thin films, the potential emissions of toxic materials, as well as the occupational health and safety of workers involved in these processes.
For example, a recent study compared the life-cycle emissions of photovoltaic production sites to those associated with the production of cadmium tellurium (CdTe) thin film photovoltaic systems.
The researchers found that safely encapsulating heavy metals like cadmium during the production processes prevents up to 99.9% of cadmium from being released into the environment. Since many power plants that currently produce photovoltaic cells are powered by the burning of fossil fuels, the cadmium removal efficiency of these plants is reduced to approximately 98.6%.
Sources and Further Reading
- “What are the effects of arsenic on the environment?” – GreenFacts
- Piedade, A. P., Romeu, F., Branco, R., & Morais, P. V. (2018). Thin Films for Medical and Environmental Applications. IntechOpen DOI: 10.5772/intechopen.80021.
- Fthenakis, V. (2009). Sustainability of photovoltaics: The case for thin-film solar cells. Renewable & Sustainable Energy Reviews 13(9); 2746-2750. DOI: 10.1016/j.rser.2009.05.001.