How to Clean up Microplastics? New Technologies to Meet the Environmental Challenge
Ferrofluids, plastic-metabolizing bacteria or plant-based filters are some of the proposals.
Microplastics have become a ubiquitous threat. They can be found on the highest peaks of the planet, at the bottom of the sea, and even in the body of the reader of this article. As they degrade, plastics do not disappear but disintegrate into smaller and smaller fragments that circulate throughout the ecosystem. Moreover, they can have harmful consequences for the health of living beings, especially in the case of marine animals. The very fact that they are such tiny particles, up to one hundred and fifty times smaller than a human hair, is one of the great challenges when it comes to removing them. Until now, special membranes and other expensive technologies were the only choice, but in recent years new strategies have begun to emerge.
The irresistible power of ferrofluids
His name is Fionn Ferreira and in 2019 he won first prize at the Google Science Fair for his innovative system for cleaning microplastics. This 20-year-old Irishman has put forward a proposal based on the use of ferrofluids. His filter uses an oily ferrofluid and oxide particles, as the microplastics tend to couple with metal particles. Once this process has taken place, the ferrofluid attracts the plastic particles paired with the metal. The technology has demonstrated 88% efficiency in water purification. The aim is that the new filter can be integrated into existing equipment, from water purifiers to domestic washing machines, one of the major culprits in the emission of microplastics when cleaning synthetic clothes. One of Ferreira's most promising strategies is the installation of these filters in the cooling systems of boats. Motorboats use seawater to cool their equipment and then return it to the sea. The idea is that, in the future, ships will become floating filtering stations that help eliminate microplastics.
Bacteria could be the key
If there is anything more ubiquitous than microplastics, it is bacteria. The metabolic capabilities of these microorganisms already play a key role in water purification and even play a leading role in innovative renewable energies. They can metabolize sulfuric acid and, of course, also polymers. Some of them were already capable of metabolizing lignin or wax, but others have evolved to feed on plastics. Researchers are now exploring the possibility of stimulating this ability to use them as cleaners in ecosystems. The approach is based on locating the most efficient bacteria in this sense to enable treatments that degrade plastics, both in landfills and in seawater. This bioengineering technique, which is still in its early stages, could contribute to eliminating part of the millions of tons of plastic that end up in the seas each year.
Next generation filters
In addition to bacteria, there is the possibility of using plants as an alternative for filtering microplastics. The VTT Technical Research Centre in Finland has developed a new nanocellulose membrane capable of trapping the tiniest plastic particles. The colloidal and porous structures of this filter trap microplastics without the need for chemical agents or mechanical action. As with Ferreira's proposal, there is the possibility of integrating it into washing machines to prevent microplastics from reaching wastewater and, ultimately, the sea.
As always, the best strategy is to reduce the production of plastics. But in the meantime, these new technologies can help combat this invisible and ubiquitous enemy.
Source: The Guardian