Sometimes, when you try to solve one problem, you create another. A famous example is the introduction of the cane toad into Australia from Hawaii in 1935. The toads were introduced as a means of eliminating a beetle species that ravaged sugar cane crops; but now, almost a century later, Western Australia is inundated with these venomous, eco-system-meddling creatures.

In a similar spirit, disposable face masks could help tackle one urgent problem while creating another. According to researchers at Swansea University, nanoplastics and other potentially harmful pollutants have been found in many disposable face masks, including the ones some use to ward off Covid-19.

After submerging various types of common disposable face masks in water, the scientists observed the release of high levels of pollutants including lead, antimony, copper, and plastic fibres. Worryingly, they found significant levels of pollutants from all the masks tested.

Microscope image of microfibres released from children's mask: the colourful fibres are from the cartoon patterns | Credit: Swansea University

Obviously, millions have been wearing single-use masks around the world to protect against the Covid-19 pandemic, but the release of potentially harmful substances into the natural environment and water supply could have far-reaching consequences for all of us.

‘The production of disposable plastic face masks (DPFs) in China alone has reached approximately 200 million a day in a global effort to tackle the spread of the new SARS-CoV-2 virus,’ says project lead Dr Sarper Sarp, whose team’s work has been published on Science Direct. ‘However, improper and unregulated disposal of these DPFs is a plastic pollution problem we are already facing and will only continue to intensify.

The presence of potentially toxic pollutants in some face masks could pose health and environmental risks.

‘There is a concerning amount of evidence that suggests that DPFs waste can potentially have a substantial environmental impact by releasing pollutants simply by exposing them to water. Many of the toxic pollutants found in our research have bio-accumulative properties when released into the environment and our findings show that DPFs could be one of the main sources of these environmental contaminants during and after the Covid-19 pandemic.’

The Swansea scientists say stricter regulations must be enforced during manufacturing and disposal of single-use masks, and more work must be done to understand the effect of particle leaching on public health and on the environment. Another area they believe warrants investigation is the amount of particles inhaled by those wearing these masks.

‘This is a significant concern,’ adds Sarp, ‘especially for health care professionals, key workers, and children who are required to wear masks for large proportions of the working or school day.’

In this new series, members of the SCI Mid-Career group offer advice on career management and how to overcome career challenges.

In our latest interview, we hear from David Freeman, Research & Technology Director for Croda’s Energy Technologies business.

Please tell us about yourself and your career journey.
After a PhD in organic chemistry, I started my career with ICI Paints in Slough in 1998, working in a product development role. Within a couple of years, I moved to another ICI business, Uniqema, and had various technical roles around the chemical synthesis or process development of new materials.

These early roles – and the people I worked with during this time – had a big impact on me in terms of ways of working and how to deal with people. I subsequently joined Croda in 2006 and have since had further technical roles – initially around the technical management of Synthesis programmes in Croda, then technical management of Applications programmes, and finally on to my current role of R&T Director for Croda’s Energy Technologies business.

This last transition was probably the most interesting and challenging as it forced me to think much more strategically about the “what” rather than the “how” and what leadership versus management was all about. I see this area as being hugely important to the Mid-Career group.

What are your keys to managing your career at this stage?
Development remains really important to me from a personal perspective. I have always driven my own development, but been well supported by the organisations I’ve worked for: both by technical management teams and HR teams. At the mid-careers stage, there are lots of important things to think about but I consider the following to be key:

• (i) Self-understanding and feedback: make sure you understand your strengths and weaknesses and how these manifest themselves with colleagues by seeking open and honest feedback
• (ii) Get external perspectives on your areas of interest and expertise. This for me is really key in challenging thinking and bringing new ways of working and innovation to your role
• (iii) Understand the big picture: make sure you’re clear about what’s going on in the world at a high level and the part you and your organisation have to play in meeting these challenges.

What challenges are there around mid-career support?
I feel very fortunate to have worked for organisations where development is extremely important – support is always on hand when I need it. The key challenge is a personal one and it’s about making enough time to focus on the right development areas. We are all busy but if we want to develop ourselves enough, then we will find that time!

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We are increasingly conscious of the need to recycle waste products, but it is never quite so easy as rinsing and sorting your waste into the appropriate bins, especially when it comes to plastic.

Despite our best intentions, only around 16% of plastic is recycled into new products — and, worse, plastics tend to be recycled into low quality materials because transformation into high-value chemicals requires substantial amounts of energy, meaning the choices are either downcycling or prohibitively difficult. The majority of single-use plastics end up in landfills or abandoned in the environment.

This is a particular problem when it comes to polyolefins such as polyethylene (PE) and polypropylene (PP), which use cheap and readily available raw materials. Approximately 380 million tonnes of plastics are generated annually around the world and it is estimated that, by 2050, that figure will be 1.1 billion tonnes. Currently, 57% of this total are polyolefins.

Why are polyolefins an issue? The strong sp3 carbon–carbon bonds (essentially long, straight chains of carbon and hydrogen atoms) that make them useful as a material also make them particularly difficult to degrade and reuse without intensive, high energy procedures or strong chemicals. More than most plastics, downcycling or landfill disposal tend to be the main end-of-life options for polyolefins.

Polyethylene is used to make plastic bags and packaging.

Now, however, a team of scientists from MIT, led by Yuriy Román-Leshkov, believe they may have made a significant step towards solving this problem.

Previous research has demonstrated that noble metals, such as zirconium, platinum, and ruthenium can help split apart short, simple hydrocarbon chains as well as more complicated, but plant-based lignin molecules, in processes with much lower temperatures and energy.

So the team looked at using the same approach for the long hydrocarbon chains in polyolefins, aiming to disintegrate the plastics into usable chemicals and natural gas. It worked.

First, they used ruthenium-carbon nanoparticles to convert more than 90% of the hydrocarbons into shorter compounds at 200 Celsius (previously, temperatures of 430–760 Celsius were required).

Next, they tested their new method on commercially available, more complex polyolefins without pre-treatment (an energy intensive requirement). Not only were the samples completely broken down into gaseous and liquid products, the end product could be selected by tuning the reaction, yielding either natural gas or a combination of natural gas and liquid alkanes (both highly desirable) as preferred.

Polypropylene is used in bottle caps, houseware, and other packaging and consumer products.

The researchers believe that an industrial scale use of their method could eventually help reduce the volume of post-consumer waste in landfills by recycling plastics to desirable, highly valuable alkanes — but, of course, it's not that simple. The team says that more research into the effects of moisture and contaminants in the process is required, as well as product removal strategies to decrease the formation of light alkanes which will be critical for the industrialisation of this reaction.

However, they believe the path they're on could lead to affordable upcycling technology that would better integrate polyolefins into the global economy and incentivise the removal of waste plastics from landfill and the environment.

More about the study can be read here:
https://pubs.acs.org/doi/full/10.1021/jacsau.0c00041