Halfway – Violation of rules

The chemist who developed the technique, Vilas Ganpat Pol, of the Argonne National Laboratory in Illinois, has even used the nanotubes as anode material to make lithium-ion batteries. “And it worked fantastically”, he says in New Scientist. Usually graphite or carbon black is used for this purpose. A scientific article about this ‘upcycling’ – converting a waste material into something more valuable – appeared last month in the Journal of Environmental Monitoring.

Polyethylene-based used plastics – best known as plastic bags from the supermarket -need hundreds of years to degrade in atmospheric conditions. These bags can have a severe negative impact and are being produced in escalating quantities; therefore, according to the chemists from Illinois, in addition to conventional recycling facilities, innovative solutions are required. The chemists cooked small pieces of the plastic at 700°C until all chemical bonds broke down. Mixed with cobalt acetate, which serves as a catalyst, the lose carbon atoms then grew into multi-walled carbon nanotubes with cobalt inside.

Promising technique? “Well, I’m not too sure about that,” says Professor Stephen Picken, polymer expert at TU Delft’s faculty of Applied Sciences. According to Picken, there are much more effective ways to recycle plastic. “In Europe we recycle 40 percent of that waste, a part of which we melt and reuse as plastic,” says Picken. Plastic is also shredded and used as a filling material and compressed into objects, like park benches and poles.  About 20 percent disappears in the ground. The rest is burned, which is not waste either, because this creates precious energy.  

But the waste stream is probably worse in many other countries. “Maybe less plastic is recycled in the United States,” says Picken. “I don’t know how it is over there, but still I find it strange that the researchers emphasize the fact that they could solve the waste problem. There is way too much plastic waste compared to the amount of anode material that batteries require.
“Perhaps it is possible to produce high quality carbon nanotubes from plastic. This is certainly a research field on which we have to keep an eye. But I must say that I’m not very impressed by the quality of the nanotubes that these researchers created so far. From the pictures I’ve seen in their publication, they don’t seem very long and straight. I think that if they want to demonstrate the potential of creating useful nanotubes for batteries from plastic, they should start by using pure polyethylene. I think their approach is quite stupid.”

Pickens’ colleague, Professor Andreas Schmidt-Ott, wonders why this research was published in the Journal of Environmental Monitoring and not in a magazine specialized in nanotechnology.
“Maybe the reason is that these kinds of magazines didn’t think the technique is interesting enough,” he says. “The problem with his technique is that it is not a continuous reaction; it’s a batch process. You can only make relatively small amounts at a time. So I don’t see how this can solve the waste problem, even if in the future there is more demand for carbon nanotubes for batteries.”

“Ten years ago, there was a horrible fireworks disaster in the Dutch city of Enschede. An enormous explosion that killed 23 people, injured close to a thousand and destroyed some 400 homes. This disaster made it clear that some things needed to change in the Netherlands. My research focuses on compliance and violation of rules and regulations imposed on chemical companies.

“I accompany the inspectors when they visit 15 companies in the Netherlands. I observe how they work regarding the chemical industry’s occupational safety, health and environmental regulations. The inspectors start by having consultation discussions with representatives of the chemical company they’re visiting. I’d like to know what they discuss. After that they inspect the facility, checking for example if the employees have been properly trained to do their jobs. The inspectors also check to see if there is an evacuation plan in place, and they talk to as many people as possible, to determine if they know the rules regarding their work; for instance, the worker who fills gas tanks must know exactly how to do this.

“Through my research, I hope to determine if a company that has played by the rules for the past ten years has a smaller chance of having accidents occur. And if many minor violations lead to major accidents? I’d also like to know if the assumption is correct that small companies do not know all the rules exactly. If I conclude that most of them do not, then I could work on specific tools aimed at improving this.

“At one of the companies I visited last year, violations were identified. The company did not use special signs to indicate where certain kinds of dangerous liquids should be stored. The risk therefore was that certain chemicals, which should never be put together, would end up being stored next to each other. I’d like to know what that company has done with the feedback the inspectors gave them.

“I like the hands-on approach of my research. I could have focused solely on the data from the inspectors’ reports, but I like to see how the inspectors work and listen to their discussions during inspections, since there is very little scientific insight in this. Recently I’ve been on maternity leave for four months. After that I had to adjust doing my research again, since my PhD study was also put on hold during this period. One of the most fascinating things about my research is that I’ve combined both of my studies, technology and criminology. I hope the multidisciplinary aspect of my research will lead to new insights in safety science and criminology.”