Plastic waste is one of the scourges of the modern world, being generated via every industry from electronics to packaging and vehicles. Once discarded, plastic chokes our landfills and oceans for centuries, and when one considers that humans produce almost 300 million tons of plastic each year, the extent of the problem becomes all too clear.
A new discovery made by researchers at North Dakota State University, Fargo, could help to solve this serious environmental issue, however, as they believe they have paved the way for the creation of a new type of plastic that can be broken down into molecules when exposed to a specific type of light. What is even better news is that once the plastic has broken down, it can be recycled to form new plastic products.
The team of researchers, from the Center for Sustainable Materials Science at NDSU also focused on using biomass, a renewable resource using oilseed from agricultural crops, cellulose, lignin and sucrose to generate the building blocks of molecules that are made into polymers to create the plastics, in order to lessen dependency on fossil fuels. NDSU, in association with the North Dakota Experimental Program to Stimulate Competitive Research (ND EPSCoR), established the Center for Sustainable Materials Science to develop a program for the preparation of polymers and composites using biomass.
“Real sustainability involves breaking it back into the building blocks. We have shown that we can break it down into the building blocks and re-make the polymer,” said one of the team, Dr. Mukund Sibi, a university distinguished professor.
In their proof of concept experiment, the group used fructose, found commonly in fruit, to create a solution of molecules, which was then converted to a plastic (polymer). By exposing the plastic to ultraviolet light at 350 nanometers for three hours, researchers degraded the plastic, reducing it back to the soluble building block molecules from which it began. Plastics generally degrade very slowly, potentially leaching chemicals into the environment or creating toxins in the air when burned.
“This cradle-to-cradle approach to create a plastic which can be degraded easily offers scientific potential for eventual products that could lessen dependence on fossil fuels and decrease the amount of raw materials needed,” said Dr. Webster.
“Our strategy has the potential to build novel materials from biomass that are degradable with light after usage, mitigating the stress of unwanted chemicals in our environment. Studies to address these aspects are currently underway in our laboratories,” said Dr. Sivaguru Jayaraman.
Dr. Sibi’s lab makes monomers and biobased triggers; Dr. Siva’s group specializes in photochemical sciences and photo degradation; and Dr. Webster’s team works in polymer chemistry.
“It is the teamwork which allows us to do this kind of work. We need everyone’s expertise to solve this issue,” said Sibi.
The researchers say further study is needed to evaluate the durability and strength of potential plastics derived from biomass before potential product commercialization could occur. “What is the best trigger to use to break them down? What is the best monomer to use? What is the best polymer we can make?” said Sibi.
In the next two years, the group will examine how their process might work with plastics used in cars and electronics, as well as in other items.
This innovation could be a major development to reduce the amount of non-degradable waste that currently clutters and suffocates our environment, yet there has been some indication that plastic waste is mysteriously disappearing of its own accord.
Due to the vast production of plastic waste each year, there should be millions of tons floating in the world’s oceans, yet a new study has discovered that 99% of this plastic waste seems to have vanished inexplicably. The only explanation that seems to make sense is a very disturbing one: that fish could be eating the waste.
If this is true then “there is potential for this plastic to enter the global ocean food web,” says Carlos Duarte, an oceanographer at the University of Western Australia, Crawley. “And we are part of this food web.”
Based on industry figures, the amount of plastic waste that should be present in our oceans was estimated to be millions of tons, yet the results of the research project, which used four ships to trawl for plastic waste across all five major ocean gyres in 2010 and 2011, indicated that a mere 40,000 tons of plastic remained.
“We can’t account for 99% of the plastic that we have in the ocean,” says Duarte, the team’s leader.
The results, which were published in the Proceedings of the National Academy of Sciences, suggest that whilst plastic does not fully degrade, it is eventually broken down by waves and solar radiation into small particles that fish may mistake for food.
The results of the study have confirmed views already held by other academics in the field.
“Yes, animals are eating it,” says oceanographer Peter Davison of the Farallon Institute for Advanced Ecosystem Research in Petaluma, California, who was not involved in the study. “That much is indisputable.”
If the plastic is entering the human food chain, the consequences could be profound: the toxic waste could be working its way up into human staples such as tuna and swordfish, although it is just as possible, says Davison, that the waste “may dissolve back into the water … or for all we know they’re puking [the plastic] or pooping it out, and there’s no long-term damage. We don’t know.”
Kara Law, a physical oceanographer at the Sea Education Association in Woods Hole, Massachusetts, says it would be impossible to estimate how much plastic is being consumed by marine life, and that “we’re desperately in need of a better estimate of how much plastic is entering the ocean annually.”
If fish are not consuming the waste, then other likely explanations are that it is being degraded into tiny pieces and washed ashore, or that tiny organisms are sticking to and growing on the plastic, then dragging it beneath the ocean’s surface.
These are the best-case scenarios but in truth, at this stage, nobody really knows. “I don’t think we can conceive of the worst-case scenario, quite frankly," said Law." We really don’t know what this plastic is doing.”
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