Tag Archives: plastic

Replace plastic with Choetsu which waterproofs paper and degrades safely

It’s good to see research into practical ways of replacing plastic. From a May 13, 2022 news item on ScienceDaily,

For our sake and the environment, there is a considerable amount of research into the reduction of plastic for many and various applications. For the first time, researchers have found a way to imbue relatively sustainable paper materials with some of the useful properties of plastic. This can be done easily, cost effectively, and efficiently. A coating called Choetsu not only waterproofs paper, but also maintains its flexibility and degrades safely as well.

Caption: A classic origami crane made from paper and coated with Choetsu (left) and uncoated (right). When submerged in water, the coated paper crane keeps its shape while the uncoated one quickly saturates with water and starts to disintegrate. Credit: ©2022 Hiroi et al.

A May 13, 2022 University of Tokyo press release (also on EurekAlert), which originated the news item, describes the work in more detail,

It’s hard to escape the fact that plastic materials are by and large detrimental to the environment. You’ve probably seen images of plastic pollution washing up on beaches, spoiling rivers and killing countless animals. Yet the problem often seems completely out of our hands given the ubiquity of plastic materials in everyday life. Professor Zenji Hiroi from the Institute for Solid State Physics at the University of Tokyo and his team explore ways materials science can help, and their recent discovery aims to replace some uses of plastic with something more sustainable: Paper.

“The main problem with plastic materials as I see it is their inability to degrade quickly and safely,” said Hiroi. “There are materials that can degrade safely, such as paper, but obviously paper cannot fulfill the vast range of uses plastic can. However, we’ve found a way to give paper some of the nice properties of plastic, but with none of the detriments. We call it Choetsu, a low-cost biodegradable coating that adds waterproofing and strength to simple paper.”

Choetsu is a combination of materials which, when applied to paper, spontaneously generate a strong and waterproof film when it makes contact with moisture in the air. The coating consists of safe and low-cost chemicals, mostly methyltrimethoxysilane, some isopropyl alcohol, and a small amount of tetraisopropyl titanate. Paper structures, for example food containers, are sprayed with or dipped into this liquid mixture and are dried at room temperature. Once dry, a thin layer of silica containing methyl, a type of alcohol, forms on the cellulose making up the paper, providing the strong and waterproof properties.

Furthermore, reactions that take place during the coating procedure automatically creates a layer of titanium dioxide nanoparticles. These give rise to a dirt- and bacterial-repellent property known as photocatalytic activity, which protects the coated item for an extended period of time. All of the chemicals involved in the coating break down over time into harmless things such as carbon, water and sandlike silicon.

“The technical challenge is complete, and some applications could be realized soon, such as items for consuming, packaging or storing food,” said Hiroi. “We now hope to use this approach on other kinds of materials as well. The liquid composition can be tuned for other materials, and we can create a dirt- and mold-resistant coating that could form onto glass, ceramics and even other plastics to extend their usefulness. Alongside researcher Yoko Iwamiya, who has been working in this field for some time now, and the rest of my team, I hope we can do something truly beneficial for the world.”

Here’s a link to and a citation for the paper,

Photocatalytic Silica–Resin Coating for Environmental Protection of Paper as a Plastic Substitute by Yoko Iwamiya, Daisuke Nishio-Hamane, Kazuhiro Akutsu-Suyama, Hiroshi Arima-Osonoi, Mitsuhiro Shibayama, and Zenji Hiroi. Ind. Eng. Chem. Res. 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.iecr.2c00784 Publication Date: May 13, 2022 © 2022 American Chemical Society

This paper is behind a paywall.

In six hours billions of plastic nanoparticles accumulate in marine organisms

For the sake of comparison, I wish they’d thought to include an image of a giant scallop that hadn’t been used in the research (I have an ‘unplastic’ giant scallop image at the end of this posting),

Caption: These are some of the scallops used as part of the current research. Credit: University of Plymouth

But, they did do this,

A scan showing nanoplastic particles accumulated within the scallop’s gills (GI), kidney (K), gonad (GO), intestine (I), hepatopancreas (HP) and muscle (M). Credit: University of Plymouth [downloaded from https://phys.org/news/2018-12-billions-nanoplastics-accumulate-marine-hours.html]

A December 3, 2018 news item on phys.org announces the research,

A ground-breaking study has shown it takes a matter of hours for billions of minute plastic nanoparticles to become embedded throughout the major organs of a marine organism.

The research, led by the University of Plymouth, examined the uptake of nanoparticles by a commercially important mollusc, the great scallop (Pecten maximus).

After six hours exposure in the laboratory, billions of particles measuring 250nm (around 0.00025mm) had accumulated within the scallop’s intestines.

However, considerably more even smaller particles measuring 20nm (0.00002mm) had become dispersed throughout the body including the kidney, gill, muscle and other organs.

A December 3, 2018 University of Plymouth press release (also on EurekAlert), which originated the news item, adds more detail,

The study is the first to quantify the uptake of nanoparticles at predicted environmentally relevant conditions, with previous research having been conducted at far higher concentrations than scientists believe are found in our oceans.

Dr Maya Al Sid Cheikh, Postdoctoral Research Fellow at the University of Plymouth, led the study. She said: “For this experiment, we needed to develop an entirely novel scientific approach. We made nanoparticles of plastic in our laboratories and incorporated a label so that we could trace the particles in the body of the scallop at environmentally relevant concentrations. The results of the study show for the first time that nanoparticles can be rapidly taken up by a marine organism, and that in just a few hours they become distributed across most of the major organs.”

Professor Richard Thompson OBE, Head of the University’s International Marine Litter Research Unit, added: “This is a ground breaking study, in terms of both the scientific approach and the findings. We only exposed the scallops to nanoparticles for a few hours and, despite them being transferred to clean conditions, traces were still present several weeks later. Understanding the dynamics of nanoparticle uptake and release, as well as their distribution in body tissues, is essential if we are to understand any potential effects on organisms. A key next step will be to use this approach to guide research investigating any potential effects of nanoparticles and in particular to consider the consequences of longer term exposures.”

Accepted for publication in the Environmental Science and Technology journal, the study also involved scientists from the Charles River Laboratories in Elphinstone, Scotland; the Institute Maurice la Montagne in Canada; and Heriot-Watt University.

It was conducted as part of RealRiskNano, a £1.1million project funded by the Natural Environment Research Council (NERC). Led by Heriot-Watt and Plymouth, it is exploring the effects which microscopic plastic particles can have on the marine environment.

In this study, the scallops were exposed to quantities of carbon-radiolabeled nanopolystyrene and after six hours, autoradiography was used to show the number of particles present in organs and tissue.

It was also used to demonstrate that the 20nm particles were no longer detectable after 14 days, whereas 250nm particles took 48 days to disappear.

Ted Henry, Professor of Environmental Toxicology at Heriot-Watt University, said: “Understanding whether plastic particles are absorbed across biological membranes and accumulate within internal organs is critical for assessing the risk these particles pose to both organism and human health. The novel use of radiolabelled plastic particles pioneered in Plymouth provides the most compelling evidence to date on the level of absorption of plastic particles in a marine organism.”

Here’s a link to and a citation for the paper,

Uptake, Whole-Body Distribution, and Depuration of Nanoplastics by the Scallop Pecten maximus at Environmentally Realistic Concentrations by Maya Al-Sid-Cheikh, Steve J. Rowland, Karen Stevenson, Claude Rouleau, Theodore B. Henry, and Richard C. Thompson. Environ. Sci. Technol., Article ASAP DOI: 10.1021/acs.est.8b05266 Publication Date (Web): November 20, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

‘Unplastic giant scallop’

The sea scallop (Placopecten magellanicus) has over 100 blue eyes along the edge of its mantle, with which it senses light intensity. This mollusk has the ability to scoot away from potential danger by flapping the two parts of its shell, like a swimming castenet. Credit: Dann Blackwood, USGS – http://www.sanctuaries.nos.noaa.gov/pgallery/pgstellwagen/living/living_17.html Public Domain

Stunning, isn’t it?

Plastic nanoparticles and brain damage in fish

Researchers in Sweden suggest plastic nanoparticles may cause brain damage in fish according to a Sept. 25, 2017 news item on phys.org,

Calculations have shown that 10 per cent of all plastic produced around the world ultimately ends up in the oceans. As a result, a large majority of global marine debris is in fact plastic waste. Human production of plastics is a well-known environmental concern, but few studies have studied the effects of tiny plastic particles, known as nanoplastic particles.

“Our study is the first to show that nanosized plastic particles can accumulate in fish brains”, says Tommy Cedervall, a chemistry researcher at Lund University.

A Sept. 25, 2017 Lund University press release, which originated the news item, provides more detail about the research,

The Lund University researchers studied how nanoplastics may be transported through different organisms in the aquatic ecosystem, i.e. via algae and animal plankton to larger fish. Tiny plastic particles in the water are eaten by animal plankton, which in turn are eaten by fish.

According to Cedervall, the study includes several interesting results on how plastic of different sizes affects aquatic organisms. Most importantly, it provides evidence that nanoplastic particles can indeed cross the blood-brain barrier in fish and thus accumulate inside fish’s brain tissue.

In addition, the researchers involved in the present study have demonstrated the occurrence of behavioural disorders in fish that are affected by nanoplastics. They eat slower and explore their surroundings less. The researchers believe that these behavioural changes may be linked to brain damage caused by the presence of nanoplastics in the brain.

Another result of the study is that animal plankton die when exposed to nanosized plastic particles, while larger plastic particles do not affect them. Overall, these different effects of nanoplastics may have an impact on the ecosystem as a whole.

“It is important to study how plastics affect ecosystems and that nanoplastic particles likely have a more dangerous impact on aquatic ecosystems than larger pieces of plastics”, says Tommy Cedervall.

However, he does not dare to draw the conclusion that plastic nanoparticles could accumulate in other tissues in fish and thus potentially be transmitted to humans through consumption.

“No, we are not aware of any such studies and are therefore very cautious about commenting on it”, says Tommy Cedervall.

Here’s a link to and a citation for the paper,

Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain by Karin Mattsson, Elyse V. Johnson, Anders Malmendal, Sara Linse, Lars-Anders Hansson & Tommy Cedervall. Scientific Reports 7, Article number: 11452 (2017) doi:10.1038/s41598-017-10813-0 Published online: 13 September 2017

This paper is open access.