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Tag: microplastics

Table Salt in Plastic Recycling

Posted on by dishanth
Table Salt in Plastic Recycling

As far back as 6050 BC, salt has been used for various purposes, including religious offerings and valuable trades. The word “salary” was derived from the word salt because it was highly valued, and production was legally restricted in ancient times, so it was historically used as a method of trade and currency.

Table salt is an important and inexpensive kitchen staple today and is used for various uses, including seasoning, food preservation, food texture, cleaning,  and boiling water. We even use salt in healthcare (such as for cleaning wounds) and for deicing roads and sidewalks. But now table salt is entering a new domain: plastic recycling.

Researchers from Michigan State University are proving that salt in plastic recycling has the properties to outperform much more expensive materials that are being explored to help recycle plastics. The MSU team uses pyrolysis to break down the plastics into a mixture of simpler carbon-based compounds, including gas, liquid oil, and solid wax. Pyrolysis is the process of heating an organic material in the absence of oxygen.

One of the challenges of plastic recycling has always been an undesirable wax byproduct, which accounts for over half of the pyrolysis output. The wax obtained from the pyrolysis of waste plastic is generally regarded as a low-value product that requires further treatment in a refinery for it to be considered valuable as chemicals, diesel, petroleum, and gasoline.

Salt in plastic recycling is used as a catalyst to pyrolyze polyolefins (the family of thermoplastics that include polyethylene and polypropylene); the MSU team produced mostly liquid oil that contains hydrocarbon molecules similar to what is found in diesel fuel, which is not suitable for producing new polymers. There was no undesirable wax; over 50% is generally seen when platinum on carbon or aluminum is used as a catalyst. In this experiment, the result was 86% liquid form and 14% gas.

Using salt in plastic recycling as a catalyst also means the salt can be reused simply by washing the liquid oil with water. The team also found that table salt helped in the pyrolisis of metalized plastic films commonly used in food packaging, such as potato chip bags, which currently aren’t being recycled.

Because table salt is relatively inexpensive, using salt in plastic recycling could drastically reduce the costs associated with these processes. The researchers found that table salt can offer a transformative approach toward an inexpensive (4 cents per kg) and efficient pyrolysis methodology for converting mixed plastics waste to useful hydrocarbon products.

The use of table salt in plastic recycling is a relatively new phenomenon. Traditionally, salt has not been used directly in plastic recycling processes. It has been used indirectly in cleaning and preparing plastic items. It can be used as an abrasive agent to help scrub any residues. It is also used to scrub off adhesive labels from plastic containers.

In recycling facilities, electrostatic separation processes are used to separate different types of plastic based on their electrostatic charges. Salt can affect the conductivity of plastics and help in the separation. Furthermore, the traditional recycling process typically involves mechanical methods such as shredding, melting, and extruding rather than chemical reactions that involve salt. This study can drastically change the way plastic is recycled.

The salt in plastic recycling study from Michigan State University is still in its initial phases. Still, if it catches on, it could be an important movement towards how we recycle plastics and can result in more plastic being recycled and repurposed. It’s fascinating that something so simple and abundant, like table salt, can be used to help tackle one of the world’s most pressing issues.

 

 

 

 

Source   Happy Eco News

Creating Fabric Materials out of Bacteria

Posted on by dishanth
Creating Fabric Materials out of Bacteria

Fast fashion is a sector of the fashion industry whereby business models rely on cheap, rapid and large-scale production of low-quality clothing. Today’s clothing is made of durable and cheap materials such as nylon or polyester. Approximately 60% of fast fashion items are produced with plastic-based fabrics. The microplastics in these garments leach into the waterways with each wash and dry. Half a million tons of these contaminants enter the ocean each year. The fashion industry is also the world’s second-largest water supply consumer. On top of it all, more than 85% of the textiles and clothing purchased will end up in landfill every year.

Modern Synthesis, a biotechnology company, has created a biomaterial made from bacterial fermentation that can be used to create a low-carbon alternative to traditional clothing fabrics. The material the bacteria produces is called nanocellulose, which the company takes from waste feedstocks, including fruit or other agricultural waste. The bacteria will grow on that sugar and naturally produce nanocellulose.

The nanocellulose fibers are very strong and so small that they create strong bonds when they stick to each other. The fibers are eight times stronger than steel and stiffer than Kevlar. With the nanocellulose, the company is creating a material similar to nylon, ripstop fabric (woven fabric made out of nylon) or a coated textile. The material is designed to feel dry and warm, resembling cellulose or paper.

The process of creating the fabric can be adjusted by using different types of thread, some of which can biodegrade, while other threads can be recycled similarly to other cellulose. The project started with the creation of a shoe. Still, thanks to the material’s versatility, the company thinks it can be a good alternative to traditional textiles as it can also be dyed and given different coatings.

They believe their nanocellulose fibers are a significantly more sustainable fabric alternative to cotton, which takes a lot of resources and energy to transform. This material creates significantly fewer emissions than traditional textiles as it only requires transforming waste sugar into usable material. While the material is not yet available for consumer use, the company offers research, development, and consultation services to help brands make better, more environmentally friendly material choices.

As the fashion industry looks for more sustainable ways to make garments, many companies are moving towards using biomaterials to create new textiles. We are now seeing leathers made from fruits and vegetables, sequins made from algae, and so much more. As fast fashion continues to be a problem, the efforts that companies like Modern Synthesis are taking will help the industry reduce its environmental impact while continuing to clothe the world.

 

 

 

 

Source Happy Eco News

Sonic cleanup: using sound to capture ocean microplastics

Posted on by dishanth
Sonic cleanup: using sound to capture ocean microplastics

Researchers in Indonesia have developed an innovative way to remove microplastics from water without the need for expensive filters.

It works, says Dhany Arifianto, an engineer at the Institut Teknologi Sepuluh Nopember in Surabaya, Indonesia, by passing contaminated water through a pipe, while underwater speakers make the pipe vibrate like the sound board of a guitar.

 

We think of sound in terms of what we can hear. But to an engineer, it’s merely a series of pressure waves.

 

Normally, we think of sound in terms of what we hear. But to an engineer, it’s merely a series of pressure waves. When contaminated water passes through the pipe, the water, being liquid, simply transmits the tone. But microplastic particles, being solid, feel the pressure differently, and are driven away from it, Arifianto says.

Surround them by the same tone coming from all sides, and the only place for them to go is the centre of the pipe. When the water emerges from the pipe, this concentrated stream of plastic can then be diverted, while the rest of the water, now cleansed, flows on. “That’s basically the principle of our research,” Arifianto says, “the force created by sound.”

It’s an important development, because microplastics are a growing threat, both to humans and the environment.

Microplastics are tiny fragments of plastic, produced as larger pieces degrade. The US National Oceanic and Atmospheric Administration classifies them as anything smaller than five millimetres in length. “That’s about half the size of a fingernail clipping,” says Charles Moore, founder of Algalita Marine Research and Education, a nonprofit group in Long Beach, California, that is deeply concerned about ocean plastics.

 

Microplastics are a growing threat, both to humans and the environment.

 

Moore is a racing-boat captain who first discovered the Great Pacific Garbage Patch, a massive concentration of plastic detritus trapped by currents, when he was sailing from Hawaii to California after a race and found himself surrounded by a sea of plastic trash.

But the big chunks of plastic Moore stumbled across aren’t the only ones polluting the seas. In the ocean, big pieces of plastic break down into smaller ones, which then break down into microplastics, and from there into even smaller bits. “Microplastics don’t stay micro,” Moore says. “They get nano.”

 

This map shows the location of the Great Pacific Garbage Patch. Credit: NOAA.

 

When that happens, he says, they can lodge in tissues of animals that ingest them (including people). “They don’t just pass through, they get absorbed,” he says. “They pass the blood-brain barrier; they lodge in the placenta. They get into brains and change behavior, because the brain is an electrical organ, and plastics are insulators.”

For example, he says, fish exposed to microplastics don’t go as far or spend as much time looking for food as they normally would.

They also contain xenoestrogens: chemicals that behave like artificial oestrogens. One of these is bisphenol A (BPA), a chemical that is on the State of California’s official list of developmental and reproductive toxicants, based on a review of more than 300 scientific studies of its effect on the female reproductive system.

BPA can also have effects on males – enough that a recent review article in Reproductive Biology and Endocrinology provocatively labeled it an “emerging threat to male fertility.”

Moore adds that it also has behavioral effects, causing male rats to hang out closer to the nest than normal, though it’s not clear if that’s because it is feminising them or simply making them anxious – a factor revealed in other studies.

 

“They get into brains and change behaviour, because the brain is an electrical organ, and plastics are insulators.”

Charles Moore

 

Arifianto’s sound-based cleanup system is still in its infancy, but in lab tests that were scheduled to be presented at the December 2021 meeting of the American Acoustical Society, in Seattle, Washington, his team was able to filter out nylon fragments to an efficiency of up to 99%, and other microplastics to an efficiency of up to 95%. Although, he told Cosmos after he was stranded in Indonesia by US COVID protocols, those results are for fresh water, which is easier to work with than seawater. For seawater, he says, his team has to date only achieved 58% efficiency.

Fifty-eight percent may not sound like a lot – and it wouldn’t be if the goal was to purify drinking water. But Arifianto’s target is more ambitious. He wants to help clean up the ocean, starting in the waters offshore from Indonesia. For that, even 50% efficiency would be an enormous benefit.

To do this, he envisions an array of sonic scrubbers deployed across the narrow straits between his country’s main islands, through which currents circulating between the Pacific and Indian oceans offer perfect locations in which to intercept a lot of microplastics, especially those originating from Indonesia.

It sounds crazy, but the straits aren’t all that wide (the Sunda Strait between Java and Sumatra, for example, is only 24 kilometres across at its narrowest point). And plastics float, meaning that the vast majority of them will be in the top five metres of the water column. To collect them, Arifianto envisions an array of sonic pipes stretching across the straits (except for the shipping channels), moored to the bottom so they stay in place and powered by solar cells, wave energy, or perhaps even the temperature gradient from the top to the bottom of their cables. “There is research [on that] in Japan,” he says of the third option.

 

Arifianto’s target is more ambitious. He wants to help clean up the ocean.

 

The big problem (other than cost), is likely to be noise pollution. “We are generating audible sound,” he says, “so marine life is going to be affected.”

How badly, he doesn’t know, but the sonic level used in his lab experiments is around 50–60 decibels, which is somewhere between the level of a quiet conversation at home and the buzz of conversation in a busy office. Either way, he says, it’s enough to be “quite audible” and “noticeable at quite a distance”. Figuring out how to deal with that will be a priority in future research.

Moore is skeptical of the idea of trying to clean up the ocean. “It’s just not possible,” he says.

What’s ultimately needed, he believes, is to rethink our use of plastics and become “plastic smart”. Or, as his organisation’s website puts it in a banner headline: “First, we change our relationship with plastic. Then, we change the world.”

 

Algalita members protesting against ocean plastic pollution. Credit: Algalita.

 

Arifianto wouldn’t disagree. “I hope I can spread the message that first, we have to stop dumping plastic on the water, whether it’s fresh water or seawater,” he says. “Because it’s going to come back to us in a very harmful way.”

But that doesn’t mean cleanup is useless. “Our work is inspired by the Clean Ocean Project, which put a net in the Pacific to catch ocean garbage.” That was a great idea, he says, but nets can only catch big chunks of plastic. “[So, we thought] how about microplastics?”

Ultimately, Arifianto says, microplastic pollution is a global problem, requiring international efforts. “I hope [our work] is going to reach more people to be aware of the problem and hopefully participate in this global action to clean up.”

 

 

Source Cosmos Magazine