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NNadir

(33,368 posts)
Sun Sep 19, 2021, 09:12 AM Sep 2021

Addressing Color and the Ongoing Failure of PET Plastic Recycling.

The paper I'll discuss in this post is this one: Simple But Tricky: Investigations of Terephthalic Acid Purity Obtained from Mixed PET Waste (Lelia Cosimbescu, Daniel R. Merkel, Jens Darsell, and Gayaneh Petrossian, Industrial & Engineering Chemistry Research 2021 60 (35), 12792-12797). The scientists who authored this paper all work at the Pacific Northwest National Laboratory, just outside of the Hanford Nuclear Complex. (Much of the work at PNNL is directed at handling and treating radioactive materials from the nuclear weapons manufacturing industry that operated in the 20th century. This industry left many of these radioactive materials in poorly contained conditions. This paper is not about radioactivity though; it's about a much worse problem, as it is on a much more massive scale, and more widely distributed, plastic contamination.)

Although this is fine scientific work, I can't say I endorse the scheme I'll briefly discuss related to this paper. My preferred technology for dealing with plastic pollution, including but no limited to microplastics and plastic waste allegedly recycled is steam or supercritical water reforming or dry reforming in a reverse Allam cycle. Thus, my chief interest in posting reference to this paper is with the statistics therein and the elucidation of an issue about which I've not thought much, if at all, the issue of color as a problem in the widely held belief that we can, and even worse, do recycle plastics.

I will bold the sections of the introduction to the paper, which follows, to highlight the interesting statistics and information.

Polyethylene terephthalate (PET) is a thermoplastic polyester mainly used in textiles and single-use packaging due to its physicochemical properties such as good thermal and chemical resistance, mechanical properties, durability, and lightweight. The majority of the world’s PET is utilized for synthetic fiber production (over 60%), while bottle production accounts for about 30% of global demand.(1) Mechanical recycling of PET is cost-efficient and already implemented in plants with capacities of 5000–20,000 tons/year. However, chemical contaminants and degradation products generated during first processing and usage represent the main source of quality depreciation and rise of impurities in the recycling stream. Recycled materials are increasingly introduced into manufacturing processes, but require efficient sorting, separation, and cleaning processes for production of high-quality recycled polyester. As a result, recycling rates for colored bottles and films are significantly lower due to the broad range of colors, additives, multilayer structure, labels, and adhesives.(2) Just 2% of plastic packaging, which is largely composed of PET, is recycled annually into products of similar quality.(3) Fiber-grade PET, often called “polyester”, for textile material production has a molecular weight of 15–20 kg mol–1 and intrinsic viscosity between 0.4 and 0.75 dL/g, while bottle-grade PET has a higher molecular weight (>20 kg/mol) with an intrinsic viscosity above 0.95 dL/g. The different grades of PET cannot be blended because their properties are incompatible in the respective processing methods and/or give poor properties in the recycled product.(4) Therefore, often, the bottle-grade PET which cannot undergo mechanical processing for recycling due to color or mixed media PET is mainly disposed in landfills or incinerated. Mechanical recycling of PET in the United States converts only about two-thirds of the collected bottles to clean flake with the remaining one-third (531 million lbs) being landfilled.(5) Chemical recycling of PET circumvents this barrier and provides pathways to not only monomers but feedstock for other chemical products and high-performance polymers such as polyaramids.(6)


The added italics are also mine.

We all dutifully put our plastics into the recycling bins at home, at work, and in many commercial establishments, without thinking what happens to them afterwards. Much of the plastic nonetheless, ends up in landfills, and some certainly escapes into bodies of water, into land, and as is increasingly clear, into the flesh of living things including, but hardly limited to, humans.

The authors of this paper have proposed a method of plastic recycling by heating colored waste plastics in solvents, investigating ethanol and ethylene glycol - generally made from dangerous fossil fuels - for the process both in the presence of strong base, sodium hydroxide.

The conditions utilized are shown in this table from the text:



Some pictures from the text:



The caption:

Figure 1. Hydrolysis of mixed PET waste to obtain pure TPA in ethylene glycol/water: (a) mixed PET starting material; (b) reaction after 30 min; (c) reaction after 6 h; (d) water added to the clearing point to dissolve TPA salt; (e) filtration products of non-PET waste and unreacted PET; (f) basic mother liquor of TPA sodium salt after filtration; (g) solid TPA in aqueous solution at pH 4; and (h) isolated TPA via vacuum filtration. This example illustrates TPA3.





The caption:

Figure 2. Hydrolysis of mixed PET waste to obtain pure TPA in ethanol/water: (a) reaction after 2 h; (b) waste impurities and PET removed from mother liquor; (c) mother liquor during acidification with HCl; and (d) solid obtained by filtration. This example illustrates TPA4.




The caption:

Figure 3. DSC of TPA2 (a), TPA3 (b), TPA4 (c), and a commercial TPA denoted as TPA std (d) at a 5 °C heating/cooling rate.


DSC is differential scanning calorimetry, a method relying on the how flow, absorption, or release of heat takes place as a material is heated.



The caption:

Figure 4. Powder XRD pattern for TPA2, TPA3, TPA4, and TPA std (commercial material). Also shown are expected peak locations (as + signs) for the TPA tetragonal phase from the XRD reference file (ICDD PDF card 00-031-1916).


XRD is X-Ray Diffraction of the samples as compared to files in a database comprising standards.

From the conclusion:

Both ethylene glycol and ethanol solvents in an aqueous base are efficient at depolymerizing mixed PET. The concentration of NaOH in water does not appear to affect the reaction if it is at least 20% (compare entries 4 and 5 in Table 1). While the ethylene glycol system appears to be less efficient in terms of temperature (110 °C vs 80 °C) and the time required to achieve the same conversion as the ethanol system (6 h vs 2 h), it provides an advantage in the recovery of the organic solvent if desired. Ethylene glycol can be easily separated from the mixture via distillation of water, whereas ethanol will azeotrope with water and hinder such separation. Ethylene glycol when used with mixed PET appeared to generate a nearly white solid, probably less prone to dissolve pigments in the by-waste, while ethanol produced a much more pink colored product. For reasons not yet understood, the ethylene glycol products appear to display a melting point transition above 280 °C versus the ethanol product, which did not...


Again, this is not in my opinion, the ideal approach to dealing with this problem. To my thinking, the entire petrochemical industry, including polymers but clearly not limited to them, should begin and end with carbon monoxide/dioxide and hydrogen as starting materials. I have convinced myself this is feasible, not easy, perhaps not really popular, but feasible.

The Hanford site, outside the PNNL site where this work was conducted, was constructed and operated under paranoid conditions of perceived emergency beginning in the Second World War and proceeding through the "cold war," to isolate nearly isotopically pure (Pu-239) plutonium. The conditions were primitive and sloppy, but need not be so any longer if we want - and we should want - useful plutonium. Much of the plutonium isolated in the 20th century at Hanford remains in nuclear weapons which should, in the mind of sane people, remain useless. It is available however, in a sane world, for use to generate heat, heat being the key intermediate for producing carbon monoxide/dioxide and hydrogen.

Have a pleasant Sunday.
7 replies = new reply since forum marked as read
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Addressing Color and the Ongoing Failure of PET Plastic Recycling. (Original Post) NNadir Sep 2021 OP
Yeah Nuclear Energy - Boo PET plastics WA-03 Democrat Sep 2021 #1
Your statement shows an extremely limited knowledge of Hanford, and nuclear science in general. NNadir Sep 2021 #2
I just wanted to know how to clean it up WA-03 Democrat Sep 2021 #3
My joke stated that a JOURNALIST cannot get a degree in journalism if he or she passed a SCIENCE... NNadir Sep 2021 #4
Kindly point me WA-03 Democrat Sep 2021 #5
Um, you'd have to be pretty high to think I can compress 30 years of study into a blog post for... NNadir Sep 2021 #6
Thank you WA-03 Democrat Sep 2021 #7

WA-03 Democrat

(3,017 posts)
1. Yeah Nuclear Energy - Boo PET plastics
Sun Sep 19, 2021, 11:52 AM
Sep 2021

So happy you referenced and mentioned Hanford.

The damage to Hanford is unrealizable and not deemed not repairable (24,000 years for Plutonium to come harmless). The damage of Hanford, WA to PET is laughable. Half of all the waste from our Atom bombs are right here in one place on the Columbia River.

[link:https://www.nbcnews.com/news/us-news/welcome-most-toxic-place-america-n689141|

[link:

|

][link:https://www.king5.com/article/news/investigations/hanford-nuclear-site-washington-state-tank-farms-workers-sickened-investigation/281-48a540ea-1fa5-4de9-8ab7-b1dc9db6e5c8|

][link:https://www.businessinsider.com/hanford-nuclear-site-photos-toxic-waste-2019-9|

I would be extremely interested in any ideas to clean up Hanford.




NNadir

(33,368 posts)
2. Your statement shows an extremely limited knowledge of Hanford, and nuclear science in general.
Sun Sep 19, 2021, 01:55 PM
Sep 2021

You reference stuff written by a journalist and a comedian, which calls up my often repeated half serious joke that one cannot get a degree in journalism if one has passed a college level science course with a grade of C or better.

I note that it was journalists who blew up a statement by a shithead FBI Director, James Comey, that he was investigating Hillary Clinton's emails, to allow a perverted ignorant corrupt racist the latitude to spend four years

You open your statement with a parenthetical that reads as follows:

(24,000 years for Plutonium to come harmless).


This is a nonsense statement.

The half-life of plutonium is 24,000 years, meaning that if one had a kg of the stuff, one would still have 500 grams of it after 24,000 years. In an educated population, most people would understand this, but regrettably, most people don't understand science and react it to it with fear and ignorance, similar to the fear and ignorance connected with vaccines that is now also killing people, although anti-nuke rhetoric kills people as well, as evidenced by the report I will reference and quote below from one of the most prestigious medical journals in the world, Lancet.

Plutonium decays into Uranium-235, which occurs naturally in vast quantities not only in granite, ores, and seawater, but also in the Earth's core, where it drives most of the world's internal heat in concert with U-238, thorium-232, and the decay products, which also occur naturally, and are highly radioactive. If Uranium-235 did not occur naturally, it would have never been possible to build a nuclear reactor. But it does exist, and one can reduce the number of radioactive elements it produces in its decay series by fissioning it.

Now, you may think that I know nothing about Hanford other than what the comedian John Oliver and a stupid journalist at NBC News with a poor education calls the "most toxic place in America."

By contrast to your source of information, I have routine familiarity with oodles of scientific publications on the subject of the Hanford tanks, processing at Hanford, etc.

I know the chemistry of plutonium far better than either John Oliver, far better than some asshole at NBC News. Tell me, given this alleged toxicity, what's the death toll in Richland been as a result? Is the city still there? Are people dropping like flies from this presumed toxicity?

If the Columbia River is so badly contaminated, how is that Portland Oregon, at the mouth of that river which is being destroyed far more by Climate Change resulting from not using nuclear energy to its full potential, has the highest life expectancy in Oregon?

I have written in this space about the geochemistry of plutonium at the Nevada National Security Site (which, therein I dub the Nevada National Insecurity site), a site whose plutonium content dwarfs that of Hanford. In this same post, I discuss in considerable detail, a number of issues and events at the Hanford site, parenthetically.

828 Underground Nuclear Tests, Plutonium Migration in Nevada, Dunning, Kruger, Strawmen, and Tunnels

The document is filled with oodles of references to the scientific literature, including many relevant to the properties of plutonium at Hanford, as well as a significant discussion of technetium at Hanford.

If I lived in Washington - I don't - and I was losing sleep because I'm scared shitless by stuff John Oliver and scientifically illiterate journalists say, I might try to set my mind at ease by opening a science book and looking at something called "facts." Facts matter. But I understand that most people would rather pay considerable attention to nonsense information rather than engage in serious inquiry to important issues, to be lathered into panic over nonissues. Hence, the importance of "...her emails," and "...Saddam Hussein's weapons of mass destruction..." etc., etc., etc. ad nauseum.

The practice of critical thinking on this planet is nearly dead, hence the huge fires that tore through the Northwest Pacific Coast, as high as British Columbia this summer, while experiencing temperatures of greater than 40C.

Nuclear Energy saves lives: Prevented Mortality and Greenhouse Gas Emissions from Historical and Projected Nuclear Power (Pushker A. Kharecha* and James E. Hansen Environ. Sci. Technol., 2013, 47 (9), pp 4889–4895)

While people whine about Hanford insipidly (such whining motivated my post linked above about the Nevada Site), air pollution kills a human being on this planet every five seconds, at a rate of more than 18,000 people per day, more people than Covid killed worldwide on its worst day.

To wit, the Lancet reference and an excerpt:

It is here: Global burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019 (Lancet Volume 396, Issue 10258, 17–23 October 2020, Pages 1223-1249). This study is a huge undertaking and the list of authors from around the world is rather long. These studies are always open sourced; and I invite people who want to carry on about Fukushima to open it and search the word "radiation." It appears once. Radon, a side product brought to the surface by fracking while we all wait for the grand so called "renewable energy" nirvana that did not come, is not here and won't come, appears however: Household radon, from the decay of natural uranium, which has been cycling through the environment ever since oxygen appeared in the Earth's atmosphere.

Here is what it says about air pollution deaths in the 2019 Global Burden of Disease Survey, if one is too busy to open it oneself because one is too busy carrying on about Hanford:

The top five risks for attributable deaths for females were high SBP (5·25 million [95% UI 4·49–6·00] deaths, or 20·3% [17·5–22·9] of all female deaths in 2019), dietary risks (3·48 million [2·78–4·37] deaths, or 13·5% [10·8–16·7] of all female deaths in 2019), high FPG (3·09 million [2·40–3·98] deaths, or 11·9% [9·4–15·3] of all female deaths in 2019), air pollution (2·92 million [2·53–3·33] deaths or 11·3% [10·0–12·6] of all female deaths in 2019), and high BMI (2·54 million [1·68–3·56] deaths or 9·8% [6·5–13·7] of all female deaths in 2019). For males, the top five risks differed slightly. In 2019, the leading Level 2 risk factor for attributable deaths globally in males was tobacco (smoked, second-hand, and chewing), which accounted for 6·56 million (95% UI 6·02–7·10) deaths (21·4% [20·5–22·3] of all male deaths in 2019), followed by high SBP, which accounted for 5·60 million (4·90–6·29) deaths (18·2% [16·2–20·1] of all male deaths in 2019). The third largest Level 2 risk factor for attributable deaths among males in 2019 was dietary risks (4·47 million [3·65–5·45] deaths, or 14·6% [12·0–17·6] of all male deaths in 2019) followed by air pollution (ambient particulate matter and ambient ozone pollution, accounting for 3·75 million [3·31–4·24] deaths (12·2% [11·0–13·4] of all male deaths in 2019), and then high FPG (3·14 million [2·70–4·34] deaths, or 11·1% [8·9–14·1] of all male deaths in 2019).


Let me know if you can find in this comprehensive publication, which is open sourced and can be read by anyone, and is written by a vast consortium including scientists, physicians and health experts around the world, any reference to what the NBC twit calls "the most toxic place in America."

WA-03 Democrat

(3,017 posts)
3. I just wanted to know how to clean it up
Sun Sep 19, 2021, 04:23 PM
Sep 2021

I left the half life in so you could or would correct it. Yes, 1 gram of plutonium takes 48,000 to be harmless. Critical thing skills would know it’s exactly half or just coincidence?

2021 + 48,000 = 50,021 AD

Scientists have held that Hanford is safe but there is no way to manage nuclear waste. In human terms in is not fixable.

The NBC “twit” you referenced received the following:
1) Obtained BA at Bard at the age of 15
2) JD Yale Law School
3) Passed NY State Bar Exam
4) Rhodes Scholar
5) PhD from Oxford

Ronan Farrow was that “NBC twit” and he may be many things but calling him stupid seems, well stupid. Where are your facts of his foolishness to support your assertion!?

The fact is all of the great energy science has brought us to here, there no way to clean it up and it is killing us. Petroleum or nuclear it’s the same result. It will all kill us and there is nothing we can do about it. Our planet that is nearing the end of being able to support our species and the rest of life as we know it. Science doesn’t get everything right and never will. It’s is imperfect like us all. Styrofoam is a speck of sand on the beach of issues.

NNadir

(33,368 posts)
4. My joke stated that a JOURNALIST cannot get a degree in journalism if he or she passed a SCIENCE...
Sun Sep 19, 2021, 05:33 PM
Sep 2021

course with a grade of C or better.

Ronan Farrow is NOT a scientist; he has no background in inorganic chemistry, nuclear engineering, geology or in toxicology.

Can you assert that Ronan Farrow is qualified to define the "most toxic place in America?" By what right? I would submit, that since atmospheric pollution kills people, including people who sit watching television to pretend to be educated about important issues, the air may be more toxic than Hanford, since the air kills people - as the reference I provided from a scientific publication in which dogmatic people never bother to read - and Hanford hasn't killed people. If you are here to argue that Hanford, which the lightly educated if educated at all in science, twit (in this area certainly) Ronan Farrow calls "the most toxic place in America," has killed people, you are invited to show as much, either from the Lancet publication or from any other scientific publication.

You are engaging in a rather common logical fallacy, which is characteristic of bad thinking, which hopefully Ronan Farrow studied while studying law, which is the Appeal to Authority Fallacy..

As a subheading to the link I used describing this exercise in poor thinking - there are many web pages around logical fallacies if one is interested in developing critical thinking skills - contains this text:

Generally, a fallacious appeal to authority is one that fails to meet the requirements of a legitimate one: the authority is not a real expert in the relevant area of knowledge, their statement is not concerned with the actual issue, or their views go against the general agreement among experts in that field of study.

Let’s look at various ways this fallacy may occur.

APPEAL TO FALSE AUTHORITY
This is likely the most common way of erroneously citing (supposed) experts. It occurs when someone uses the words of poor or irrelevant authorities as evidence for a claim. In such a case, the authorities are unqualified or their expertise is not relevant to the argument being made.

A typical example of this fallacy would be almost any celebrity endorsement in advertising.


This case amounts to a celebrity endorsement, basically of nuclear paranoia, said paranoia being responsible for killing people since approximately according to the Lancet paper written with input from scientists, epidemiologists, physicians and other medical professions around the world, the most probable number of people who die each year from air pollution - because we don't use nuclear energy - is 6.8 million people.

You were invited to peruse the comprehensive paper to tell me about the deaths associated with what Ronan Farrow calls "the most toxic place in America." You didn't. You chose to tell me about Ronan Farrow's legal degrees. I couldn't care less. As far as I'm concerned, if he's talking about a subject he is not qualified to discuss, he's being a twit.

I have studied nuclear chemistry on a serious level, privately, not professionally, for 30 years. I consider much of the money being spent to "clean up" radioactively contaminated sites to a risk level that now fossil fuel facility could ever match, an immoral waste of money.

How many lives can we save by spending 20 billion dollars to "clean up" Hanford to a standard that some law school graduate arbitrarily declares - after which he is sure to say it's not enough without providing any evidence - and how many lives could we save by using the same 20 billion dollars by providing sanitation services to the 2 billion people on this planet who lack any improved sanitation?

Just because Ronan Farrow has his head up his ass on this subject, doesn't mean I'm required to shove my head up my ass.

OK?

Your statement...

The fact is all of the great energy science has brought us to here, there no way to clean it up and it is killing us. Petroleum or nuclear it’s the same result. It will all kill us and there is nothing we can do about it...


...is as nonsensical as the original statement about the lifetime of plutonium.

You do realize, don't you, that there are literally tens or hundreds of thousands of Ph.D. level scientists - some better than others to be sure - who have studied nuclear science? I am very proud that my son has announced his intention to become one.

I know perfectly well what should be done to stabilize Hanford to a reasonable standard, even if the expensive effort is being made to make "clean it up" to an unreasonable (resource wasting) standard.

It is however technical. If however, one gets one's science from a celebrity with a law degree and a Ph.D. in "God knows what" it would be useless to discuss the facts with someone is who is clearly not qualified to understand them.

I did discuss some of these issues in the link I provided to one of my own posts, but this may not have been as engaging as Ronan Farrow, nuclear twit.

Farrow may be qualified to discuss Harvey Weinstein, a legal matter, and is certainly qualified to discuss issues in his own family, but he is not an expert on any topic connected with science, and is, in fact, in this case, just another journalist who shows zero evidence of having passed a college level science course with a grade of C or better. If he did pass such a course with such a grade or higher, it cannot be said that he got much out of it. Otherwise he wouldn't be making these kind of stupid comments designed to inflate fear and ignorance.

Have a nice evening.

WA-03 Democrat

(3,017 posts)
5. Kindly point me
Sun Sep 19, 2021, 08:35 PM
Sep 2021

"I know perfectly well what should be done to stabilize Hanford to a reasonable standard...I did discuss some of these issues in the link I provided to one of my own posts"

I would greatly appreciate it.

Thank you and have a good night.

NNadir

(33,368 posts)
6. Um, you'd have to be pretty high to think I can compress 30 years of study into a blog post for...
Sun Sep 19, 2021, 08:56 PM
Sep 2021

...someone who gets his science from Ronan Farrow.

I'm not really here for "appreciation" but try this between tokes to get a general flavor:

A Scientific Rationale For Pursuing New Immobilization Forms For So Called "Nuclear Waste."

My journal here is filled with reference to the primary scientific literature, and a fair proportion of it covers fission products and related issues.

NNadir's Journal

Take a few minutes, and run it by John Oliver and Ronan Farrow but there's no need to get back to me to let me know what they think.

I'm a scientist, not an entertainer.

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