Wikipedia:Reference desk/Archives/Science/2023 August 9

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August 9

Risk of explosion when cleaning formaldehyde stains with calcium/hydrogen peroxide

Hi, I’m an M1 in medical school soon due to begin dissecting cadavers preserved in formaldehyde. Everyone is saying that formaldehyde tends to get on everything including scrubs, which I plan to wash with generic oxyclean. What is the risk of using oxyclean on formalin stains?

I know that acetone peroxide is explosive but mixing formaldehyde and hydrogen (calcium) peroxide should ultimately yield performic acid. What makes performic acid more stable than acetone peroxide? Yanping Nora Soong (talk) 03:54, 9 August 2023 (UTC)

I expect there are faculty or staff at the medical school who would be the best people to answer this question. Newyorkbrad (talk) 04:03, 9 August 2023 (UTC)

I wish, I know from practice formaldehyde + peroxide bleach / cleaning agents doesn’t result in explosions so I wanted to ask why mixing acetone with oxidizing agents is potentially so much more explosively hazardous then when formaldehyde is involved. I know acetone is eschewed in industrial use due to the explosion risk. I have a side interest in greener industrial chemistry. Yanping Nora Soong (talk) 12:35, 9 August 2023 (UTC)

Acetone peroxide isn't explosive when dissolved in water. If you look at the ball-and-stick model in the article, you will note that the bonds appear to be under strain (curved, in other words). It is tricky to get and maintain a molecule into that sort of shape. Performic acid is non-toxic. Abductive (reasoning) 04:25, 9 August 2023 (UTC)

Pure Formaldehyde is a pungent, colourless gas that is stored as the aqueous solution (formalin), which is used to preserve animal specimens, though its use for embalming is banned in the EU due to its carcinogenic properties. The OxiClean™ formulation is a combination of ingredients, the key ingredient being sodium percarbonate, sodium carbonate, surfactants and polymer, see www.oxiclean.com. Here are other ways to get formaldehyde smell out of clothes using baking soda , vinegar or air drying. Philvoids (talk) 09:13, 9 August 2023 (UTC)

AFAIK percarbonate is an adduct species - carbonate ions lending general base catalysis to peroxide. Thus it should easily oxidize formaldehyde to performic acid AFAIK. Yanping Nora Soong (talk) 12:39, 9 August 2023 (UTC)

I don’t understand why the high potential energy of acetone peroxide would be due to ring strain. Formaldehyde forms dehydrated polymers as well, and certainly beta-lactam antibiotics don’t tend to explode. This is my fundamental question: what makes acetone peroxide so much more dangerous to handle than performic acid? Is it the resonance stability of performate? Yanping Nora Soong (talk) 12:49, 9 August 2023 (UTC)

I'll grant you, it's been a long time since I was in a cadaver lab, but I don't know that it's necessarily that the formaldehyde gets on your clothes in any great concentrations with that great a regularity, so much that it's such a noxious substance with regard to both airways and skin, that you tend be quite aware of it's presence if even a small amount (or its distinctive scent) does get on your clothes. Formaldehyde has been recognized as a carcinogen and sensitizing agent for a long while now, so you'll certainly have access to barrier sleeves and other PPE. To the left of your inquiry, I know, but hopefully somewhat reassuring. Out of curiosity: did you not work with cadavers in your undergraduate anatomy courses? SnowRise ^{let's rap} 09:05, 9 August 2023 (UTC)

Animals only, and I hadn’t discovered my love for gentler peroxide bleach / cleaning agents then (this was before I worked EMS during the pandemic). Yanping Nora Soong (talk) 12:35, 9 August 2023 (UTC)

It must be a sign of the times and the worsening shortage of available bodies: not so many decades back most universities of any significant size, even those that did not have medical schools and were not research institutions, would still have a body or five for their anatomy programs. Well, may your first 'silent teacher' be something like mine: I just typed out a lengthy list of his many features that made his donation especially valuable to those of us who learned from his body, but I realized it ended up sounding like the most morbid (and possibly even insensitive) version of WP:NOTAFORUM, to those without a common frame of reference. Anyhow, best of luck with M1! SnowRise ^{let's rap} 13:43, 9 August 2023 (UTC)

How can competitive versus noncompetitive inhibition be distinguished on the Hanes–Woolf plot and the Eadie–Hofstee diagram

I can't find any accessible resources online due to the tyrannical hegemony of Lineweaver-Burk. Also, what are the Hanes-Woolf and Eadie-Hofstee equivalents for distinguishing ternary enzyme-substrate1-substrate2 complex formation versus double displacement mechanisms? Yanping Nora Soong (talk) 14:29, 9 August 2023 (UTC)

Yanping Nora Soong, I meant to respond to this much sooner. I'm wondering if maybe I am missing something obvious here, but why is it that you assume that competitive vs. noncompetitive inhibition would be obviously and easily inferable from the dynamics of such a plot? The slope describes the profile of catalyzation, but would it per se do so in a manner that would lead to reliable characterize the reaction in the manner you suggest. I realize I'm answer your question with questions, but again, I'm wondering if I am missing something obvious in your inquiry. SnowRise ^{let's rap} 08:01, 16 August 2023 (UTC)

Is lead removed during metal recycling?

Is lead removed during the recycling of common metals (e.g. steel, aluminum, copper)? If so, how is it achieved? — Preceding unsigned comment added by 134.242.133.1 (talk) 22:17, 9 August 2023 (UTC)

Naturally we have an article on Lead. It doesn't directly answer your question, but it does say " In 2014, the annual global production of lead was about ten million tonnes, over half of which was from recycling." There's more on lead recycling later in that article. HiLo48 (talk) 02:29, 10 August 2023 (UTC)

OP, can you clarify your inquiry a little? Three of the four substances you mention are pure metals composed of one element, and the one that is an alloy doesn't often itself get alloyed with lead--not in significant relative amounts anyway. If you're asking about alloys with refined metal of those other particular elements with lead, this article by *sniff* one of those other encyclopedias might be of interest to you. The one part of the processing of lead it doesn't directly summarize is the recycling of composite materials and products containing the substance, so it does not contain specific figures for you, but it does summarize the most common alloys and their uses, which is a good place to start. There's also our Category:Lead alloys and this source for the same purpose. Purely metal alloys seem to be (unsurprisingly), only a small portion of the overall amount of recycled lead, and this is despite the fact that lead is the most heavily recycled metal, globally. The significant majority of this comes from lead–acid battery recycling: [1]. SnowRise ^{let's rap} 04:13, 10 August 2023 (UTC)

OP here. The question is about removing lead as a contaminant from the output from recycling metallic materials; it is not about recovering lead as a main product of the recycling process. --134.242.133.1 (talk) 04:58, 10 August 2023 (UTC)

Ahhh, I see. Well in that case, a combination of smelting, Electrolysis, and in some cases more exotic forms of chemical purification / extractive metallurgy would be utilized, to answer the second part of your initial question. But considering the same details already covered above, it is important to note that lead is not often alloyed with any of the metals you initially mentioned--at least not relative the massive overall volumes of these metals which get produced and those portions which eventually get recycled. Lead's ductility and other features that have advantages for certain types of machining and manufacturing means it has sometimes been alloyed with other common industrial metals to fashion fixings, bolts and other small parts, but needless to say, the metal has it's drawbacks that constrain its applications, so I wouldn't expect that most purification of any of the metals you mentioned involves more than trivial amounts of removal of lead, at least not when looking at the volume recycled as a whole. SnowRise ^{let's rap} 05:20, 10 August 2023 (UTC)